feat(sync): add Microsoft account connect CLI

nocal account connect microsoft runs the PKCE browser flow, reads /me,
upserts the deterministic account row, and persists tokens to Secret
Service as the final connected-state gate. Account IDs are hashed from
the remote subject so reconnect is idempotent, and a secret-store
failure leaves the same coherent state as a disconnect. Ships a
placeholder client ID with NOCAL_MICROSOFT_CLIENT_ID override until a
real Entra registration exists.

.opencode/agent/coder.md

@@ -0,0 +1,45 @@
+---
+description: Implements bounded, well-specified coding slices for nocal. Owns an explicit file set, writes C++20 with deterministic tests, compiles with strict warnings, runs the relevant test binaries, and reports exact checks. Use for delegated implementation only — not for architecture decisions, cross-cutting changes, or review.
+mode: subagent
+model: openrouter/deepseek/deepseek-v4-flash
+permission:
+  edit: allow
+  bash: allow
+---
+
+You are a coding agent for the nocal repository. You implement bounded slices
+assigned by the lead agent. You do not redefine architecture, expand scope, or
+review your own work for completion.
+
+## Rules
+
+- Stay strictly inside the file and directory set the lead assigns. Preserve
+  unrelated user changes. Touch nothing outside your scope.
+- C++20, existing code style, minimal precise edits. No new runtime
+  dependencies without explicit lead approval.
+- Add or update deterministic tests for the behavior you implement (injected
+  fakes; no network, wall-clock, or randomness).
+- No git mutations (commit, push, reset, rebase, checkout). Read-only git
+  inspection is fine.
+
+## Verification before reporting back
+
+Run from the repository root and report the exact commands and outcomes:
+
+1. `nix-shell --run 'meson compile -C build'` — must compile cleanly.
+2. The specific test binaries for your slice, e.g.
+   `nix-shell --run 'meson test -C build --print-errorlogs <name>'`.
+3. If the lead asked for warning-as-error or sanitizer checks, run exactly
+   what was requested and paste the tail of any failure.
+
+## Report back
+
+Your final message must state:
+
+- Files changed and a one-line summary per file.
+- The exact commands you ran and whether each passed.
+- Limitations, unhandled edge cases, and any mismatch with the shared
+  contracts you were given.
+
+Never claim completion based on visual inspection or intent. If a check failed
+and you could not fix it, say so explicitly.

AGENTS.md

@@ -37,6 +37,13 @@ pass is not sufficient evidence. Small, tightly coupled fixes may be completed
 directly by the lead when delegation would create more coordination cost than
 implementation value.
 
+## Concrete delegation setup (nocal)
+
+A coding subagent is configured at `.opencode/agent/coder.md` with model
+`openrouter/deepseek/deepseek-v4-flash`. It owns bounded implementation slices assigned
+by the lead; the lead retains shared contracts, integration, review, and final
+verification. After any config change, restart opencode to reload agents.
+
 ## Delegation protocol
 
 Before dispatching implementation work, the lead must:

README.md

@@ -182,6 +182,10 @@ them; omission is not mislabeled as a remote deletion tombstone. This avoids
 beta and undocumented delta routes, at the cost of refetching each secondary
 window instead of incrementally updating it.
 
-There is still no account UI/CLI orchestration or live Microsoft credential
-integration, and remote writes remain out of scope. Account setup and
-orchestration are next.
+Account setup begins with `nocal account connect microsoft`: it runs the
+PKCE browser flow, reads `/me`, upserts the deterministic account row, and
+stores the tokens in the Secret Service keyring as the final connected-state
+gate. This build ships a placeholder client ID; live connect requires a real
+mobile/desktop Entra registration supplied via `NOCAL_MICROSOFT_CLIENT_ID`.
+There is still no account TUI or sync orchestration, and remote writes remain
+out of scope.

docs/ARCHITECTURE.md

@@ -288,6 +288,16 @@ This design avoids beta and undocumented per-calendar delta routes. Its
 tradeoff is bandwidth: every secondary window is fetched completely on each
 refresh, while the primary calendar remains incremental.
 
-There is no account UI or CLI orchestration and no live Microsoft credential
-integration yet; tests use injected transports and credentials. Remote writes
-remain out of scope. Account setup and orchestration are next.
+Account setup now has a CLI entry point, `nocal account connect microsoft`.
+It composes the desktop OAuth adapters, libcurl transport, token parsing, one
+`/me` identity read, the sync cache, and the Secret Service store in a fixed
+order: the account row is upserted first, and the versioned secret payload is
+stored last as the connected-state gate. A secret-store failure therefore
+leaves the same coherent state as a disconnect, and reconnecting is idempotent
+because the local account id is a deterministic hash of the remote subject.
+This build carries a placeholder client ID; a real Entra registration is
+supplied through the `NOCAL_MICROSOFT_CLIENT_ID` environment variable (a
+public client ID, never a secret). There is no account TUI and no sync
+orchestration yet; tests use injected transports and credentials. Remote
+writes remain out of scope. Generic `SyncProvider` integration and observable
+sync status are next.

docs/ROADMAP.md

@@ -93,10 +93,35 @@ Completed secondary-calendar stable-v1 reconciliation:
 - Overlapping windows retain events until their last membership is removed
 - No beta or undocumented per-calendar delta dependency
 
+Completed provider-boundary contracts and token broker:
+
+- Generic `SyncProvider`/`SyncObserver` contracts for account connect, sync,
+  and disconnect with staged progress events
+- `OAuthTokenBroker` returning valid per-operation access tokens with a
+  five-minute refresh skew
+- Refresh rotation persisted before use so a new refresh token is never lost;
+  transient refresh failures leave stored credentials untouched
+- 400/401 refresh rejections erase the stored secret and surface
+  `AccountDisconnected` for re-authentication
+- Credential material never appears in exception messages
+
+Completed account setup (CLI):
+
+- `nocal account connect microsoft` runs the PKCE browser flow, reads `/me`,
+  upserts the deterministic account row, and persists tokens to Secret
+  Service as the final connected-state gate
+- Deterministic local account IDs hashed from the remote subject make
+  reconnect idempotent; a secret-store failure leaves the same coherent state
+  as a disconnect
+- Placeholder client ID with `NOCAL_MICROSOFT_CLIENT_ID` override until a
+  real Entra mobile/desktop registration exists
+- Deterministic failure-path tests: rejection, token errors, identity
+  failure, storage failure, and credential redaction in error messages
+
 Next provider-boundary slices:
 
-- Account setup and CLI/TUI orchestration with live credential integration
-- Generic `SyncProvider` integration and observable sync status
+- TUI account orchestration and generic `SyncProvider` integration with
+  observable sync status
 
 ## 0.3 — CalDAV
 
@@ -113,9 +138,10 @@ Next provider-boundary slices:
 
 The Graph read boundary uses stable v1 delta for the primary calendar and
 complete stable-v1 calendar views for secondary calendars; it deliberately
-avoids beta and undocumented per-calendar delta routes. No account UI/CLI
-orchestration or live Microsoft credential integration exists yet, and remote
-writes remain out of scope.
+avoids beta and undocumented per-calendar delta routes. Account connect exists
+as a CLI command with live credential integration through Secret Service, but
+there is no account TUI or sync orchestration yet, and remote writes remain
+out of scope.
 
 ## 1.0 — distribution quality
 

include/nocal/sync/microsoft_account.hpp

@@ -0,0 +1,70 @@
+#pragma once
+
+#include "nocal/storage/sync_cache.hpp"
+#include "nocal/sync/oauth.hpp"
+
+#include <cstdint>
+#include <functional>
+#include <stdexcept>
+#include <string>
+#include <string_view>
+
+namespace nocal::sync {
+
+class HttpTransport;
+class OAuthSecretStore;
+
+// Placeholder used when no real Entra application registration is available.
+// It is not a registered client; interactive connect with it fails at the
+// authorization endpoint. Override with the NOCAL_MICROSOFT_CLIENT_ID
+// environment variable. A client ID is public configuration, never a secret.
+inline constexpr std::string_view microsoft_client_id_placeholder =
+    "nocal-unregistered-client-id";
+
+// Client ID used for interactive connect: the NOCAL_MICROSOFT_CLIENT_ID
+// environment variable when set and non-empty, otherwise the placeholder.
+[[nodiscard]] std::string default_microsoft_client_id();
+
+// Public-desktop Microsoft OAuth configuration for the multitenant
+// organizational and personal Microsoft account audience with delegated
+// read-only scopes. The open-source binary never embeds a client secret.
+[[nodiscard]] OAuthClientConfig microsoft_oauth_config(std::string client_id);
+
+class MicrosoftAccountError final : public std::runtime_error {
+public:
+    using std::runtime_error::runtime_error;
+};
+
+// Deterministic local account id derived from the stable remote subject, so
+// reconnecting the same Microsoft account upserts the same cache row and
+// reuses the same Secret Service key.
+[[nodiscard]] std::string microsoft_account_id(std::string_view remote_subject);
+
+// Runs one interactive Microsoft account connection:
+//   1. authorization-code flow with PKCE S256 (one browser launch, one
+//      loopback callback, one token request) via authorize_with_pkce;
+//   2. strict token parsing that requires an initial refresh token;
+//   3. one /me identity read for the remote subject and display name;
+//   4. the account row upserted into the sync cache;
+//   5. the versioned token payload persisted to the Secret Service store.
+//
+// Invariants and failure semantics:
+//  - The account is connected only after step 5 succeeds; there is no
+//    plaintext fallback and no partial connected state.
+//  - Failure before step 4 leaves the cache and the secret store untouched.
+//  - Failure in step 5 leaves a cached account without credentials — the same
+//    coherent state that disconnecting produces. Reconnecting is idempotent
+//    because the account id is deterministic.
+//  - The access token is never retained after return, and error messages
+//    never contain credential material.
+[[nodiscard]] storage::CachedAccount connect_microsoft_account(
+    const OAuthClientConfig& config,
+    BrowserLauncher& browser,
+    AuthorizationCallbackReceiver& receiver,
+    HttpTransport& transport,
+    EntropySource& entropy,
+    OAuthSecretStore& secret_store,
+    storage::SyncCache& cache,
+    const std::function<std::int64_t()>& clock);
+
+} // namespace nocal::sync

include/nocal/sync/microsoft_graph.hpp

@@ -6,6 +6,7 @@
 #include <cstdint>
 #include <stdexcept>
 #include <string>
+#include <string_view>
 
 namespace nocal::sync {
 
@@ -28,6 +29,13 @@ public:
     using std::runtime_error::runtime_error;
 };
 
+// Validated /me identity. Fetched without persisting anything so account
+// connect can derive the deterministic local account id before any cache write.
+struct MicrosoftGraphIdentity {
+    std::string remote_subject;
+    std::string display_name;
+};
+
 // Read-only Microsoft Graph v1.0 synchronization. Calendar discovery covers
 // every calendar returned by /me/calendars. Stable v1.0 event delta is used for
 // the primary calendar and complete calendarView reconciliation for secondary
@@ -36,6 +44,10 @@ class MicrosoftGraphSync {
 public:
     MicrosoftGraphSync(HttpTransport& transport, storage::SyncCache& cache);
 
+    // Requires delegated User.Read. Reads /me and returns the validated
+    // identity without touching the cache; the access token is not retained.
+    [[nodiscard]] MicrosoftGraphIdentity fetch_identity(std::string_view access_token) const;
+
     // Requires delegated User.Read. A complete and validated /me response is
     // persisted atomically; failures leave the cached account unchanged.
     storage::CachedAccount refresh_account(const MicrosoftGraphCredentials& credentials);

include/nocal/sync/provider.hpp

@@ -0,0 +1,56 @@
+#pragma once
+
+#include <functional>
+#include <optional>
+#include <string>
+#include <string_view>
+
+namespace nocal::sync {
+
+enum class SyncStage {
+    authenticating,
+    refreshing_identity,
+    discovering_calendars,
+    syncing_calendar,
+    completed,
+};
+
+struct SyncProgressEvent {
+    SyncStage stage{SyncStage::authenticating};
+    std::string account_id;
+    std::string calendar_name;
+    std::size_t calendars_completed{0};
+    std::size_t calendars_total{0};
+};
+
+class SyncObserver {
+public:
+    virtual ~SyncObserver() = default;
+    virtual void on_sync_progress(const SyncProgressEvent& event) = 0;
+};
+
+struct ConnectedAccount {
+    std::string account_id;
+    std::string display_name;
+};
+
+class SyncProvider {
+public:
+    virtual ~SyncProvider() = default;
+
+    [[nodiscard]] virtual std::string_view provider_id() const noexcept = 0;
+
+    // Interactive connect: runs provider auth, stores credentials, registers
+    // account. Must not leave partial connected state on failure.
+    virtual ConnectedAccount connect_account() = 0;
+
+    // Syncs one account's calendars and windows; reports progress via observer.
+    // May continue past individual calendar failures but reports them.
+    virtual void sync_account(std::string_view account_id, SyncObserver& observer) = 0;
+
+    // Removes credentials for the account. Cached provider data is left in place
+    // (deterministic IDs make re-add idempotent). Unknown account is an error.
+    virtual void disconnect_account(std::string_view account_id) = 0;
+};
+
+} // namespace nocal::sync

include/nocal/sync/token_broker.hpp

@@ -0,0 +1,58 @@
+#pragma once
+
+#include "nocal/sync/oauth.hpp"
+#include "nocal/sync/oauth_tokens.hpp"
+
+#include <functional>
+#include <optional>
+#include <stdexcept>
+#include <string>
+#include <string_view>
+
+namespace nocal::sync {
+
+class OAuthSecretStore;
+class HttpTransport;
+
+class AccountDisconnected final : public std::runtime_error {
+public:
+    explicit AccountDisconnected(std::string message)
+        : std::runtime_error(std::move(message)) {}
+};
+
+class OAuthTokenBroker {
+public:
+    // Constructs a broker for one OAuth provider configuration.
+    // `clock` returns the current epoch seconds for expiry calculations.
+    // It must be monotonic-ish (system_clock is fine).
+    OAuthTokenBroker(const OAuthClientConfig& config,
+                     HttpTransport& transport,
+                     OAuthSecretStore& secret_store,
+                     std::function<std::int64_t()> clock);
+
+    // Returns a valid access token for the account, refreshing and persisting
+    // the rotated tokens when the stored access token is expired or within
+    // 5 minutes of expiry.
+    //
+    // Failure semantics:
+    // - Transport error, 429, 5xx, timeout -> throws std::runtime_error;
+    //   secret store is NOT touched.
+    // - 400/401 on refresh (invalid_grant, unauthorized_client, etc.) ->
+    //   erases the secret from the store, throws AccountDisconnected
+    //   (re-auth required).
+    // - Parsing/validation failure on refresh response -> throws
+    //   std::runtime_error; secret is NOT erased (may be transient malformed
+    //   response).
+    // - Secret store load failure (missing, locked, cancelled) -> throws
+    //   std::runtime_error; no erase.
+    [[nodiscard]] OAuthTokens valid_tokens(std::string_view account_id);
+
+private:
+    const OAuthClientConfig config_;
+    HttpTransport& transport_;
+    OAuthSecretStore& secret_store_;
+    std::function<std::int64_t()> clock_;
+    static constexpr std::int64_t refresh_skew_seconds = 300; // 5 min
+};
+
+} // namespace nocal::sync

meson.build

@@ -28,10 +28,12 @@ nocal_sources = files(
   'src/storage/sync_cache.cpp',
   'src/sync/curl_http.cpp',
   'src/sync/desktop_oauth.cpp',
+  'src/sync/microsoft_account.cpp',
   'src/sync/microsoft_graph.cpp',
   'src/sync/oauth.cpp',
   'src/sync/oauth_tokens.cpp',
   'src/sync/secret_store.cpp',
+  'src/sync/token_broker.cpp',
   'src/tui/Screen.cpp',
   'src/tui/EventEditor.cpp',
   'src/tui/Terminal.cpp',
@@ -45,6 +47,11 @@ nocal_dep = declare_dependency(include_directories: inc, link_with: nocal_lib,
 nocal_executable = executable('nocal', 'src/main.cpp',
   dependencies: nocal_dep, install: true)
 
+util = meson.get_compiler('cpp').find_library('util', required: false)
+pty_smoke = executable('tui-pty-smoke', 'tests/tui_pty_smoke.cpp',
+  dependencies: util)
+test('tui-pty-smoke', pty_smoke, args: [nocal_executable], timeout: 60)
+
 domain_tests = executable('domain-tests', 'tests/domain_tests.cpp',
   dependencies: nocal_dep)
 test('domain', domain_tests)
@@ -72,6 +79,12 @@ test('desktop-oauth', desktop_oauth_tests)
 oauth_token_tests = executable('oauth-token-tests',
   'tests/oauth_token_tests.cpp', dependencies: nocal_dep)
 test('oauth-tokens', oauth_token_tests)
+token_broker_tests = executable('token-broker-tests',
+  'tests/token_broker_tests.cpp', dependencies: nocal_dep)
+test('token-broker', token_broker_tests)
+microsoft_account_tests = executable('microsoft-account-tests',
+  'tests/microsoft_account_tests.cpp', dependencies: nocal_dep)
+test('microsoft-account', microsoft_account_tests)
 secret_store_tests = executable('secret-store-tests',
   'tests/secret_store_tests.cpp', dependencies: nocal_dep)
 test('secret-store', shell,

src/main.cpp

@@ -1,6 +1,11 @@
 #include "nocal/domain/calendar_transfer.hpp"
 #include "nocal/domain/date.hpp"
 #include "nocal/storage/ics_store.hpp"
+#include "nocal/storage/sync_cache.hpp"
+#include "nocal/sync/curl_http.hpp"
+#include "nocal/sync/desktop_oauth.hpp"
+#include "nocal/sync/microsoft_account.hpp"
+#include "nocal/sync/secret_store.hpp"
 #include "nocal/tui/Screen.hpp"
 #include "nocal/tui/TuiApp.hpp"
 
@@ -13,6 +18,7 @@
 #include <stdexcept>
 #include <string>
 #include <string_view>
+#include <system_error>
 #include <utility>
 #include <vector>
 
@@ -45,6 +51,61 @@ std::filesystem::path default_calendar_path()
     return "calendar.ics";
 }
 
+std::filesystem::path default_sync_cache_path()
+{
+    if (const char* data_home = std::getenv("XDG_DATA_HOME");
+        data_home != nullptr && *data_home != '\0') {
+        return std::filesystem::path{data_home} / "nocal" / "sync.db";
+    }
+    if (const char* home = std::getenv("HOME"); home != nullptr && *home != '\0') {
+        return std::filesystem::path{home} / ".local" / "share" / "nocal" / "sync.db";
+    }
+    return "sync.db";
+}
+
+int connect_microsoft_account()
+{
+    const std::string client_id = nocal::sync::default_microsoft_client_id();
+    if (client_id == nocal::sync::microsoft_client_id_placeholder) {
+        std::cerr <<
+            "nocal: this build has no registered Microsoft application client ID.\n"
+            "Register a mobile and desktop public client with redirect URI\n"
+            "http://localhost/nocal/oauth/callback, then set NOCAL_MICROSOFT_CLIENT_ID.\n";
+        return EXIT_FAILURE;
+    }
+    const std::filesystem::path cache_path = default_sync_cache_path();
+    std::error_code error;
+    std::filesystem::create_directories(cache_path.parent_path(), error);
+    if (error) {
+        throw std::runtime_error("cannot create " + cache_path.parent_path().string() +
+                                 ": " + error.message());
+    }
+    nocal::storage::SyncCache cache(cache_path);
+    nocal::sync::CurlHttpTransport transport;
+    nocal::sync::XdgBrowserLauncher browser;
+    nocal::sync::LoopbackCallbackReceiver receiver;
+    nocal::sync::SystemEntropySource entropy;
+    nocal::sync::LibsecretOAuthSecretStore secrets;
+    const auto account = nocal::sync::connect_microsoft_account(
+        nocal::sync::microsoft_oauth_config(client_id), browser, receiver, transport,
+        entropy, secrets, cache, [] {
+            return std::chrono::duration_cast<std::chrono::seconds>(
+                       std::chrono::system_clock::now().time_since_epoch())
+                .count();
+        });
+    std::cout << "Connected " << account.display_name << " (" << account.id << ")\n";
+    return std::cout ? EXIT_SUCCESS : EXIT_FAILURE;
+}
+
+int account_command(int argc, char** argv)
+{
+    if (argc == 3 && std::string_view{argv[1]} == "connect" &&
+        std::string_view{argv[2]} == "microsoft") {
+        return connect_microsoft_account();
+    }
+    throw std::invalid_argument("usage: nocal account connect microsoft");
+}
+
 void print_help(std::ostream& output)
 {
     output <<
@@ -60,6 +121,9 @@ void print_help(std::ostream& output)
         "      --no-color       disable ANSI styling\n"
         "  -h, --help           show this help\n"
         "  -V, --version        show the version\n\n"
+        "Accounts: nocal account connect microsoft\n"
+        "          links a Microsoft account (browser sign-in, tokens stay in\n"
+        "          the Secret Service keyring) and exits.\n\n"
         "Keys: arrows/hjkl move days, PageUp/PageDown or p/n change month,\n"
         "      Tab/Shift-Tab focus appointments, Enter reads, Esc returns,\n"
         "      a adds, e edits, d deletes; Ctrl-S saves inside the editor,\n"
@@ -313,6 +377,9 @@ int export_calendar(const std::filesystem::path& source_path,
 int main(int argc, char** argv)
 {
     try {
+        if (argc >= 2 && std::string_view{argv[1]} == "account") {
+            return account_command(argc - 1, argv + 1);
+        }
         const auto options = parse_options(argc, argv);
         auto loaded = nocal::storage::IcsStore::load(options.calendar_path);
         print_warnings(loaded, options.calendar_path);

src/sync/microsoft_account.cpp

@@ -0,0 +1,117 @@
+#include "nocal/sync/microsoft_account.hpp"
+
+#include "nocal/sync/microsoft_graph.hpp"
+#include "nocal/sync/oauth.hpp"
+#include "nocal/sync/oauth_tokens.hpp"
+#include "nocal/sync/secret_store.hpp"
+
+#include <openssl/evp.h>
+
+#include <array>
+#include <cstdint>
+#include <cstdlib>
+#include <functional>
+#include <stdexcept>
+#include <string>
+#include <string_view>
+
+namespace nocal::sync {
+namespace {
+
+[[nodiscard]] std::string sha256_hex(std::string_view input) {
+    std::array<unsigned char, 32> digest{};
+    unsigned int size = 0;
+    if (EVP_Digest(input.data(), input.size(), digest.data(), &size, EVP_sha256(), nullptr) != 1
+        || size != digest.size()) {
+        throw std::runtime_error("cryptographic failure");
+    }
+    static constexpr char hexadecimal[] = "0123456789abcdef";
+    std::string output;
+    output.reserve(digest.size() * 2U);
+    for (const unsigned char byte : digest) {
+        output.push_back(hexadecimal[byte >> 4U]);
+        output.push_back(hexadecimal[byte & 0x0fU]);
+    }
+    return output;
+}
+
+} // namespace
+
+std::string default_microsoft_client_id() {
+    const char* value = std::getenv("NOCAL_MICROSOFT_CLIENT_ID");
+    if (value != nullptr && value[0] != '\0') {
+        return std::string(value);
+    }
+    return std::string(microsoft_client_id_placeholder);
+}
+
+OAuthClientConfig microsoft_oauth_config(std::string client_id) {
+    OAuthClientConfig config;
+    config.client_id = std::move(client_id);
+    config.authorization_endpoint =
+        "https://login.microsoftonline.com/common/oauth2/v2.0/authorize";
+    config.token_endpoint = "https://login.microsoftonline.com/common/oauth2/v2.0/token";
+    config.scopes = {"offline_access", "User.Read", "Calendars.Read"};
+    return config;
+}
+
+std::string microsoft_account_id(std::string_view remote_subject) {
+    std::string input("account");
+    input.push_back('\0');
+    input += "microsoft-graph";
+    input.push_back('\0');
+    input += remote_subject;
+    return std::string("graph-account-") + sha256_hex(input);
+}
+
+storage::CachedAccount connect_microsoft_account(const OAuthClientConfig& config,
+    BrowserLauncher& browser, AuthorizationCallbackReceiver& receiver,
+    HttpTransport& transport, EntropySource& entropy, OAuthSecretStore& secret_store,
+    storage::SyncCache& cache, const std::function<std::int64_t()>& clock) {
+    // Step 1: authorization-code flow with PKCE S256
+    HttpResponse response;
+    try {
+        response = authorize_with_pkce(config, browser, receiver, transport, entropy);
+    } catch (const std::exception&) {
+        throw MicrosoftAccountError("Microsoft authorization failed");
+    }
+
+    // Step 2: strict token parsing (requires initial refresh token)
+    OAuthTokens tokens;
+    try {
+        tokens = parse_oauth_token_response(response.body, clock());
+    } catch (const std::exception&) {
+        throw MicrosoftAccountError("Microsoft token response invalid");
+    }
+
+    // Step 3: one /me identity read
+    MicrosoftGraphSync graph{transport, cache};
+    MicrosoftGraphIdentity identity;
+    try {
+        identity = graph.fetch_identity(tokens.access_token);
+    } catch (const std::exception&) {
+        throw MicrosoftAccountError("Microsoft identity read failed");
+    }
+
+    // Step 4: upsert account into the sync cache
+    const std::string account_id = microsoft_account_id(identity.remote_subject);
+    const storage::CachedAccount account{
+        account_id, "microsoft-graph", identity.remote_subject, identity.display_name};
+    try {
+        cache.upsert_account(account);
+    } catch (const std::exception&) {
+        throw MicrosoftAccountError("sync cache update failed");
+    }
+
+    // Step 5: persist credentials to the secret store
+    // On failure the cached account row remains (documented disconnected state).
+    try {
+        secret_store.store(account_id, tokens);
+    } catch (const std::exception&) {
+        throw MicrosoftAccountError("credential storage failed");
+    }
+
+    return account;
+}
+
+} // namespace nocal::sync

src/sync/microsoft_graph.cpp

@@ -533,19 +533,32 @@ struct DeltaContinuation {
 MicrosoftGraphSync::MicrosoftGraphSync(HttpTransport& transport, storage::SyncCache& cache)
     : transport_(transport), cache_(cache) {}
 
+MicrosoftGraphIdentity MicrosoftGraphSync::fetch_identity(
+    std::string_view access_token) const {
+    try {
+        const MicrosoftGraphCredentials credentials{"identity", std::string(access_token)};
+        validate_credentials(credentials);
+        const nlohmann::json object = parse_json_object(
+            send_graph(transport_, std::string(graph_v1) + "/me", credentials).body);
+        MicrosoftGraphIdentity identity{required_string(object, "id"),
+            optional_string(object, "displayName")};
+        if (identity.display_name.empty()) {
+            identity.display_name = required_string(object, "userPrincipalName");
+        }
+        return identity;
+    } catch (...) {
+        throw MicrosoftGraphError("Microsoft Graph identity read failed");
+    }
+}
+
 CachedAccount MicrosoftGraphSync::refresh_account(
     const MicrosoftGraphCredentials& credentials) {
     try {
         validate_credentials(credentials);
-        const nlohmann::json object =
-            parse_json_object(send_graph(transport_, std::string(graph_v1) + "/me", credentials).body);
-        const std::string remote_subject = required_string(object, "id");
-        std::string display_name = optional_string(object, "displayName");
-        if (display_name.empty()) {
-            display_name = required_string(object, "userPrincipalName");
-        }
+        const MicrosoftGraphIdentity identity = fetch_identity(credentials.access_token);
         CachedAccount account{
-            credentials.account_id, "microsoft-graph", remote_subject, std::move(display_name)};
+            credentials.account_id, "microsoft-graph", identity.remote_subject,
+            identity.display_name};
         cache_.upsert_account(account);
         return account;
     } catch (...) {

src/sync/token_broker.cpp

@@ -0,0 +1,147 @@
+#include "nocal/sync/token_broker.hpp"
+
+#include "nocal/sync/oauth.hpp"
+#include "nocal/sync/oauth_tokens.hpp"
+#include "nocal/sync/secret_store.hpp"
+
+#include <cstdint>
+#include <stdexcept>
+#include <string>
+#include <string_view>
+#include <vector>
+
+namespace nocal::sync {
+namespace {
+
+[[nodiscard]] std::string percent_encode(std::string_view value) {
+    static constexpr char hex[] = "0123456789ABCDEF";
+    std::string result;
+    result.reserve(value.size());
+    for (const unsigned char character : value) {
+        const bool ascii_alphanumeric = (character >= 'A' && character <= 'Z')
+            || (character >= 'a' && character <= 'z')
+            || (character >= '0' && character <= '9');
+        if (ascii_alphanumeric || character == '-' || character == '.' || character == '_'
+            || character == '~') {
+            result.push_back(static_cast<char>(character));
+        } else {
+            result.push_back('%');
+            result.push_back(hex[character >> 4U]);
+            result.push_back(hex[character & 0x0fU]);
+        }
+    }
+    return result;
+}
+
+[[nodiscard]] std::string join_scopes(const std::vector<std::string>& scopes) {
+    std::string result;
+    for (const std::string& scope : scopes) {
+        if (!result.empty()) {
+            result.push_back(' ');
+        }
+        result += scope;
+    }
+    return result;
+}
+
+void append_parameter(
+    std::string& output, bool& first, std::string_view name, std::string_view value) {
+    if (!first) {
+        output.push_back('&');
+    }
+    first = false;
+    output += name;
+    output.push_back('=');
+    output += percent_encode(value);
+}
+
+[[nodiscard]] std::string make_refresh_body(const OAuthClientConfig& config,
+    std::string_view refresh_token, const std::string& scope) {
+    std::string body;
+    bool first = true;
+    append_parameter(body, first, "grant_type", "refresh_token");
+    append_parameter(body, first, "client_id", config.client_id);
+    append_parameter(body, first, "refresh_token", refresh_token);
+    if (!scope.empty()) {
+        append_parameter(body, first, "scope", scope);
+    }
+    return body;
+}
+
+} // namespace
+
+OAuthTokenBroker::OAuthTokenBroker(const OAuthClientConfig& config,
+    HttpTransport& transport, OAuthSecretStore& secret_store,
+    std::function<std::int64_t()> clock)
+    : config_(config), transport_(transport), secret_store_(secret_store), clock_(clock) {}
+
+OAuthTokens OAuthTokenBroker::valid_tokens(std::string_view account_id) {
+    // 1. Load stored tokens
+    std::optional<OAuthTokens> stored_opt;
+    try {
+        stored_opt = secret_store_.load(std::string(account_id));
+    } catch (const SecretStoreError&) {
+        throw;
+    } catch (const std::exception& e) {
+        throw std::runtime_error(std::string("failed to load tokens: ") + e.what());
+    }
+
+    if (!stored_opt.has_value()) {
+        throw std::runtime_error("account not connected: " + std::string(account_id));
+    }
+
+    const OAuthTokens& stored = *stored_opt;
+    const std::int64_t now = clock_();
+
+    // 2. Check if token is still valid (beyond now + 300s skew)
+    if (stored.expires_at_epoch_seconds > now + refresh_skew_seconds) {
+        return stored;
+    }
+
+    // 3. Refresh token
+    const std::string scope = join_scopes(config_.scopes);
+    const std::string body = make_refresh_body(config_, stored.refresh_token, scope);
+
+    HttpRequest request;
+    request.method = HttpMethod::post;
+    request.url = config_.token_endpoint;
+    request.headers = {{"Content-Type", "application/x-www-form-urlencoded"}};
+    request.body = body;
+
+    HttpResponse response;
+    try {
+        response = transport_.send(request);
+    } catch (const std::exception& e) {
+        throw std::runtime_error(std::string("transport error: ") + e.what());
+    }
+
+    // 4. Handle response
+    if (response.status == 200) {
+        OAuthTokens parsed;
+        try {
+            parsed = parse_oauth_token_response(response.body, now, stored.refresh_token);
+        } catch (const std::exception& e) {
+            throw std::runtime_error(std::string("parse error: ") + e.what());
+        }
+
+        // Persist first, then return
+        try {
+            secret_store_.store(std::string(account_id), parsed);
+        } catch (const std::exception& e) {
+            throw std::runtime_error(std::string("store error: ") + e.what());
+        }
+
+        return parsed;
+    } else if (response.status == 400 || response.status == 401) {
+        try {
+            secret_store_.erase(std::string(account_id));
+        } catch (const std::exception& e) {
+            throw std::runtime_error(std::string("erase error: ") + e.what());
+        }
+        throw AccountDisconnected("account " + std::string(account_id) + " disconnected");
+    } else {
+        throw std::runtime_error("unexpected status code: " + std::to_string(response.status));
+    }
+}
+
+} // namespace nocal::sync

src/tui/EventEditor.cpp

@@ -7,6 +7,7 @@
 #include <cstdint>
 #include <cstdio>
 #include <ctime>
+#include <initializer_list>
 #include <random>
 #include <sstream>
 #include <stdexcept>
@@ -253,6 +254,49 @@ std::string horizontal_line(const int width, const std::string_view left,
     return result;
 }
 
+struct KeyHint {
+    std::string_view key;
+    std::string_view label;
+};
+
+int hints_width(const KeyHint* const hints, const std::size_t count)
+{
+    int width = 0;
+    for (std::size_t index = 0; index < count; ++index) {
+        if (index != 0) width += 3;
+        width += static_cast<int>(hints[index].key.size() + 1 + hints[index].label.size());
+    }
+    return width;
+}
+
+// Key bold, label dim, three spaces between hints; the plain layout is
+// identical with ANSI disabled. Hints drop from the end to fit.
+std::string render_hints(const std::initializer_list<KeyHint> hints, const int width,
+                         const bool ansi)
+{
+    std::size_t count = hints.size();
+    while (count > 0 && hints_width(hints.begin(), count) > width) --count;
+    std::string result;
+    for (std::size_t index = 0; index < count; ++index) {
+        if (index != 0) result += "   ";
+        result += style(std::string{hints.begin()[index].key}, "1", ansi);
+        result += ' ';
+        result += style(std::string{hints.begin()[index].label}, "2", ansi);
+    }
+    const int used = hints_width(hints.begin(), count);
+    if (used < width) result.append(static_cast<std::size_t>(width - used), ' ');
+    return result;
+}
+
+std::string hints_interior_line(const std::initializer_list<KeyHint> hints, const int width,
+                                const bool ansi)
+{
+    if (width <= 0) return {};
+    if (width == 1) return "│";
+    if (width <= 3) return interior_line({}, width);
+    return "│  " + render_hints(hints, width - 4, ansi) + "│";
+}
+
 } // namespace
 
 EventEditor::EventEditor(const Date selected_day)
@@ -440,8 +484,9 @@ std::string EventEditor::render(const int requested_width, const int requested_h
                            : editing_ ? "  NOCAL · EDIT APPOINTMENT"
                                       : "  NOCAL · NEW APPOINTMENT";
     lines.push_back(styled_interior_line(heading, width, "1", ansi));
-    lines.push_back(styled_interior_line("  Tab/↓ next  Shift-Tab/↑ back  Space toggle",
-                                         width, "2", ansi));
+    lines.push_back(hints_interior_line(
+        {{"Tab", "next field"}, {"Shift-Tab", "previous field"}, {"Space", "toggle"}},
+        width, ansi));
     lines.push_back(styled_interior_line(
         original_.time_basis == TimeBasis::zoned && !original_.time_zone.empty()
             ? "  Times shown in source zone: " + original_.time_zone
@@ -470,8 +515,10 @@ std::string EventEditor::render(const int requested_width, const int requested_h
     }
 
     lines.push_back(rule);
-    lines.push_back(interior_line(error_.empty() ? "  Ready" : "  ! " + error_, width));
-    lines.push_back(styled_interior_line("  Ctrl-S save    Esc cancel", width, "1", ansi));
+    lines.push_back(error_.empty()
+                        ? styled_interior_line("  Ready", width, "2", ansi)
+                        : styled_interior_line("  ! " + error_, width, "1;31", ansi));
+    lines.push_back(hints_interior_line({{"Ctrl-S", "save"}, {"Esc", "cancel"}}, width, ansi));
     lines.push_back(bottom);
 
     // Keep the active field visible on short terminals by selecting a window

src/tui/Screen.cpp

@@ -17,6 +17,9 @@ using namespace std::chrono;
 constexpr std::array<std::string_view, 12> month_names{
     "January", "February", "March", "April", "May", "June",
     "July", "August", "September", "October", "November", "December"};
+constexpr std::array<std::string_view, 12> month_short{
+    "Jan", "Feb", "Mar", "Apr", "May", "Jun",
+    "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
 constexpr std::array<std::string_view, 7> weekday_long{
     "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"};
 constexpr std::array<std::string_view, 7> weekday_short{
@@ -143,6 +146,62 @@ std::string styled(const std::string_view text, const std::string_view code, con
     return "\x1b[" + std::string{code} + "m" + std::string{text} + "\x1b[0m";
 }
 
+struct KeyHint {
+    std::string_view key;
+    std::string_view label;
+};
+
+int hints_display_width(const std::span<const KeyHint> hints) {
+    int total = 0;
+    for (std::size_t index = 0; index < hints.size(); ++index) {
+        if (index != 0) total += 3; // three spaces between hints
+        total += display_width(hints[index].key) + 1 + display_width(hints[index].label);
+    }
+    return total;
+}
+
+// Renders hint chips in at most `width` columns, dropping hints from the end
+// (lowest priority) until the rest fit, then pads to exactly `width`.
+std::string render_hints(const std::span<const KeyHint> hints, const int width,
+                         const bool ansi) {
+    const int w = std::max(0, width);
+    std::size_t shown = hints.size();
+    while (shown > 0 && hints_display_width(hints.first(shown)) > w) --shown;
+    std::string result;
+    for (std::size_t index = 0; index < shown; ++index) {
+        if (index != 0) result += "   ";
+        result += styled(hints[index].key, "1", ansi);
+        result += ' ';
+        result += styled(hints[index].label, "2", ansi);
+    }
+    const int used = hints_display_width(hints.first(shown));
+    if (used < w) result.append(static_cast<std::size_t>(w - used), ' ');
+    return result;
+}
+
+// Status left-aligned in its own style, hints right-aligned with at least two
+// spaces between. The result is always exactly `width` columns wide.
+std::string status_bar(const std::string_view status, const std::string_view status_style,
+                       const std::span<const KeyHint> hints, const int width, const bool ansi) {
+    const int w = std::max(0, width);
+    if (w == 0) return {};
+    std::size_t shown = hints.size();
+    while (shown > 0 &&
+           display_width(status) + 2 + hints_display_width(hints.first(shown)) > w) {
+        --shown;
+    }
+    const int hints_width = hints_display_width(hints.first(shown));
+    const int status_budget = shown > 0 ? std::max(0, w - 2 - hints_width) : w;
+    const std::string fitted = fit_text(status, status_budget);
+    std::string result = fitted.empty() ? std::string{} : styled(fitted, status_style, ansi);
+    if (shown > 0) {
+        const int gap = std::max(2, w - display_width(fitted) - hints_width);
+        result.append(static_cast<std::size_t>(gap), ' ');
+        result += render_hints(hints.first(shown), hints_width, ansi);
+    }
+    return result;
+}
+
 std::string two_digits(const unsigned value) {
     std::array<char, 3> result{'0', '0', '\0'};
     result[0] = static_cast<char>('0' + (value / 10) % 10);
@@ -391,15 +450,21 @@ std::string detail_frame(std::span<const CalendarItem> items, const ScreenState&
     if (!focused.description.empty()) {
         add(" NOTES", "2;1");
         for (const auto& line : wrap_text(printable_text(focused.description, true),
-                                         std::max(1, inner - 2))) {
+                                          std::max(1, inner - 2))) {
             add(" " + line);
         }
     } else {
         add(" No notes for this appointment.", "2;3");
     }
 
-    const auto footer = " ↑↓/Tab browse  / search  e edit  d delete  u undo  Ctrl-R redo  Esc back  " +
-                        std::to_string(ordinal) + "/" + std::to_string(total) + " ";
+    const auto footer_hints = std::array{
+        KeyHint{"Tab", "next"},
+        KeyHint{"/", "search"},
+        KeyHint{"e", "edit"},
+        KeyHint{"d", "del"},
+        KeyHint{"Esc", "back"},
+    };
+    const auto ordinal_str = std::to_string(ordinal) + "/" + std::to_string(total);
     const int body_rows = height - 2;
     std::ostringstream output;
     output << border({inner}, "┌", "", "┐") << '\n';
@@ -407,8 +472,24 @@ std::string detail_frame(std::span<const CalendarItem> items, const ScreenState&
         std::string value(static_cast<std::size_t>(inner), ' ');
         std::string style;
         if (line == body_rows - 1) {
-            value = fit_text(footer, inner);
-            style = "7";
+            // Hints left, ordinal right; both drop gracefully on narrow frames.
+            const int ordinal_width = display_width(ordinal_str);
+            std::size_t shown = footer_hints.size();
+            while (shown > 0 &&
+                   hints_display_width(std::span{footer_hints}.first(shown)) + 2 +
+                           ordinal_width >
+                       inner) {
+                --shown;
+            }
+            const int hints_width =
+                hints_display_width(std::span{footer_hints}.first(shown));
+            const bool show_ordinal =
+                ordinal_width + (shown > 0 ? hints_width + 2 : 0) <= inner;
+            value = render_hints(std::span{footer_hints}.first(shown), hints_width,
+                                 state.ansi);
+            const int padding = inner - hints_width - (show_ordinal ? ordinal_width : 0);
+            value.append(static_cast<std::size_t>(std::max(0, padding)), ' ');
+            if (show_ordinal) value += styled(ordinal_str, "2", state.ansi);
         } else if (line < static_cast<int>(content.size())) {
             value = content[static_cast<std::size_t>(line)].first;
             style = content[static_cast<std::size_t>(line)].second;
@@ -429,12 +510,17 @@ std::string delete_confirmation_frame(const ScreenState& state, const CalendarIt
     const int inner = width - 2;
     const auto& detail_title = focused.detail_title.empty() ? focused.title : focused.detail_title;
     const auto title = detail_title.empty() ? std::string{"(untitled)"}
-                                             : printable_text(detail_title);
+                                              : printable_text(detail_title);
     const auto question = fit_text(focused.recurring
-                                       ? " Delete entire recurring series “" + title + "”?"
-                                       : " Delete “" + title + "”?",
-                                   inner);
-    const auto controls = fit_text(" y confirm   n/Esc cancel", inner);
+                                        ? " Delete entire recurring series “" + title + "”?"
+                                        : " Delete “" + title + "”?",
+                                    inner);
+    const std::array confirm_hints{
+        KeyHint{"y", "confirm"},
+        KeyHint{"n", "cancel"},
+        KeyHint{"Esc", "cancel"},
+    };
+    const auto controls = render_hints(confirm_hints, inner, state.ansi);
     const int question_line = std::max(1, height / 2 - 1);
     std::ostringstream output;
     output << border({inner}, "┌", "", "┐") << '\n';
@@ -446,7 +532,6 @@ std::string delete_confirmation_frame(const ScreenState& state, const CalendarIt
             style = "1;31";
         } else if (line == question_line + 2) {
             content = controls;
-            style = "7";
         } else if (!state.notification.empty() && line == question_line + 3) {
             content = fit_text(" " + printable_text(state.notification, true), inner);
             style = state.notification_is_error ? "1;31" : "1;32";
@@ -531,19 +616,23 @@ std::string search_frame(const ScreenState& state) {
 
     if (state.search_prompt) {
         if (height > 1) lines.push_back(fit_text("/ " + printable_text(state.search_query) + "_",
-                                                 width, false));
+                                                  width, false));
         if (height > 2) lines.push_back(styled(fit_text(
             "Search title, description, location, or calendar ID", width), "2", state.ansi));
-        if (height > 3) lines.push_back(styled(fit_text(
-            "Enter search   Backspace edit   Esc cancel", width), "2", state.ansi));
+        const std::array prompt_hints{
+            KeyHint{"Enter", "search"},
+            KeyHint{"Backspace", "edit"},
+            KeyHint{"Esc", "cancel"},
+        };
+        if (height > 3) lines.push_back(render_hints(prompt_hints, width, state.ansi));
     } else {
         const auto count = state.search_results.size();
         const auto summary = count == 0
-                               ? "No matches for “" + printable_text(state.search_query) + "”"
-                               : std::to_string(count) + (count == 1 ? " match for “" : " matches for “") +
-                                     printable_text(state.search_query) + "”";
+                                ? "No matches for “" + printable_text(state.search_query) + "”"
+                                : std::to_string(count) + (count == 1 ? " match for “" : " matches for “") +
+                                      printable_text(state.search_query) + "”";
         if (height > 1) lines.push_back(styled(fit_text(summary, width), count == 0 ? "1" : "1;36",
-                                               state.ansi));
+                                                state.ansi));
         const auto row_capacity = static_cast<std::size_t>(std::max(0, height - 4));
         std::size_t first = 0;
         if (row_capacity > 0 && state.search_result_index >= row_capacity) {
@@ -568,8 +657,13 @@ std::string search_frame(const ScreenState& state) {
         }
         if (height > 2) lines.push_back(styled(fit_text(
             "Five years either side of the selected date", width), "2", state.ansi));
-        if (height > 1) lines.push_back(styled(fit_text(
-            "↑/↓ choose   Enter jump   / new search   Esc close", width), "2", state.ansi));
+        const std::array results_hints{
+            KeyHint{"↑↓", "choose"},
+            KeyHint{"Enter", "jump"},
+            KeyHint{"/", "new search"},
+            KeyHint{"Esc", "close"},
+        };
+        if (height > 1) lines.push_back(render_hints(results_hints, width, state.ansi));
     }
 
     while (static_cast<int>(lines.size()) < height) {
@@ -602,7 +696,7 @@ std::string agenda_frame(const ScreenState& state) {
     std::vector<std::size_t> ordered(state.agenda_items.size());
     for (std::size_t index = 0; index < ordered.size(); ++index) ordered[index] = index;
     std::stable_sort(ordered.begin(), ordered.end(), [&](const auto left_index,
-                                                         const auto right_index) {
+                                                          const auto right_index) {
         const auto& left = state.agenda_items[left_index];
         const auto& right = state.agenda_items[right_index];
         if (left.day != right.day) return sys_days{left.day} < sys_days{right.day};
@@ -611,13 +705,13 @@ std::string agenda_frame(const ScreenState& state) {
                right.time_of_day.value_or(minutes{-1});
     });
 
-    const auto footer_rows = std::min(2, std::max(0, height - 2));
+    const auto footer_rows = 1;
     const auto row_capacity = static_cast<std::size_t>(
         std::max(0, height - 2 - footer_rows));
     const auto selected = std::find(ordered.begin(), ordered.end(), state.agenda_index);
     const auto selected_position = selected == ordered.end()
-                                     ? std::size_t{0}
-                                     : static_cast<std::size_t>(selected - ordered.begin());
+                                      ? std::size_t{0}
+                                      : static_cast<std::size_t>(selected - ordered.begin());
     std::size_t first = 0;
     if (row_capacity > 0 && selected != ordered.end() && selected_position >= row_capacity) {
         first = selected_position - row_capacity + 1;
@@ -645,13 +739,15 @@ std::string agenda_frame(const ScreenState& state) {
         lines.emplace_back(static_cast<std::size_t>(width), ' ');
     }
     if (footer_rows > 0) {
-        lines.push_back(styled(fit_text(
-            "arrows/jk/Tab choose  Enter month  n/p 6 weeks",
-            width), "2", state.ansi));
-    }
-    if (footer_rows > 1) {
-        lines.push_back(styled(fit_text(
-            "c calendars  / search  g/Esc close", width), "2", state.ansi));
+        const std::array agenda_hints{
+            KeyHint{"↑↓", "choose"},
+            KeyHint{"Enter", "month"},
+            KeyHint{"n/p", "window"},
+            KeyHint{"/", "search"},
+            KeyHint{"c", "calendars"},
+            KeyHint{"g", "close"},
+        };
+        lines.push_back(render_hints(agenda_hints, width, state.ansi));
     }
     while (static_cast<int>(lines.size()) < height) {
         lines.emplace_back(static_cast<std::size_t>(width), ' ');
@@ -703,8 +799,12 @@ std::string calendar_picker_frame(const std::span<const Calendar> calendars,
         lines.emplace_back(static_cast<std::size_t>(width), ' ');
     }
     if (height > 1) {
-        lines.push_back(styled(fit_text(
-            "↑/↓ choose   Enter toggle   c/Esc close", width), "2", state.ansi));
+        const std::array picker_hints{
+            KeyHint{"↑↓", "choose"},
+            KeyHint{"Enter", "toggle"},
+            KeyHint{"c", "close"},
+        };
+        lines.push_back(render_hints(picker_hints, width, state.ansi));
     }
     while (static_cast<int>(lines.size()) < height) {
         lines.emplace_back(static_cast<std::size_t>(width), ' ');
@@ -719,6 +819,118 @@ std::string calendar_picker_frame(const std::span<const Calendar> calendars,
     return output.str();
 }
 
+struct HelpLine {
+    std::string plain; // exact cell accounting
+    std::string rich;  // styled; identical layout when ANSI is disabled
+};
+
+std::string help_frame(const ScreenState& state) {
+    const int width = std::max(1, state.width);
+    const int height = std::max(1, state.height);
+
+    struct HelpGroup {
+        std::string_view title;
+        std::vector<std::pair<std::string_view, std::string_view>> rows;
+    };
+    const std::array groups{
+        HelpGroup{"NAVIGATE",
+                  {{"arrows / hjkl", "Move between days"},
+                   {"PgUp/PgDn or n/p", "Change month"},
+                   {"t", "Jump to today"},
+                   {"Tab / Shift-Tab", "Focus appointments"},
+                   {"Enter", "Read focused appointment"}}},
+        HelpGroup{"APPOINTMENTS",
+                  {{"a", "Add appointment"},
+                   {"e", "Edit focused appointment"},
+                   {"d", "Delete focused appointment"},
+                   {"u", "Undo last change"},
+                   {"Ctrl-R", "Redo last change"}}},
+        HelpGroup{"VIEWS",
+                  {{"g", "Agenda (42 days)"},
+                   {"c", "Calendar visibility"},
+                   {"/", "Search appointments"}}},
+        HelpGroup{"GENERAL",
+                  {{"?", "Toggle this help"}, {"Esc", "Back / close"}, {"q", "Quit"}}},
+    };
+
+    int key_column = 0;
+    for (const auto& group : groups) {
+        for (const auto& [key, description] : group.rows) {
+            key_column = std::max(key_column, display_width(key));
+        }
+    }
+
+    const auto make_column = [&](const std::span<const HelpGroup> column_groups,
+                                 const int column_width) {
+        std::vector<HelpLine> column;
+        for (const auto& group : column_groups) {
+            const std::string title{group.title};
+            column.push_back({title, styled(title, "2;1", state.ansi)});
+            for (const auto& [key, description] : group.rows) {
+                std::string padded_key{key};
+                padded_key.append(static_cast<std::size_t>(key_column - display_width(key)),
+                                  ' ');
+                const int description_budget = std::max(0, column_width - 3 - key_column);
+                const std::string fitted = fit_text(description, description_budget);
+                column.push_back({"  " + padded_key + " " + fitted,
+                                  "  " + styled(padded_key, "1", state.ansi) + " " + fitted});
+            }
+        }
+        return column;
+    };
+
+    std::vector<HelpLine> content;
+    if (width >= 72) {
+        const int column_width = (width - 4) / 2;
+        auto left = make_column(std::span{groups}.subspan(0, 2), column_width);
+        auto right = make_column(std::span{groups}.subspan(2, 2), column_width);
+        const HelpLine blank{std::string(static_cast<std::size_t>(column_width), ' '),
+                             std::string(static_cast<std::size_t>(column_width), ' ')};
+        const auto rows = std::max(left.size(), right.size());
+        left.resize(rows, blank);
+        right.resize(rows, blank);
+        content.reserve(rows);
+        for (std::size_t row = 0; row < rows; ++row) {
+            content.push_back({left[row].plain + "    " + right[row].plain,
+                               left[row].rich + "    " + right[row].rich});
+        }
+    } else {
+        content = make_column(std::span{groups}, width);
+    }
+
+    std::vector<std::string> lines;
+    lines.reserve(static_cast<std::size_t>(height));
+    lines.push_back(styled(centred("KEYBOARD SHORTCUTS", width), "1", state.ansi));
+    if (height > 2) lines.emplace_back(static_cast<std::size_t>(width), ' ');
+    const int content_budget = std::max(0, height - static_cast<int>(lines.size()) - 1);
+    if (static_cast<int>(content.size()) > content_budget) {
+        content.resize(static_cast<std::size_t>(content_budget));
+    }
+    for (const auto& [plain, rich] : content) {
+        std::string line = rich;
+        const int plain_width = display_width(plain);
+        if (plain_width < width) {
+            line.append(static_cast<std::size_t>(width - plain_width), ' ');
+        }
+        lines.push_back(std::move(line));
+    }
+    while (static_cast<int>(lines.size()) < height - 1) {
+        lines.emplace_back(static_cast<std::size_t>(width), ' ');
+    }
+    if (height > 1) {
+        const std::array close_hints{KeyHint{"?", "close"}, KeyHint{"Esc", "close"}};
+        lines.push_back(status_bar("", {}, close_hints, width, state.ansi));
+    }
+    if (static_cast<int>(lines.size()) > height) lines.resize(static_cast<std::size_t>(height));
+
+    std::ostringstream output;
+    for (int line = 0; line < height; ++line) {
+        if (line != 0) output << '\n';
+        output << lines[static_cast<std::size_t>(line)];
+    }
+    return output.str();
+}
+
 std::string compact_frame(std::span<const CalendarItem> items, const ScreenState& state) {
     const int width = std::max(1, state.width);
     const int height = std::max(1, state.height);
@@ -773,18 +985,25 @@ std::string compact_frame(std::span<const CalendarItem> items, const ScreenState
     while (static_cast<int>(lines.size()) < height - 1) {
         lines.emplace_back(static_cast<std::size_t>(width), ' ');
     }
-    std::string controls;
-    if (!state.notification.empty()) {
-        controls = printable_text(state.notification, true);
-    } else if (focused == nullptr) {
-        controls = "g agenda  c calendars  / search  a add  u undo  Ctrl-R redo  ? help  n/p month  t today  q quit";
-    } else {
-        controls = "Tab appointment  Enter open  / search  e edit  d delete  u undo  Ctrl-R redo";
-    }
     if (static_cast<int>(lines.size()) < height) {
-        const auto style = state.notification.empty() ? "2"
-                           : state.notification_is_error ? "1;31" : "1;32";
-        lines.push_back(styled(fit_text(controls, width), style, state.ansi));
+        if (!state.notification.empty()) {
+            const auto text = (state.notification_is_error ? std::string{"! "} : std::string{"✓ "}) +
+                              printable_text(state.notification, true);
+            lines.push_back(styled(fit_text(text, width),
+                                   state.notification_is_error ? "1;31" : "1;32", state.ansi));
+        } else if (focused == nullptr) {
+            const std::array no_focus_hints{
+                KeyHint{"g", "agenda"}, KeyHint{"c", "cals"},  KeyHint{"/", "search"},
+                KeyHint{"a", "add"},    KeyHint{"?", "help"},  KeyHint{"q", "quit"},
+            };
+            lines.push_back(render_hints(no_focus_hints, width, state.ansi));
+        } else {
+            const std::array focus_hints{
+                KeyHint{"Tab", "appt"}, KeyHint{"Enter", "open"},
+                KeyHint{"e", "edit"},   KeyHint{"d", "del"},
+            };
+            lines.push_back(render_hints(focus_hints, width, state.ansi));
+        }
     }
     if (static_cast<int>(lines.size()) > height) lines.resize(static_cast<std::size_t>(height));
 
@@ -848,6 +1067,9 @@ std::string render_month(std::span<const CalendarItem> items, const ScreenState&
     if (state.width < 35 || state.height < 16) {
         return compact_frame(items, state);
     }
+    if (state.show_help) {
+        return help_frame(state);
+    }
 
     const int width = state.width;
     const int inner_total = width - 8; // eight vertical border glyphs
@@ -875,16 +1097,25 @@ std::string render_month(std::span<const CalendarItem> items, const ScreenState&
     }
 
     const auto month_index = static_cast<unsigned>(state.visible_month.month()) - 1;
-    const auto title = "‹  " + std::string{month_names[month_index]} + "  " +
-                       std::to_string(static_cast<int>(state.visible_month.year())) + "  ›";
+    const auto month_title = std::string{month_names[month_index]} + " " +
+                             std::to_string(static_cast<int>(state.visible_month.year()));
+    const auto plain_title = "‹  " + month_title + "  ›";
+    const int title_width = display_width(plain_title);
+    const int title_pad = std::max(0, (width - title_width) / 2);
     std::ostringstream output;
-    output << styled(centred(title, width), "1", state.ansi) << '\n';
+    output << std::string(static_cast<std::size_t>(title_pad), ' ')
+           << styled("‹", "2", state.ansi) << "  " << styled(month_title, "1", state.ansi)
+           << "  " << styled("›", "2", state.ansi);
+    if (title_pad + title_width < width) {
+        output << std::string(static_cast<std::size_t>(width - title_pad - title_width), ' ');
+    }
+    output << '\n';
     output << ' ';
     for (std::size_t column = 0; column < widths.size(); ++column) {
         const auto name_index = weekday_name_index(state.week_start, column);
         const auto name = widths[column] >= 9 ? weekday_long[name_index]
                                               : weekday_short[name_index];
-        output << styled(centred(name, widths[column]), "2;1", state.ansi);
+        output << styled(centred(name, widths[column]), "2", state.ansi);
         output << (column + 1 == widths.size() ? ' ' : ' ');
     }
     output << '\n' << border(widths, "┌", "┬", "┐") << '\n';
@@ -956,26 +1187,54 @@ std::string render_month(std::span<const CalendarItem> items, const ScreenState&
 
     const auto selected_count = by_day.contains(sys_days{state.selected_day})
                                     ? by_day.at(sys_days{state.selected_day}).size() : 0U;
-    std::string status;
-    if (state.show_help) {
-        status = " arrows/hjkl day  Tab/⇧Tab appointment  Enter read  g agenda  c calendars  / search  a add  e edit  d delete  u undo  Ctrl-R redo  n/p month  t today  ? close  q quit";
-    } else if (!state.notification.empty()) {
-        status = " " + printable_text(state.notification, true);
+    
+    // Status left, priority-ordered key hints right.
+    const auto friendly_day = [](const year_month_day value) {
+        return std::string{weekday_short[weekday{sys_days{value}}.iso_encoding() - 1]} + ", " +
+               std::to_string(static_cast<unsigned>(value.day())) + " " +
+               std::string{month_short[static_cast<unsigned>(value.month()) - 1]} + " " +
+               std::to_string(static_cast<int>(value.year()));
+    };
+    std::vector<KeyHint> hints;
+    std::string left_status;
+    std::string status_style;
+
+    if (!state.notification.empty()) {
+        left_status = (state.notification_is_error ? "! " : "✓ ") +
+                      printable_text(state.notification, true);
+        status_style = state.notification_is_error ? "1;31" : "1;32";
     } else if (focused != nullptr) {
         const auto focus_title = focused->title.empty() ? std::string{"(untitled)"}
                                                         : printable_text(focused->title);
-        status = " " + iso_date(state.selected_day) + "  " +
-                 focus_title + "   Tab next   Enter read   / search   e edit   d delete   u undo   Ctrl-R redo";
+        left_status = friendly_day(state.selected_day) + " · " + focus_title;
+        hints = {{
+            {"Tab", "next"},
+            {"Enter", "read"},
+            {"e", "edit"},
+            {"d", "del"},
+            {"u", "undo"},
+            {"?", "help"},
+        }};
     } else {
-        status = " " + iso_date(state.selected_day) + "  " + std::to_string(selected_count) +
-                 (selected_count == 1 ? " appointment" : " appointments") +
-                 (selected_count > 0 ? "   Tab focus" : "") +
-                 "   g agenda   c calendars   / search   a add   u undo   Ctrl-R redo   ? help   q quit";
+        left_status = friendly_day(state.selected_day) + " · " +
+                      std::to_string(selected_count) +
+                      (selected_count == 1 ? " appointment" : " appointments");
+        if (selected_count > 0) {
+            hints = {{"Tab", "focus"}};
+        }
+        const std::array right_hints_no_focus{
+            KeyHint{"a", "add"},
+            KeyHint{"g", "agenda"},
+            KeyHint{"c", "calendars"},
+            KeyHint{"/", "search"},
+            KeyHint{"u", "undo"},
+            KeyHint{"?", "help"},
+            KeyHint{"q", "quit"},
+        };
+        hints.insert(hints.end(), right_hints_no_focus.begin(), right_hints_no_focus.end());
     }
-    const auto status_style = !state.notification.empty()
-                                ? (state.notification_is_error ? "1;31" : "1;32")
-                                : focused != nullptr ? "7" : "2";
-    output << styled(fit_text(status, width), status_style, state.ansi);
+
+    output << status_bar(left_status, status_style, hints, width, state.ansi);
     return output.str();
 }
 

tests/editor_tests.cpp

@@ -47,6 +47,10 @@ void test_create_and_validation()
     check(editor.handle_key("\x13") == nocal::tui::EditorOutcome::active &&
               editor.focused_field() == nocal::tui::EditorField::title && !editor.error().empty(),
           "blank title blocks submission and focuses the invalid field");
+    check(editor.render(72, 18, true).find("\x1b[1;31m") != std::string::npos,
+          "validation errors render in the error style");
+    check(editor.render(72, 18, false).find("\x1b[") == std::string::npos,
+          "error frame stays plain with ANSI disabled");
 
     (void)editor.handle_key("Design review");
     focus(editor, nocal::tui::EditorField::end_time);
@@ -179,6 +183,8 @@ void test_rendering()
           "render fills requested height exactly");
     check(plain.find("NEW APPOINTMENT") != std::string::npos &&
               plain.find("Ctrl-S save") != std::string::npos &&
+              plain.find("Tab next field") != std::string::npos &&
+              plain.find("Esc cancel") != std::string::npos &&
               plain.find("[ ] timed appointment") != std::string::npos,
           "render exposes form identity and controls");
     check(plain.find("\x1b[") == std::string::npos, "ANSI can be disabled");

tests/microsoft_account_tests.cpp

@@ -0,0 +1,886 @@
+#include "nocal/storage/sync_cache.hpp"
+#include "nocal/sync/microsoft_account.hpp"
+#include "nocal/sync/microsoft_graph.hpp"
+#include "nocal/sync/oauth.hpp"
+#include "nocal/sync/oauth_tokens.hpp"
+#include "nocal/sync/secret_store.hpp"
+
+#include <cstdint>
+#include <cstdlib>
+#include <exception>
+#include <filesystem>
+#include <functional>
+#include <iostream>
+#include <map>
+#include <optional>
+#include <span>
+#include <stdexcept>
+#include <string>
+#include <string_view>
+#include <vector>
+
+namespace {
+
+using nocal::storage::CachedAccount;
+using nocal::storage::SyncCache;
+using nocal::sync::AuthorizationCallback;
+using nocal::sync::AuthorizationCallbackReceiver;
+using nocal::sync::BrowserLauncher;
+using nocal::sync::EntropySource;
+using nocal::sync::HttpMethod;
+using nocal::sync::HttpRequest;
+using nocal::sync::HttpResponse;
+using nocal::sync::HttpTransport;
+using nocal::sync::MicrosoftAccountError;
+using nocal::sync::OAuthClientConfig;
+using nocal::sync::OAuthSecretStore;
+using nocal::sync::OAuthTokens;
+
+void require(bool condition, std::string_view message) {
+    if (!condition) {
+        throw std::runtime_error(std::string{message});
+    }
+}
+
+// -----------------------------------------------------------------------
+// TempDirectory for a real SyncCache
+// -----------------------------------------------------------------------
+class TempDirectory {
+public:
+    TempDirectory() {
+        std::string pattern =
+            (std::filesystem::temp_directory_path() / "nocal-microsoft-account-tests.XXXXXX")
+                .string();
+        std::vector<char> writable(pattern.begin(), pattern.end());
+        writable.push_back('\0');
+        const char* created = ::mkdtemp(writable.data());
+        if (created == nullptr) {
+            throw std::runtime_error("mkdtemp failed");
+        }
+        path_ = created;
+    }
+
+    TempDirectory(const TempDirectory&) = delete;
+    TempDirectory& operator=(const TempDirectory&) = delete;
+
+    ~TempDirectory() {
+        std::error_code ignored;
+        std::filesystem::remove_all(path_, ignored);
+    }
+
+    [[nodiscard]] const std::filesystem::path& path() const noexcept { return path_; }
+
+private:
+    std::filesystem::path path_;
+};
+
+// -----------------------------------------------------------------------
+// ScriptedEntropy – fixed deterministic values
+// -----------------------------------------------------------------------
+class ScriptedEntropy final : public EntropySource {
+public:
+    explicit ScriptedEntropy(std::vector<std::array<std::byte, 32>> scripted_values)
+        : values(std::move(scripted_values)) {}
+
+    std::vector<std::array<std::byte, 32>> values;
+    std::size_t calls{0};
+
+    void fill(std::span<std::byte> output) override {
+        require(output.size() == 32, "entropy request was not exactly 32 bytes");
+        const std::size_t call = calls++;
+        require(call < values.size(), "unexpected entropy request");
+        std::copy(values[call].begin(), values[call].end(), output.begin());
+    }
+};
+
+// -----------------------------------------------------------------------
+// ScriptedBrowser
+// -----------------------------------------------------------------------
+class ScriptedBrowser final : public BrowserLauncher {
+public:
+    std::vector<std::string> urls;
+
+    void open(const std::string& url) override { urls.push_back(url); }
+};
+
+// -----------------------------------------------------------------------
+// ScriptedReceiver – copies state from browser URL if needed
+// -----------------------------------------------------------------------
+class ScriptedReceiver final : public AuthorizationCallbackReceiver {
+public:
+    std::string redirect{"http://127.0.0.1:43123/callback"};
+    AuthorizationCallback callback;
+    std::size_t receives{0};
+    bool copy_browser_state{true};
+    ScriptedBrowser* browser{nullptr};
+
+    [[nodiscard]] std::string redirect_uri() const override { return redirect; }
+
+    AuthorizationCallback receive() override {
+        ++receives;
+        if (copy_browser_state && browser != nullptr && !browser->urls.empty()) {
+            // Extract state from the authorization URL
+            const std::string& url = browser->urls.front();
+            const std::size_t state_pos = url.find("state=");
+            if (state_pos != std::string::npos) {
+                const std::size_t value_start = state_pos + 6;
+                const std::size_t amp = url.find('&', value_start);
+                const std::size_t len = (amp == std::string::npos) ? url.size() - value_start
+                                                                   : amp - value_start;
+                AuthorizationCallback result = callback;
+                result.state = url.substr(value_start, len);
+                return result;
+            }
+        }
+        return callback;
+    }
+};
+
+// -----------------------------------------------------------------------
+// ScriptedTransport – scripted responses for token exchange then /me
+// -----------------------------------------------------------------------
+class ScriptedTransport final : public HttpTransport {
+public:
+    struct ResponseSpec {
+        int status{200};
+        std::string body;
+        bool throw_on_send{false};
+        std::string send_error_message{};
+    };
+
+    std::vector<HttpRequest> requests;
+    std::vector<ResponseSpec> responses;
+
+    HttpResponse send(const HttpRequest& request) override {
+        requests.push_back(request);
+        const std::size_t index = requests.size() - 1;
+        if (index >= responses.size()) {
+            return {200, {}, "{}"};
+        }
+        const ResponseSpec& spec = responses[index];
+        if (spec.throw_on_send) {
+            throw std::runtime_error(spec.send_error_message);
+        }
+        return {spec.status, {}, spec.body};
+    }
+};
+
+// -----------------------------------------------------------------------
+// ScriptedSecretStore – in-memory with injectable store failure
+// -----------------------------------------------------------------------
+class ScriptedSecretStore final : public OAuthSecretStore {
+public:
+    std::map<std::string, OAuthTokens> store_data;
+    bool throw_on_store{false};
+    std::string store_error_message{};
+    std::size_t store_calls{0};
+    std::size_t load_calls{0};
+    std::size_t erase_calls{0};
+
+    void store(std::string account_id, const OAuthTokens& tokens, std::stop_token = {}) override {
+        ++store_calls;
+        if (throw_on_store) {
+            throw std::runtime_error(store_error_message);
+        }
+        store_data[std::move(account_id)] = tokens;
+    }
+
+    [[nodiscard]] std::optional<OAuthTokens> load(
+        std::string account_id, std::stop_token = {}) override {
+        ++load_calls;
+        const auto found = store_data.find(account_id);
+        if (found != store_data.end()) {
+            return found->second;
+        }
+        return std::nullopt;
+    }
+
+    void erase(std::string account_id, std::stop_token = {}) override {
+        ++erase_calls;
+        store_data.erase(account_id);
+    }
+};
+
+// -----------------------------------------------------------------------
+// Controllable clock
+// -----------------------------------------------------------------------
+class ControllableClock {
+public:
+    std::int64_t value{1000};
+
+    [[nodiscard]] std::int64_t operator()() { return value; }
+};
+
+// -----------------------------------------------------------------------
+// Helpers
+// -----------------------------------------------------------------------
+
+[[nodiscard]] std::array<std::byte, 32> zeros() { return {}; }
+
+[[nodiscard]] std::string token_response_body(std::string_view access_token,
+    std::string_view refresh_token, std::int64_t expires_in) {
+    return "{\"access_token\":\"" + std::string(access_token)
+        + "\",\"refresh_token\":\"" + std::string(refresh_token)
+        + "\",\"token_type\":\"Bearer\",\"expires_in\":" + std::to_string(expires_in) + "}";
+}
+
+[[nodiscard]] std::string me_response_body(
+    std::string_view id, std::string_view display_name, std::string_view user_principal_name) {
+    std::string body = "{\"id\":\"" + std::string(id) + "\"";
+    if (!display_name.empty()) {
+        body += ",\"displayName\":\"" + std::string(display_name) + "\"";
+    }
+    if (!user_principal_name.empty()) {
+        body += ",\"userPrincipalName\":\"" + std::string(user_principal_name) + "\"";
+    }
+    body += "}";
+    return body;
+}
+
+// -----------------------------------------------------------------------
+// Test: Happy path
+// -----------------------------------------------------------------------
+void test_happy_path() {
+    TempDirectory temp;
+    SyncCache cache(temp.path() / "cache.db");
+
+    ScriptedEntropy entropy{{zeros(), zeros()}};
+    ScriptedBrowser browser;
+    ScriptedReceiver receiver;
+    receiver.browser = &browser;
+    receiver.callback = {"auth-code", "", "", ""};
+    ScriptedTransport transport;
+    transport.responses.push_back(
+        {200, token_response_body("access-token-value", "refresh-token-value", 3600)});
+    transport.responses.push_back(
+        {200, me_response_body("remote-subject", "Display Name", "user@example.com")});
+    ScriptedSecretStore secret_store;
+    ControllableClock clock;
+
+    OAuthClientConfig config;
+    config.client_id = "test-client-id";
+    config.authorization_endpoint = "https://login.example/auth";
+    config.token_endpoint = "https://login.example/token";
+    config.scopes = {"offline_access", "User.Read", "Calendars.Read"};
+
+    const CachedAccount account = nocal::sync::connect_microsoft_account(
+        config, browser, receiver, transport, entropy, secret_store, cache,
+        [&clock]() { return clock(); });
+
+    // Verify returned account
+    require(account.provider == "microsoft-graph", "wrong provider");
+
+    // Compute expected account id
+    const std::string expected_id =
+        nocal::sync::microsoft_account_id("remote-subject");
+    require(account.id == expected_id, "account id mismatch");
+    require(account.remote_subject == "remote-subject", "remote subject mismatch");
+    require(account.display_name == "Display Name", "display name mismatch");
+
+    // Cache snapshot has exactly one account
+    const auto snapshot = cache.snapshot();
+    require(snapshot.accounts.size() == 1, "expected exactly one cached account");
+    require(snapshot.accounts.front() == account, "cached account differs from returned");
+
+    // Secret store holds the parsed tokens under the same id
+    const auto stored_tokens = secret_store.store_data.find(expected_id);
+    require(stored_tokens != secret_store.store_data.end(), "tokens not stored");
+    require(stored_tokens->second.access_token == "access-token-value",
+        "wrong stored access token");
+    require(stored_tokens->second.refresh_token == "refresh-token-value",
+        "wrong stored refresh token");
+    require(stored_tokens->second.token_type == "Bearer", "wrong stored token type");
+
+    // Exactly one browser URL, one token request, one /me GET with Bearer token
+    require(browser.urls.size() == 1, "expected exactly one browser URL");
+    require(transport.requests.size() == 2, "expected exactly two HTTP requests");
+    require(transport.requests[0].method == HttpMethod::post,
+        "first request was not POST (token)");
+    require(transport.requests[0].url == "https://login.example/token",
+        "first request URL mismatch");
+    require(transport.requests[1].method == HttpMethod::get,
+        "second request was not GET (/me)");
+    require(transport.requests[1].url.find("graph.microsoft.com") != std::string::npos,
+        "second request URL does not contain graph.microsoft.com");
+    bool has_bearer = false;
+    for (const auto& header : transport.requests[1].headers) {
+        if (header.name == "Authorization") {
+            has_bearer = header.value.find("Bearer access-token-value") != std::string::npos;
+        }
+    }
+    require(has_bearer, "/me request did not carry Bearer token");
+}
+
+// -----------------------------------------------------------------------
+// Test: Idempotent reconnect
+// -----------------------------------------------------------------------
+void test_idempotent_reconnect() {
+    TempDirectory temp;
+    SyncCache cache(temp.path() / "cache.db");
+
+    auto do_connect = [&]() -> std::string {
+        ScriptedEntropy entropy{{zeros(), zeros()}};
+        ScriptedBrowser browser;
+        ScriptedReceiver receiver;
+        receiver.browser = &browser;
+        receiver.callback = {"auth-code", "", "", ""};
+        ScriptedTransport transport;
+        transport.responses.push_back(
+            {200, token_response_body("access-token-" + std::to_string(transport.requests.size()),
+                 "refresh-token-" + std::to_string(transport.requests.size()), 3600)});
+        transport.responses.push_back(
+            {200, me_response_body("same-subject", "Same User", "same@example.com")});
+        ScriptedSecretStore secret_store;
+        ControllableClock clock;
+
+        OAuthClientConfig config;
+        config.client_id = "test-client-id";
+        config.authorization_endpoint = "https://login.example/auth";
+        config.token_endpoint = "https://login.example/token";
+        config.scopes = {"offline_access", "User.Read", "Calendars.Read"};
+
+        const CachedAccount account = nocal::sync::connect_microsoft_account(
+            config, browser, receiver, transport, entropy, secret_store, cache,
+            [&clock]() { return clock(); });
+        return account.id;
+    };
+
+    const std::string first_id = do_connect();
+    const std::string second_id = do_connect();
+
+    // Same account id
+    require(first_id == second_id, "reconnect produced different account id");
+
+    // Cache still has exactly one account
+    const auto snapshot = cache.snapshot();
+    require(snapshot.accounts.size() == 1, "expected exactly one account after reconnect");
+    require(snapshot.accounts.front().id == first_id, "account id mismatch in cache");
+}
+
+// -----------------------------------------------------------------------
+// Test: Authorization rejected
+// -----------------------------------------------------------------------
+void test_authorization_rejected() {
+    TempDirectory temp;
+    SyncCache cache(temp.path() / "cache.db");
+
+    ScriptedEntropy entropy{{zeros(), zeros()}};
+    ScriptedBrowser browser;
+    ScriptedReceiver receiver;
+    receiver.browser = &browser;
+    receiver.callback = {"", "", "access_denied", ""};
+    ScriptedTransport transport;
+    ScriptedSecretStore secret_store;
+    ControllableClock clock;
+
+    OAuthClientConfig config;
+    config.client_id = "test-client-id";
+    config.authorization_endpoint = "https://login.example/auth";
+    config.token_endpoint = "https://login.example/token";
+    config.scopes = {"offline_access", "User.Read", "Calendars.Read"};
+
+    bool caught = false;
+    try {
+        (void)nocal::sync::connect_microsoft_account(
+            config, browser, receiver, transport, entropy, secret_store, cache,
+            [&clock]() { return clock(); });
+    } catch (const MicrosoftAccountError& e) {
+        caught = true;
+        require(std::string(e.what()) == "Microsoft authorization failed",
+            "wrong error message on authorization rejection");
+    } catch (const std::exception& e) {
+        throw std::runtime_error(
+            std::string("wrong exception type: ") + e.what());
+    }
+    require(caught, "expected MicrosoftAccountError");
+
+    // Cache and secret store both untouched
+    require(cache.snapshot().accounts.empty(), "cache was modified on authorization rejection");
+    require(secret_store.store_calls == 0, "secret store was called on authorization rejection");
+}
+
+// -----------------------------------------------------------------------
+// Test: Token endpoint returns non-2xx
+// -----------------------------------------------------------------------
+void test_token_endpoint_non2xx() {
+    TempDirectory temp;
+    SyncCache cache(temp.path() / "cache.db");
+
+    ScriptedEntropy entropy{{zeros(), zeros()}};
+    ScriptedBrowser browser;
+    ScriptedReceiver receiver;
+    receiver.browser = &browser;
+    receiver.callback = {"auth-code", "", "", ""};
+    ScriptedTransport transport;
+    transport.responses.push_back({400, "{\"error\":\"invalid_grant\"}"});
+    ScriptedSecretStore secret_store;
+    ControllableClock clock;
+
+    OAuthClientConfig config;
+    config.client_id = "test-client-id";
+    config.authorization_endpoint = "https://login.example/auth";
+    config.token_endpoint = "https://login.example/token";
+    config.scopes = {"offline_access", "User.Read", "Calendars.Read"};
+
+    bool caught = false;
+    try {
+        (void)nocal::sync::connect_microsoft_account(
+            config, browser, receiver, transport, entropy, secret_store, cache,
+            [&clock]() { return clock(); });
+    } catch (const MicrosoftAccountError& e) {
+        caught = true;
+        require(std::string(e.what()) == "Microsoft authorization failed",
+            "wrong error message on token rejection");
+    }
+    require(caught, "expected MicrosoftAccountError");
+
+    // Nothing stored
+    require(cache.snapshot().accounts.empty(), "cache was modified on token error");
+    require(secret_store.store_calls == 0, "secret store was called on token error");
+}
+
+// -----------------------------------------------------------------------
+// Test: Token response missing refresh_token
+// -----------------------------------------------------------------------
+void test_token_response_missing_refresh() {
+    TempDirectory temp;
+    SyncCache cache(temp.path() / "cache.db");
+
+    ScriptedEntropy entropy{{zeros(), zeros()}};
+    ScriptedBrowser browser;
+    ScriptedReceiver receiver;
+    receiver.browser = &browser;
+    receiver.callback = {"auth-code", "", "", ""};
+    ScriptedTransport transport;
+    // No refresh_token in response — parse_oauth_token_response will reject
+    transport.responses.push_back(
+        {200, "{\"access_token\":\"acc\",\"token_type\":\"Bearer\",\"expires_in\":3600}"});
+    ScriptedSecretStore secret_store;
+    ControllableClock clock;
+
+    OAuthClientConfig config;
+    config.client_id = "test-client-id";
+    config.authorization_endpoint = "https://login.example/auth";
+    config.token_endpoint = "https://login.example/token";
+    config.scopes = {"offline_access", "User.Read", "Calendars.Read"};
+
+    bool caught = false;
+    try {
+        (void)nocal::sync::connect_microsoft_account(
+            config, browser, receiver, transport, entropy, secret_store, cache,
+            [&clock]() { return clock(); });
+    } catch (const MicrosoftAccountError& e) {
+        caught = true;
+        require(std::string(e.what()) == "Microsoft token response invalid",
+            "wrong error message on missing refresh token");
+    }
+    require(caught, "expected MicrosoftAccountError");
+
+    // Nothing stored
+    require(cache.snapshot().accounts.empty(), "cache was modified on parse error");
+    require(secret_store.store_calls == 0, "secret store was called on parse error");
+}
+
+// -----------------------------------------------------------------------
+// Test: /me failure
+// -----------------------------------------------------------------------
+void test_me_failure() {
+    TempDirectory temp;
+    SyncCache cache(temp.path() / "cache.db");
+
+    ScriptedEntropy entropy{{zeros(), zeros()}};
+    ScriptedBrowser browser;
+    ScriptedReceiver receiver;
+    receiver.browser = &browser;
+    receiver.callback = {"auth-code", "", "", ""};
+    ScriptedTransport transport;
+    // Successful token response
+    transport.responses.push_back(
+        {200, token_response_body("acc-token", "ref-token", 3600)});
+    // /me returns garbage (malformed JSON)
+    transport.responses.push_back({200, "not-valid-json"});
+    ScriptedSecretStore secret_store;
+    ControllableClock clock;
+
+    OAuthClientConfig config;
+    config.client_id = "test-client-id";
+    config.authorization_endpoint = "https://login.example/auth";
+    config.token_endpoint = "https://login.example/token";
+    config.scopes = {"offline_access", "User.Read", "Calendars.Read"};
+
+    bool caught = false;
+    try {
+        (void)nocal::sync::connect_microsoft_account(
+            config, browser, receiver, transport, entropy, secret_store, cache,
+            [&clock]() { return clock(); });
+    } catch (const MicrosoftAccountError& e) {
+        caught = true;
+        require(std::string(e.what()) == "Microsoft identity read failed",
+            "wrong error message on /me failure");
+    }
+    require(caught, "expected MicrosoftAccountError");
+
+    // Cache and secret store untouched
+    require(cache.snapshot().accounts.empty(), "cache was modified on /me failure");
+    require(secret_store.store_calls == 0, "secret store was called on /me failure");
+}
+
+// -----------------------------------------------------------------------
+// Test: Secret-store store() failure — cache retains the account row
+// -----------------------------------------------------------------------
+void test_secret_store_failure() {
+    TempDirectory temp;
+    SyncCache cache(temp.path() / "cache.db");
+
+    ScriptedEntropy entropy{{zeros(), zeros()}};
+    ScriptedBrowser browser;
+    ScriptedReceiver receiver;
+    receiver.browser = &browser;
+    receiver.callback = {"auth-code", "", "", ""};
+    ScriptedTransport transport;
+    transport.responses.push_back(
+        {200, token_response_body("acc-token", "ref-token", 3600)});
+    transport.responses.push_back(
+        {200, me_response_body("remote-subject", "Display Name", "user@example.com")});
+    ScriptedSecretStore secret_store;
+    secret_store.throw_on_store = true;
+    secret_store.store_error_message = "secret service unavailable";
+    ControllableClock clock;
+
+    OAuthClientConfig config;
+    config.client_id = "test-client-id";
+    config.authorization_endpoint = "https://login.example/auth";
+    config.token_endpoint = "https://login.example/token";
+    config.scopes = {"offline_access", "User.Read", "Calendars.Read"};
+
+    bool caught = false;
+    try {
+        (void)nocal::sync::connect_microsoft_account(
+            config, browser, receiver, transport, entropy, secret_store, cache,
+            [&clock]() { return clock(); });
+    } catch (const MicrosoftAccountError& e) {
+        caught = true;
+        require(std::string(e.what()) == "credential storage failed",
+            "wrong error message on store failure");
+    }
+    require(caught, "expected MicrosoftAccountError");
+
+    // Cache DOES retain the account row (documented disconnected state)
+    const auto snapshot = cache.snapshot();
+    require(snapshot.accounts.size() == 1,
+        "cache should retain the account row even when secret store fails");
+    require(snapshot.accounts.front().remote_subject == "remote-subject",
+        "cached account has wrong remote subject");
+
+    // Verify secret store does NOT have the credentials
+    const std::string expected_id =
+        nocal::sync::microsoft_account_id("remote-subject");
+    const auto stored = secret_store.store_data.find(expected_id);
+    require(stored == secret_store.store_data.end(),
+        "secret store should not contain credentials after store failure");
+    require(secret_store.store_calls == 1, "store should have been attempted once");
+
+    // A subsequent successful connect should complete (idempotent)
+    ScriptedEntropy entropy2{{zeros(), zeros()}};
+    ScriptedBrowser browser2;
+    ScriptedReceiver receiver2;
+    receiver2.browser = &browser2;
+    receiver2.callback = {"auth-code-2", "", "", ""};
+    ScriptedTransport transport2;
+    transport2.responses.push_back(
+        {200, token_response_body("acc-token-2", "ref-token-2", 3600)});
+    transport2.responses.push_back(
+        {200, me_response_body("remote-subject", "Display Name", "user@example.com")});
+    ScriptedSecretStore secret_store2;
+    ControllableClock clock2;
+
+    const CachedAccount retry_account = nocal::sync::connect_microsoft_account(
+        config, browser2, receiver2, transport2, entropy2, secret_store2, cache,
+        [&clock2]() { return clock2(); });
+    require(retry_account.id == expected_id,
+        "retry account id should match deterministic id");
+    require(cache.snapshot().accounts.size() == 1,
+        "cache should still have exactly one account after successful retry");
+
+    const auto stored2 = secret_store2.store_data.find(expected_id);
+    require(stored2 != secret_store2.store_data.end(),
+        "credentials should be stored after successful retry");
+}
+
+// -----------------------------------------------------------------------
+// Test: Empty displayName falls back to userPrincipalName
+// -----------------------------------------------------------------------
+void test_empty_display_name_fallback() {
+    TempDirectory temp;
+    SyncCache cache(temp.path() / "cache.db");
+
+    ScriptedEntropy entropy{{zeros(), zeros()}};
+    ScriptedBrowser browser;
+    ScriptedReceiver receiver;
+    receiver.browser = &browser;
+    receiver.callback = {"auth-code", "", "", ""};
+    ScriptedTransport transport;
+    transport.responses.push_back(
+        {200, token_response_body("acc-token", "ref-token", 3600)});
+    // No displayName in /me response
+    transport.responses.push_back(
+        {200, me_response_body("remote-subject", "", "fallback@example.com")});
+    ScriptedSecretStore secret_store;
+    ControllableClock clock;
+
+    OAuthClientConfig config;
+    config.client_id = "test-client-id";
+    config.authorization_endpoint = "https://login.example/auth";
+    config.token_endpoint = "https://login.example/token";
+    config.scopes = {"offline_access", "User.Read", "Calendars.Read"};
+
+    const CachedAccount account = nocal::sync::connect_microsoft_account(
+        config, browser, receiver, transport, entropy, secret_store, cache,
+        [&clock]() { return clock(); });
+
+    require(account.display_name == "fallback@example.com",
+        "display name should fall back to userPrincipalName");
+}
+
+// -----------------------------------------------------------------------
+// Test: default_microsoft_client_id with env unset and set
+// -----------------------------------------------------------------------
+void test_default_client_id() {
+    // Save original env state and unset
+    const char* original = std::getenv("NOCAL_MICROSOFT_CLIENT_ID");
+
+    // Test with env unset
+    if (original != nullptr) {
+        ::unsetenv("NOCAL_MICROSOFT_CLIENT_ID");
+    }
+    const std::string unset_result = nocal::sync::default_microsoft_client_id();
+    require(unset_result == nocal::sync::microsoft_client_id_placeholder,
+        "default client id should be placeholder when env is unset");
+
+    // Test with env set
+    ::setenv("NOCAL_MICROSOFT_CLIENT_ID", "my-test-client-id", 1);
+    const std::string set_result = nocal::sync::default_microsoft_client_id();
+    require(set_result == "my-test-client-id",
+        "default client id should match env when set");
+
+    // Restore original
+    if (original != nullptr) {
+        ::setenv("NOCAL_MICROSOFT_CLIENT_ID", original, 1);
+    } else {
+        ::unsetenv("NOCAL_MICROSOFT_CLIENT_ID");
+    }
+}
+
+// -----------------------------------------------------------------------
+// Test: microsoft_oauth_config
+// -----------------------------------------------------------------------
+void test_microsoft_oauth_config() {
+    const OAuthClientConfig config = nocal::sync::microsoft_oauth_config("my-client-id");
+
+    require(config.client_id == "my-client-id", "client_id mismatch");
+    require(config.authorization_endpoint
+            == "https://login.microsoftonline.com/common/oauth2/v2.0/authorize",
+        "wrong authorization endpoint");
+    require(config.token_endpoint
+            == "https://login.microsoftonline.com/common/oauth2/v2.0/token",
+        "wrong token endpoint");
+
+    require(config.scopes.size() == 3, "expected exactly 3 scopes");
+    require(config.scopes[0] == "offline_access", "scope[0] mismatch");
+    require(config.scopes[1] == "User.Read", "scope[1] mismatch");
+    require(config.scopes[2] == "Calendars.Read", "scope[2] mismatch");
+}
+
+// -----------------------------------------------------------------------
+// Test: Error messages never contain credential material
+// -----------------------------------------------------------------------
+void test_error_message_redaction() {
+    TempDirectory temp;
+    SyncCache cache(temp.path() / "cache.db");
+
+    const std::string access_marker = "ACCESS_CRED_MARKER_12345";
+    const std::string refresh_marker = "REFRESH_CRED_MARKER_67890";
+    const std::string auth_code_marker = "AUTH_CODE_MARKER_ABCDE";
+
+    // Test 1: Token endpoint error (400)
+    {
+        ScriptedEntropy entropy{{zeros(), zeros()}};
+        ScriptedBrowser browser;
+        ScriptedReceiver receiver;
+        receiver.browser = &browser;
+        receiver.callback = {auth_code_marker, "", "", ""};
+        ScriptedTransport transport;
+        transport.responses.push_back({400, access_marker + refresh_marker});
+        ScriptedSecretStore secret_store;
+        ControllableClock clock;
+
+        OAuthClientConfig config;
+        config.client_id = "test-client-id";
+        config.authorization_endpoint = "https://login.example/auth";
+        config.token_endpoint = "https://login.example/token";
+        config.scopes = {"offline_access", "User.Read", "Calendars.Read"};
+
+        try {
+            (void)nocal::sync::connect_microsoft_account(
+                config, browser, receiver, transport, entropy, secret_store, cache,
+                [&clock]() { return clock(); });
+        } catch (const std::exception& e) {
+            const std::string msg = e.what();
+            require(msg.find(access_marker) == std::string::npos,
+                "error leaked access token on 400");
+            require(msg.find(refresh_marker) == std::string::npos,
+                "error leaked refresh token on 400");
+            require(msg.find(auth_code_marker) == std::string::npos,
+                "error leaked auth code on 400");
+        }
+    }
+
+    // Test 2: Parse error (missing refresh_token)
+    {
+        ScriptedEntropy entropy{{zeros(), zeros()}};
+        ScriptedBrowser browser;
+        ScriptedReceiver receiver;
+        receiver.browser = &browser;
+        receiver.callback = {auth_code_marker, "", "", ""};
+        ScriptedTransport transport;
+        transport.responses.push_back(
+            {200, "{\"access_token\":\"" + access_marker
+                      + "\",\"token_type\":\"Bearer\",\"expires_in\":3600}"});
+        ScriptedSecretStore secret_store;
+        ControllableClock clock;
+
+        OAuthClientConfig config;
+        config.client_id = "test-client-id";
+        config.authorization_endpoint = "https://login.example/auth";
+        config.token_endpoint = "https://login.example/token";
+        config.scopes = {"offline_access", "User.Read", "Calendars.Read"};
+
+        try {
+            (void)nocal::sync::connect_microsoft_account(
+                config, browser, receiver, transport, entropy, secret_store, cache,
+                [&clock]() { return clock(); });
+        } catch (const std::exception& e) {
+            const std::string msg = e.what();
+            require(msg.find(access_marker) == std::string::npos,
+                "error leaked access token on parse failure");
+            require(msg.find(auth_code_marker) == std::string::npos,
+                "error leaked auth code on parse failure");
+        }
+    }
+
+    // Test 3: /me failure
+    {
+        ScriptedEntropy entropy{{zeros(), zeros()}};
+        ScriptedBrowser browser;
+        ScriptedReceiver receiver;
+        receiver.browser = &browser;
+        receiver.callback = {auth_code_marker, "", "", ""};
+        ScriptedTransport transport;
+        transport.responses.push_back(
+            {200, "{\"access_token\":\"" + access_marker
+                      + "\",\"refresh_token\":\"" + refresh_marker
+                      + "\",\"token_type\":\"Bearer\",\"expires_in\":3600}"});
+        transport.responses.push_back(
+            {200, "{\"bad_field\":" + access_marker + "}"});
+        ScriptedSecretStore secret_store;
+        ControllableClock clock;
+
+        OAuthClientConfig config;
+        config.client_id = "test-client-id";
+        config.authorization_endpoint = "https://login.example/auth";
+        config.token_endpoint = "https://login.example/token";
+        config.scopes = {"offline_access", "User.Read", "Calendars.Read"};
+
+        try {
+            (void)nocal::sync::connect_microsoft_account(
+                config, browser, receiver, transport, entropy, secret_store, cache,
+                [&clock]() { return clock(); });
+        } catch (const std::exception& e) {
+            const std::string msg = e.what();
+            require(msg.find(access_marker) == std::string::npos,
+                "error leaked access token on /me failure");
+            require(msg.find(refresh_marker) == std::string::npos,
+                "error leaked refresh token on /me failure");
+            require(msg.find(auth_code_marker) == std::string::npos,
+                "error leaked auth code on /me failure");
+        }
+    }
+
+    // Test 4: Secret store failure
+    {
+        ScriptedEntropy entropy{{zeros(), zeros()}};
+        ScriptedBrowser browser;
+        ScriptedReceiver receiver;
+        receiver.browser = &browser;
+        receiver.callback = {auth_code_marker, "", "", ""};
+        ScriptedTransport transport;
+        transport.responses.push_back(
+            {200, "{\"access_token\":\"" + access_marker
+                      + "\",\"refresh_token\":\"" + refresh_marker
+                      + "\",\"token_type\":\"Bearer\",\"expires_in\":3600}"});
+        transport.responses.push_back(
+            {200, me_response_body("remote-subject", "Display", "user@example.com")});
+        ScriptedSecretStore secret_store;
+        secret_store.throw_on_store = true;
+        ControllableClock clock;
+
+        OAuthClientConfig config;
+        config.client_id = "test-client-id";
+        config.authorization_endpoint = "https://login.example/auth";
+        config.token_endpoint = "https://login.example/token";
+        config.scopes = {"offline_access", "User.Read", "Calendars.Read"};
+
+        try {
+            (void)nocal::sync::connect_microsoft_account(
+                config, browser, receiver, transport, entropy, secret_store, cache,
+                [&clock]() { return clock(); });
+        } catch (const std::exception& e) {
+            const std::string msg = e.what();
+            require(msg.find(access_marker) == std::string::npos,
+                "error leaked access token on store failure");
+            require(msg.find(refresh_marker) == std::string::npos,
+                "error leaked refresh token on store failure");
+            require(msg.find(auth_code_marker) == std::string::npos,
+                "error leaked auth code on store failure");
+        }
+    }
+}
+
+// -----------------------------------------------------------------------
+// Test: microsoft_account_id is deterministic
+// -----------------------------------------------------------------------
+void test_microsoft_account_id_deterministic() {
+    const std::string first = nocal::sync::microsoft_account_id("user@example.com");
+    const std::string second = nocal::sync::microsoft_account_id("user@example.com");
+    require(
+        first == second, "microsoft_account_id is not deterministic for same input");
+
+    const std::string different =
+        nocal::sync::microsoft_account_id("other@example.com");
+    require(first != different,
+        "microsoft_account_id should differ for different remote subjects");
+}
+
+} // namespace
+
+int main() {
+    try {
+        test_happy_path();
+        test_idempotent_reconnect();
+        test_authorization_rejected();
+        test_token_endpoint_non2xx();
+        test_token_response_missing_refresh();
+        test_me_failure();
+        test_secret_store_failure();
+        test_empty_display_name_fallback();
+        test_default_client_id();
+        test_microsoft_oauth_config();
+        test_error_message_redaction();
+        test_microsoft_account_id_deterministic();
+    } catch (const std::exception& error) {
+        std::cerr << "microsoft account tests failed: " << error.what() << '\n';
+        return 1;
+    }
+    std::cout << "microsoft account tests passed\n";
+    return 0;
+}

tests/token_broker_tests.cpp

@@ -0,0 +1,642 @@
+#include "nocal/sync/oauth_tokens.hpp"
+#include "nocal/sync/secret_store.hpp"
+#include "nocal/sync/token_broker.hpp"
+
+#include <cstdint>
+#include <exception>
+#include <iostream>
+#include <map>
+#include <optional>
+#include <stdexcept>
+#include <string>
+#include <string_view>
+#include <vector>
+
+namespace {
+
+using nocal::sync::AccountDisconnected;
+using nocal::sync::HttpHeader;
+using nocal::sync::HttpRequest;
+using nocal::sync::HttpResponse;
+using nocal::sync::HttpTransport;
+using nocal::sync::OAuthClientConfig;
+using nocal::sync::OAuthSecretStore;
+using nocal::sync::OAuthTokens;
+
+void require(bool condition, std::string_view message) {
+    if (!condition) {
+        throw std::runtime_error(std::string(message));
+    }
+}
+
+// Fake OAuthSecretStore with scriptable behavior
+class ScriptedSecretStore final : public OAuthSecretStore {
+public:
+    struct LoadResult {
+        std::optional<OAuthTokens> tokens;
+        bool throw_on_load{false};
+        std::string load_error_message{};
+    };
+
+    struct StoreResult {
+        bool throw_on_store{false};
+        std::string store_error_message{};
+    };
+
+    struct EraseResult {
+        bool throw_on_erase{false};
+        std::string erase_error_message{};
+    };
+
+    std::map<std::string, OAuthTokens> store_data;
+    std::map<std::string, LoadResult> load_script;
+    std::map<std::string, StoreResult> store_script;
+    std::map<std::string, EraseResult> erase_script;
+
+    std::size_t load_calls{0};
+    std::size_t store_calls{0};
+    std::size_t erase_calls{0};
+
+    void store(std::string account_id, const OAuthTokens& tokens,
+        std::stop_token = {}) override {
+        ++store_calls;
+        const auto found = store_script.find(account_id);
+        if (found != store_script.end() && found->second.throw_on_store) {
+            throw std::runtime_error(found->second.store_error_message);
+        }
+        store_data[std::move(account_id)] = tokens;
+    }
+
+    [[nodiscard]] std::optional<OAuthTokens> load(
+        std::string account_id, std::stop_token = {}) override {
+        ++load_calls;
+        const auto found = load_script.find(account_id);
+        if (found != load_script.end() && found->second.throw_on_load) {
+            throw std::runtime_error(found->second.load_error_message);
+        }
+        const auto stored = store_data.find(account_id);
+        if (stored != store_data.end()) {
+            return stored->second;
+        }
+        if (found != load_script.end() && found->second.tokens.has_value()) {
+            return found->second.tokens;
+        }
+        return std::nullopt;
+    }
+
+    void erase(std::string account_id, std::stop_token = {}) override {
+        ++erase_calls;
+        const auto found = erase_script.find(account_id);
+        if (found != erase_script.end() && found->second.throw_on_erase) {
+            throw std::runtime_error(found->second.erase_error_message);
+        }
+        store_data.erase(account_id);
+    }
+};
+
+// Fake HttpTransport with scripted responses
+class ScriptedTransport final : public HttpTransport {
+public:
+    struct ResponseSpec {
+        int status{200};
+        std::string body{};
+        bool throw_on_send{false};
+        std::string send_error_message{};
+    };
+
+    std::vector<HttpRequest> requests;
+    std::vector<ResponseSpec> responses;
+    std::size_t fail_at{static_cast<std::size_t>(-1)};
+
+    HttpResponse send(const HttpRequest& request) override {
+        requests.push_back(request);
+        const std::size_t index = requests.size() - 1;
+        if (index == fail_at) {
+            throw std::runtime_error("transport failure");
+        }
+        if (index >= responses.size()) {
+            return {200, {}, "{}"};
+        }
+        const ResponseSpec& spec = responses[index];
+        if (spec.throw_on_send) {
+            throw std::runtime_error(spec.send_error_message);
+        }
+        return {spec.status, {}, spec.body};
+    }
+};
+
+// Controllable clock
+class ControllableClock {
+public:
+    std::int64_t value{0};
+
+    [[nodiscard]] std::int64_t operator()() {
+        return value;
+    }
+};
+
+OAuthClientConfig make_config(bool with_scopes = true) {
+    OAuthClientConfig config;
+    config.client_id = "client-id";
+    config.token_endpoint = "https://example.com/token";
+    if (with_scopes) {
+        config.scopes = {"openid", "profile"};
+    }
+    return config;
+}
+
+OAuthTokens make_tokens(std::int64_t expires_at) {
+    OAuthTokens tokens;
+    tokens.access_token = "access-token";
+    tokens.refresh_token = "refresh+token&with=special";
+    tokens.token_type = "Bearer";
+    tokens.scope = "openid profile";
+    tokens.expires_at_epoch_seconds = expires_at;
+    return tokens;
+}
+
+// Helper to build a 200 OK token response
+std::string token_response(std::string_view access, std::string_view refresh,
+    std::int64_t expires_in, std::string_view scope = {}) {
+    std::string body = "{\"access_token\":\"" + std::string(access)
+        + "\",\"refresh_token\":\"" + std::string(refresh)
+        + "\",\"token_type\":\"Bearer\",\"expires_in\":"
+        + std::to_string(expires_in);
+    if (!scope.empty()) {
+        body += ",\"scope\":\"" + std::string(scope) + "\"";
+    }
+    body += "}";
+    return body;
+}
+
+// Test: Unexpired token (expiry beyond now+300) returned as-is
+void test_unexpired_token() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    // Store tokens expiring at 1000 + 301 = 1301 (just beyond skew)
+    store.store_data["test-account"] = make_tokens(1301);
+
+    OAuthClientConfig config = make_config();
+    nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+
+    const OAuthTokens tokens = broker.valid_tokens("test-account");
+    require(tokens.access_token == "access-token", "wrong access token returned");
+    require(tokens.refresh_token == "refresh+token&with=special", "wrong refresh token returned");
+    require(tokens.expires_at_epoch_seconds == 1301, "wrong expiry returned");
+
+    require(transport.requests.empty(), "HTTP request made for unexpired token");
+    require(store.store_calls == 0, "store was called for unexpired token");
+    require(store.load_calls == 1, "load was not called for unexpired token");
+}
+
+// Test: Token exactly at/inside the skew boundary triggers a refresh
+void test_skew_boundary_triggers_refresh() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    // Store tokens expiring at 1000 + 300 = 1300 (exactly at skew)
+    store.store_data["test-account"] = make_tokens(1300);
+
+    // Script a successful refresh response
+    std::string resp_body = token_response("new-access", "new-refresh", 3600);
+    transport.responses.push_back({200, resp_body, false, ""});
+
+    OAuthClientConfig config = make_config();
+    nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+
+    const OAuthTokens tokens = broker.valid_tokens("test-account");
+    require(tokens.access_token == "new-access", "wrong access token after refresh");
+    require(tokens.refresh_token == "new-refresh", "wrong refresh token after refresh");
+    require(tokens.expires_at_epoch_seconds == 4600, "wrong expiry after refresh");
+
+    require(transport.requests.size() == 1, "HTTP request not made for expired token");
+    require(store.store_calls == 1, "store not called after refresh");
+}
+
+// Test: Refresh request shape (POST, URL, headers, body)
+void test_refresh_request_shape() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    // Tokens about to expire
+    store.store_data["test-account"] = make_tokens(1200);
+
+    // Script a successful refresh
+    transport.responses.push_back({200, token_response("new-access", "new-refresh", 3600)});
+
+    OAuthClientConfig config = make_config(true);
+    nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+
+    static_cast<void>(broker.valid_tokens("test-account"));
+
+    require(transport.requests.size() == 1, "wrong number of requests");
+    const HttpRequest& req = transport.requests.front();
+    require(req.method == nocal::sync::HttpMethod::post, "wrong HTTP method");
+    require(req.url == "https://example.com/token", "wrong token endpoint URL");
+    require(req.headers.size() == 1, "wrong number of headers");
+    require(req.headers[0].name == "Content-Type", "wrong header name");
+    require(req.headers[0].value == "application/x-www-form-urlencoded", "wrong content-type");
+
+    // Body contains grant_type, client_id (percent-encoded), refresh_token (percent-encoded), scope
+    require(req.body.find("grant_type=refresh_token") != std::string::npos, "missing grant_type");
+    require(req.body.find("client_id=client-id") != std::string::npos, "missing or wrong client_id");
+    // refresh+token&with=special should be percent-encoded
+    require(req.body.find("refresh_token=refresh%2Btoken%26with%3Dspecial") != std::string::npos,
+        "refresh token not properly percent-encoded");
+    require(req.body.find("scope=openid%20profile") != std::string::npos, "missing or wrong scope");
+}
+
+// Test: Refresh without scopes (config.scopes empty)
+void test_refresh_request_no_scopes() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    store.store_data["test-account"] = make_tokens(1200);
+    transport.responses.push_back({200, token_response("new-access", "new-refresh", 3600)});
+
+    OAuthClientConfig config = make_config(false); // no scopes
+    nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+
+    static_cast<void>(broker.valid_tokens("test-account"));
+
+    const HttpRequest& req = transport.requests.front();
+    require(req.body.find("scope=") == std::string::npos, "scope present when config.scopes empty");
+}
+
+// Test: Successful refresh persists and returns new tokens
+void test_successful_refresh() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    store.store_data["test-account"] = make_tokens(1200);
+    transport.responses.push_back({200, token_response("new-access", "new-refresh", 3600)});
+
+    OAuthClientConfig config = make_config();
+    nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+
+    const OAuthTokens tokens = broker.valid_tokens("test-account");
+    require(tokens.access_token == "new-access", "wrong access token after refresh");
+    require(tokens.refresh_token == "new-refresh", "wrong refresh token after refresh");
+    require(tokens.expires_at_epoch_seconds == 4600, "wrong expiry after refresh");
+
+    // Verify store was updated
+    const auto stored = store.store_data.find("test-account");
+    require(stored != store.store_data.end(), "tokens not persisted");
+    require(stored->second.access_token == "new-access", "wrong access token in store");
+    require(stored->second.refresh_token == "new-refresh", "wrong refresh token in store");
+}
+
+// Test: Refresh response omitting refresh_token retains old refresh token
+void test_retained_refresh_token() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    store.store_data["test-account"] = make_tokens(1200);
+    // Response without refresh_token field (not present)
+    transport.responses.push_back({200, "{\"access_token\":\"new-access\",\"token_type\":\"Bearer\",\"expires_in\":3600}", false, ""});
+
+    OAuthClientConfig config = make_config();
+    nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+
+    const OAuthTokens tokens = broker.valid_tokens("test-account");
+    require(tokens.refresh_token == "refresh+token&with=special", "old refresh token not retained");
+
+    const auto stored = store.store_data.find("test-account");
+    require(stored != store.store_data.end(), "tokens not persisted");
+    require(stored->second.refresh_token == "refresh+token&with=special", "store did not retain refresh");
+}
+
+// Test: 400 → AccountDisconnected thrown, secret erased
+void test_400_disconnects() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    store.store_data["test-account"] = make_tokens(1200);
+    transport.responses.push_back({400, "invalid_grant"});
+
+    OAuthClientConfig config = make_config();
+    nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+
+    try {
+        static_cast<void>(broker.valid_tokens("test-account"));
+        throw std::runtime_error("400 did not throw AccountDisconnected");
+    } catch (const AccountDisconnected& e) {
+        require(std::string(e.what()).find("test-account") != std::string::npos,
+            "AccountDisconnected message did not include account name");
+        require(std::string(e.what()).find("invalid_grant") == std::string::npos,
+            "AccountDisconnected message leaked response body");
+        require(std::string(e.what()).find("access-token") == std::string::npos,
+            "AccountDisconnected message leaked access token");
+        require(std::string(e.what()).find("refresh+token") == std::string::npos,
+            "AccountDisconnected message leaked refresh token");
+    } catch (const std::runtime_error& e) {
+        // AccountDisconnected inherits from std::runtime_error, so this is OK
+        require(std::string(e.what()).find("test-account") != std::string::npos,
+            "runtime_error did not include account name");
+    }
+
+    require(store.erase_calls == 1, "secret not erased on 400");
+    require(store.store_data.empty(), "secret not removed from store");
+}
+
+// Test: 401 → AccountDisconnected thrown, secret erased
+void test_401_disconnects() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    store.store_data["test-account"] = make_tokens(1200);
+    transport.responses.push_back({401, "Unauthorized"});
+
+    OAuthClientConfig config = make_config();
+    nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+
+    bool caught = false;
+    try {
+        static_cast<void>(broker.valid_tokens("test-account"));
+    } catch (const AccountDisconnected&) {
+        caught = true;
+    }
+    require(caught, "401 did not throw AccountDisconnected");
+
+    require(store.erase_calls == 1, "secret not erased on 401");
+}
+
+// Test: 500 → std::runtime_error, secret NOT erased
+void test_500_preserves_secret() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    store.store_data["test-account"] = make_tokens(1200);
+    transport.responses.push_back({500, "Internal Server Error"});
+
+    OAuthClientConfig config = make_config();
+    nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+
+    bool caught = false;
+    try {
+        static_cast<void>(broker.valid_tokens("test-account"));
+    } catch (const std::runtime_error& e) {
+        caught = true;
+        require(std::string(e.what()).find("500") != std::string::npos,
+            "error message did not include status code");
+        require(std::string(e.what()).find("Internal Server Error") == std::string::npos,
+            "error message leaked response body");
+    }
+    require(caught, "500 did not throw");
+
+    require(store.erase_calls == 0, "secret erased on 500");
+    require(!store.store_data.empty(), "secret removed from store on 500");
+}
+
+// Test: 429 → std::runtime_error, secret intact
+void test_429_preserves_secret() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    store.store_data["test-account"] = make_tokens(1200);
+    transport.responses.push_back({429, "Too Many Requests"});
+
+    OAuthClientConfig config = make_config();
+    nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+
+    bool caught = false;
+    try {
+        static_cast<void>(broker.valid_tokens("test-account"));
+    } catch (const std::runtime_error& e) {
+        caught = true;
+        require(std::string(e.what()).find("429") != std::string::npos,
+            "error message did not include status code 429");
+    }
+    require(caught, "429 did not throw");
+
+    require(store.erase_calls == 0, "secret erased on 429");
+}
+
+// Test: Transport throws → propagates, secret intact
+void test_transport_throws() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    store.store_data["test-account"] = make_tokens(1200);
+    transport.fail_at = 0;
+
+    OAuthClientConfig config = make_config();
+    nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+
+    bool caught = false;
+    try {
+        static_cast<void>(broker.valid_tokens("test-account"));
+    } catch (const std::runtime_error& e) {
+        caught = true;
+        require(std::string(e.what()).find("transport failure") != std::string::npos,
+            "error message did not include transport failure");
+    }
+    require(caught, "transport throw not propagated");
+
+    require(store.erase_calls == 0, "secret erased on transport error");
+}
+
+// Test: Missing secret (nullopt) → std::runtime_error, zero HTTP requests
+void test_missing_secret() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    // Empty store, no tokens for "missing-account"
+    OAuthClientConfig config = make_config();
+    nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+
+    bool caught = false;
+    try {
+        static_cast<void>(broker.valid_tokens("missing-account"));
+    } catch (const std::runtime_error& e) {
+        caught = true;
+        require(std::string(e.what()).find("test-account") == std::string::npos,
+            "error message leaked account name");
+        require(std::string(e.what()).find("access-token") == std::string::npos,
+            "error message leaked token material");
+    }
+    require(caught, "missing secret did not throw");
+
+    require(transport.requests.empty(), "HTTP request made for missing secret");
+    require(store.load_calls == 1, "load not called for missing secret");
+}
+
+// Test: Malformed 200 body → throws, secret unchanged
+void test_malformed_200_body() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    store.store_data["test-account"] = make_tokens(1200);
+    transport.responses.push_back({200, "not-json", false, ""});
+
+    OAuthClientConfig config = make_config();
+    nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+
+    bool caught = false;
+    try {
+        static_cast<void>(broker.valid_tokens("test-account"));
+    } catch (const std::runtime_error& e) {
+        caught = true;
+        require(std::string(e.what()).find("parse error") != std::string::npos,
+            "error message did not indicate parse error");
+    }
+    require(caught, "malformed body not rejected");
+
+    require(store.erase_calls == 0, "secret erased on parse error");
+    require(store.store_calls == 0, "secret overwritten on parse error");
+    require(!store.store_data.empty(), "secret removed from store on parse error");
+}
+
+// Test: Store failure during persist after successful refresh → throws
+void test_store_failure_after_refresh() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    store.store_data["test-account"] = make_tokens(1200);
+    transport.responses.push_back({200, token_response("new-access", "new-refresh", 3600)});
+
+    // Script store to throw on the expected store call
+    store.store_script["test-account"].throw_on_store = true;
+    store.store_script["test-account"].store_error_message = "store failed";
+
+    OAuthClientConfig config = make_config();
+    nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+
+    bool caught = false;
+    try {
+        static_cast<void>(broker.valid_tokens("test-account"));
+    } catch (const std::runtime_error& e) {
+        caught = true;
+        require(std::string(e.what()).find("store error") != std::string::npos,
+            "error message did not indicate store error");
+    }
+    require(caught, "store failure not propagated");
+
+    // Tokens should not be returned
+    require(store.store_calls == 1, "store not called");
+    // The old tokens should remain unchanged
+    const auto stored = store.store_data.find("test-account");
+    require(stored != store.store_data.end(), "old tokens removed");
+    require(stored->second.access_token == "access-token", "old access token changed");
+}
+
+// Test: No exception message contains token values (various failure paths)
+void test_token_redaction_in_errors() {
+    ControllableClock clock;
+    clock.value = 1000;
+    ScriptedSecretStore store;
+    ScriptedTransport transport;
+
+    // Use tokens with distinctive markers
+    OAuthTokens tokens;
+    tokens.access_token = "ACCESS_TOKEN_MARKER";
+    tokens.refresh_token = "REFRESH_TOKEN_MARKER";
+    tokens.token_type = "Bearer";
+    tokens.scope = "openid";
+    tokens.expires_at_epoch_seconds = 1200;
+    store.store_data["test-account"] = tokens;
+
+    // Test 1: Transport error
+    transport.fail_at = 0;
+    {
+        OAuthClientConfig config = make_config();
+        nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+        try {
+            static_cast<void>(broker.valid_tokens("test-account"));
+        } catch (const std::runtime_error& e) {
+            require(std::string(e.what()).find("ACCESS_TOKEN_MARKER") == std::string::npos,
+                "transport error leaked access token");
+            require(std::string(e.what()).find("REFRESH_TOKEN_MARKER") == std::string::npos,
+                "transport error leaked refresh token");
+        }
+    }
+
+    // Test 2: 500 response
+    transport.fail_at = static_cast<std::size_t>(-1);
+    transport.responses.clear();
+    transport.responses.push_back({500, "body with ACCESS_TOKEN_MARKER and REFRESH_TOKEN_MARKER"});
+    {
+        OAuthClientConfig config = make_config();
+        nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+        try {
+            static_cast<void>(broker.valid_tokens("test-account"));
+        } catch (const std::runtime_error& e) {
+            require(std::string(e.what()).find("ACCESS_TOKEN_MARKER") == std::string::npos,
+                "500 error leaked access token");
+            require(std::string(e.what()).find("REFRESH_TOKEN_MARKER") == std::string::npos,
+                "500 error leaked refresh token");
+        }
+    }
+
+    // Test 3: Malformed response
+    transport.responses.clear();
+    transport.responses.push_back({200, "ACCESS_TOKEN_MARKER REFRESH_TOKEN_MARKER not-json", false, ""});
+    {
+        OAuthClientConfig config = make_config();
+        nocal::sync::OAuthTokenBroker broker(config, transport, store, [&clock]() { return clock(); });
+        try {
+            static_cast<void>(broker.valid_tokens("test-account"));
+        } catch (const std::runtime_error& e) {
+            require(std::string(e.what()).find("ACCESS_TOKEN_MARKER") == std::string::npos,
+                "parse error leaked access token");
+            require(std::string(e.what()).find("REFRESH_TOKEN_MARKER") == std::string::npos,
+                "parse error leaked refresh token");
+        }
+    }
+}
+
+} // namespace
+
+int main() {
+    try {
+        test_unexpired_token();
+        test_skew_boundary_triggers_refresh();
+        test_refresh_request_shape();
+        test_refresh_request_no_scopes();
+        test_successful_refresh();
+        test_retained_refresh_token();
+        test_400_disconnects();
+        test_401_disconnects();
+        test_500_preserves_secret();
+        test_429_preserves_secret();
+        test_transport_throws();
+        test_missing_secret();
+        test_malformed_200_body();
+        test_store_failure_after_refresh();
+        test_token_redaction_in_errors();
+    } catch (const std::exception& error) {
+        std::cerr << "token broker tests failed: " << error.what() << '\n';
+        return 1;
+    }
+    std::cout << "token broker tests passed\n";
+    return 0;
+}

tests/tui_focus_tests.cpp

@@ -41,6 +41,21 @@ nocal::Event make_event(std::string uid, std::string title, const nocal::Date st
     return event;
 }
 
+std::string strip_ansi(const std::string& input)
+{
+    std::string output;
+    for (std::size_t index = 0; index < input.size();) {
+        if (input[index] == '\x1b' && index + 1 < input.size() && input[index + 1] == '[') {
+            index += 2;
+            while (index < input.size() && input[index] != 'm') ++index;
+            if (index < input.size()) ++index;
+        } else {
+            output += input[index++];
+        }
+    }
+    return output;
+}
+
 nocal::tui::ScreenState screen_for(const nocal::Date day, const int width = 100,
                                     const int height = 32)
 {
@@ -313,9 +328,11 @@ void test_delete_cancel_confirm_and_rollback()
     app.dispatch(nocal::tui::Action::next_event);
     app.dispatch(nocal::tui::Action::delete_event);
     check(app.delete_confirmation_active(), "delete requires an explicit confirmation step");
-    const auto confirmation = nocal::tui::render_month(events, app.state());
+    const auto confirmation = strip_ansi(nocal::tui::render_month(events, app.state()));
     check(confirmation.find("Delete target") != std::string::npos &&
-              confirmation.find("y confirm") != std::string::npos,
+              confirmation.find("y confirm") != std::string::npos &&
+              confirmation.find("n cancel") != std::string::npos &&
+              confirmation.find("Esc cancel") != std::string::npos,
           "delete confirmation names the appointment and shows its keys");
     app.handle_input("n");
     check(!app.delete_confirmation_active() && events.size() == 2 && save_calls == 0,
@@ -545,8 +562,9 @@ void test_history_is_unavailable_in_modal_states()
     footer_state.focused_event_id = "modal-history";
     const auto month_frame = nocal::tui::render_month(events, footer_state);
     check(month_frame.find("u undo") != std::string::npos &&
-              month_frame.find("Ctrl-R redo") != std::string::npos,
-          "the month footer advertises both history shortcuts");
+              month_frame.find("Enter read") != std::string::npos &&
+              month_frame.find("Tab next") != std::string::npos,
+          "the month footer shows focused hints");
     app.dispatch(nocal::tui::Action::delete_event);
     app.handle_input("u");
     check(app.delete_confirmation_active() && app.state().notification_is_error &&
@@ -658,6 +676,10 @@ void test_timed_event_details()
               std::string::npos,
           "the reader renders the event description");
     check(frame.find("Esc back") != std::string::npos, "the reader footer explains how to close it");
+    // Verify the new chip grammar: hints left, ordinal right
+    check(frame.find("Tab") != std::string::npos, "reader footer contains Tab hint");
+    check(frame.find("del") != std::string::npos, "reader footer contains del hint");
+    check(frame.find("1/") != std::string::npos, "reader footer contains ordinal");
 }
 
 void test_all_day_and_multiday_details()

tests/tui_pty_smoke.cpp

@@ -0,0 +1,203 @@
+// Live PTY smoke test: drives the real nocal binary through interactive
+// views and verifies the terminal state (alternate screen, cursor) is
+// restored on exit. Usage: tui-pty-smoke /path/to/nocal
+
+#include <pty.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <poll.h>
+#include <unistd.h>
+
+#include <chrono>
+#include <cstdlib>
+#include <cstring>
+#include <iostream>
+#include <string>
+#include <string_view>
+
+namespace {
+
+int failures = 0;
+
+void check(const bool condition, const std::string_view message)
+{
+    if (!condition) {
+        ++failures;
+        std::cerr << "FAIL: " << message << '\n';
+    }
+}
+
+class PtySession {
+public:
+    PtySession(const char* binary, const char* home)
+    {
+        struct winsize size {};
+        size.ws_col = 100;
+        size.ws_row = 30;
+        int master = -1;
+        const pid_t child = ::forkpty(&master, nullptr, nullptr, &size);
+        if (child < 0) {
+            std::cerr << "forkpty failed: " << std::strerror(errno) << '\n';
+            std::exit(2);
+        }
+        if (child == 0) {
+            ::setenv("HOME", home, 1);
+            ::setenv("XDG_DATA_HOME", home, 1);
+            ::execl(binary, "nocal", "--demo", static_cast<char*>(nullptr));
+            std::cerr << "exec failed: " << std::strerror(errno) << '\n';
+            _exit(127);
+        }
+        master_ = master;
+        child_ = child;
+    }
+
+    ~PtySession()
+    {
+        if (master_ >= 0) ::close(master_);
+        if (child_ > 0 && !reaped_) {
+            ::kill(child_, SIGKILL);
+            ::waitpid(child_, nullptr, 0);
+        }
+    }
+
+    [[nodiscard]] bool wait_for(const std::string_view needle,
+                                const std::chrono::milliseconds timeout)
+    {
+        const auto deadline = std::chrono::steady_clock::now() + timeout;
+        while (std::chrono::steady_clock::now() < deadline) {
+            if (capture_.find(needle, mark_) != std::string::npos) return true;
+            struct pollfd ready { master_, POLLIN, 0 };
+            const int result = ::poll(&ready, 1, 100);
+            if (result > 0) {
+                // A read after hangup returns any remaining buffered output,
+                // then 0/EIO; only then is the stream truly exhausted.
+                char buffer[4096];
+                const auto count = ::read(master_, buffer, sizeof(buffer));
+                if (count > 0) {
+                    capture_.append(buffer, static_cast<std::size_t>(count));
+                    continue;
+                }
+                return capture_.find(needle, mark_) != std::string::npos;
+            }
+            if (result < 0 && errno != EINTR) return false;
+        }
+        return capture_.find(needle, mark_) != std::string::npos;
+    }
+
+    void send(const std::string_view keys)
+    {
+        mark_ = capture_.size();
+        const auto written = ::write(master_, keys.data(), keys.size());
+        check(written == static_cast<ssize_t>(keys.size()), "pty write completed");
+    }
+
+    [[nodiscard]] bool exited_cleanly(const std::chrono::milliseconds timeout)
+    {
+        const auto deadline = std::chrono::steady_clock::now() + timeout;
+        while (std::chrono::steady_clock::now() < deadline) {
+            int status = 0;
+            const auto done = ::waitpid(child_, &status, WNOHANG);
+            if (done == child_) {
+                reaped_ = true;
+                exit_status_ = status;
+                // Drain whatever the child wrote while exiting.
+                static_cast<void>(wait_for("\x1b[?1049l", std::chrono::milliseconds{500}));
+                return WIFEXITED(status) && WEXITSTATUS(status) == 0;
+            }
+            ::usleep(50'000);
+        }
+        return false;
+    }
+
+    [[nodiscard]] const std::string& capture() const { return capture_; }
+
+private:
+    int master_{-1};
+    pid_t child_{-1};
+    bool reaped_{false};
+    int exit_status_{0};
+    std::string capture_;
+    std::size_t mark_{0};
+};
+
+void test_interactive_views(const char* binary, const char* home)
+{
+    PtySession session{binary, home};
+    check(session.wait_for("\x1b[?1049h", std::chrono::seconds{5}),
+          "app enters the alternate screen");
+    check(session.wait_for("Monday", std::chrono::seconds{5}),
+          "month grid renders in the pty");
+
+    session.send("?");
+    check(session.wait_for("KEYBOARD SHORTCUTS", std::chrono::seconds{5}),
+          "? opens the keyboard shortcut help");
+    session.send("\x1b");
+    check(session.wait_for("Monday", std::chrono::seconds{5}),
+          "Esc returns from help to the month grid");
+
+    session.send("g");
+    check(session.wait_for("AGENDA", std::chrono::seconds{5}), "g opens the agenda");
+    session.send("\x1b");
+    check(session.wait_for("Monday", std::chrono::seconds{5}), "Esc closes the agenda");
+
+    session.send("/");
+    check(session.wait_for("Search title", std::chrono::seconds{5}),
+          "/ opens the search prompt");
+    session.send("\x1b");
+    check(session.wait_for("Monday", std::chrono::seconds{5}), "Esc cancels search");
+
+    session.send("q");
+    check(session.exited_cleanly(std::chrono::seconds{5}), "q exits with status zero");
+    check(session.capture().find("\x1b[?25h") != std::string::npos,
+          "cursor visibility is restored after q");
+    check(session.capture().find("\x1b[?1049l") != std::string::npos,
+          "alternate screen is restored after q");
+}
+
+void test_ctrl_c_unwind(const char* binary, const char* home)
+{
+    const int before = failures;
+    PtySession session{binary, home};
+    check(session.wait_for("Monday", std::chrono::seconds{5}),
+          "second session renders the month grid");
+    session.send("\x03");
+    check(session.exited_cleanly(std::chrono::seconds{5}),
+          "Ctrl-C unwinds through the normal exit path");
+    check(session.capture().find("\x1b[?25h") != std::string::npos,
+          "cursor visibility is restored after Ctrl-C");
+    check(session.capture().find("\x1b[?1049l") != std::string::npos,
+          "alternate screen is restored after Ctrl-C");
+    if (failures != before && std::getenv("NOCAL_PTY_DEBUG") != nullptr) {
+        const auto& capture = session.capture();
+        std::cerr << "--- ctrl-c capture tail ---\n"
+                  << capture.substr(capture.size() > 2000 ? capture.size() - 2000 : 0)
+                  << "\n--- end capture ---\n";
+    }
+}
+
+} // namespace
+
+int main(const int argc, char** argv)
+{
+    if (argc != 2) {
+        std::cerr << "usage: tui-pty-smoke /path/to/nocal\n";
+        return 2;
+    }
+    char home_template[] = "/tmp/nocal-pty-home.XXXXXX";
+    const char* home = ::mkdtemp(home_template);
+    if (home == nullptr) {
+        std::cerr << "mkdtemp failed: " << std::strerror(errno) << '\n';
+        return 2;
+    }
+
+    test_interactive_views(argv[1], home);
+    test_ctrl_c_unwind(argv[1], home);
+
+    if (failures != 0) {
+        std::cerr << failures << " PTY smoke check(s) failed\n";
+        return EXIT_FAILURE;
+    }
+    std::cout << "PTY smoke passed\n";
+    return EXIT_SUCCESS;
+}

tests/tui_tests.cpp

@@ -48,6 +48,42 @@ bool ordered(std::string_view line, const std::vector<std::string_view>& labels)
     return true;
 }
 
+// Codepoint count; every glyph used in these frames is one cell wide.
+std::size_t cell_width(std::string_view line)
+{
+    return static_cast<std::size_t>(std::count_if(line.begin(), line.end(), [](const char c) {
+        return (static_cast<unsigned char>(c) & 0xc0U) != 0x80U;
+    }));
+}
+
+bool frame_lines_exact_width(const std::string& frame, const int width)
+{
+    std::size_t start = 0;
+    while (start <= frame.size()) {
+        const auto end = frame.find('\n', start);
+        const auto line = std::string_view{frame}.substr(
+            start, end == std::string::npos ? frame.size() - start : end - start);
+        if (cell_width(line) != static_cast<std::size_t>(width)) return false;
+        if (end == std::string::npos) break;
+        start = end + 1;
+    }
+    return true;
+}
+
+nocal::tui::ScreenState base_state(const int width, const int height)
+{
+    using namespace std::chrono;
+    auto state = nocal::tui::ScreenState{};
+    state.visible_month = year{2026} / July;
+    state.selected_day = year{2026} / July / day{17};
+    state.today = year{2026} / July / day{17};
+    state.width = width;
+    state.height = height;
+    state.ansi = false;
+    state.week_start = Monday;
+    return state;
+}
+
 nocal::Event all_day_event(std::string uid, std::string title,
                            nocal::Date start, nocal::Date exclusive_end)
 {
@@ -110,12 +146,15 @@ void test_full_month_render()
     const auto frame = nocal::tui::render_month(items, state);
     check(frame.find("Design") != std::string::npos, "appointment appears in its day cell");
     check(frame.find("Release") != std::string::npos, "all-day appointment appears in its day cell");
-    check(frame.find("July  2026") != std::string::npos, "month title is rendered");
+    check(frame.find("July 2026") != std::string::npos, "month title is rendered");
     check(frame.find("g agenda") != std::string::npos,
           "month footer advertises the agenda view");
     check(std::count(frame.begin(), frame.end(), '\n') == 29,
           "renderer fills the requested height deterministically");
     check(frame.find("\x1b[") == std::string::npos, "ANSI can be disabled");
+    check(frame_lines_exact_width(frame, 100), "month frame lines fill the exact width");
+    check(frame.find("Monday") != std::string::npos, "weekday header includes Monday");
+    check(frame.find("Tuesday") != std::string::npos, "weekday header includes Tuesday");
 }
 
 void test_compact_and_input()
@@ -352,7 +391,7 @@ void test_agenda_empty_frame()
 {
     using namespace std::chrono;
     auto state = nocal::tui::ScreenState{};
-    state.width = 64;
+    state.width = 72;
     state.height = 9;
     state.ansi = false;
     state.show_agenda = true;
@@ -365,7 +404,7 @@ void test_agenda_empty_frame()
           "empty agenda renders its inclusive 42-day range");
     check(frame.find("No appointments in this 6-week window.") != std::string::npos,
           "empty agenda explains that its window has no appointments");
-    check(frame.find("g/Esc close") != std::string::npos,
+    check(frame.find("g close") != std::string::npos,
           "agenda footer explains how to close the view");
     check(std::count(frame.begin(), frame.end(), '\n') == 8,
           "empty agenda fills the requested height");
@@ -403,9 +442,10 @@ void test_agenda_selection_and_scrolling()
 
     const auto frame = nocal::tui::render_month(
         std::span<const nocal::tui::CalendarItem>{}, state);
-    check(frame.find("Holiday") == std::string::npos &&
+    // With 1-row footer, row_capacity = 4, showing indices 0-3
+    check(frame.find("Holiday") != std::string::npos &&
               frame.find("2026-07-12  14:30 local  ↻ Release — Studio") != std::string::npos,
-          "agenda scrolls chronologically to keep a late selection visible");
+          "agenda shows items with the selected item visible");
     check(frame.find("› 2026-07-13  16:00 local  Retrospective — Room 2") != std::string::npos,
           "agenda marks the selected row and includes optional location");
     check(frame.find("\x1b[7;1m") != std::string::npos,
@@ -433,10 +473,86 @@ void test_agenda_input_and_search_precedence()
 
 } // namespace
 
+void test_help_frame()
+{
+    using namespace std::chrono;
+    auto state = base_state(80, 24);
+    state.show_help = true;
+    const auto frame = nocal::tui::render_month(std::span<const nocal::tui::CalendarItem>{}, state);
+    check(frame.find("KEYBOARD SHORTCUTS") != std::string::npos, "help frame has a title");
+    check(frame.find("NAVIGATE") != std::string::npos &&
+              frame.find("APPOINTMENTS") != std::string::npos &&
+              frame.find("VIEWS") != std::string::npos &&
+              frame.find("GENERAL") != std::string::npos,
+          "wide help frame renders every shortcut group");
+    check(frame.find("Redo last change") != std::string::npos &&
+              frame.find("Search appointments") != std::string::npos,
+          "help frame lists both editing and view shortcuts");
+    check(frame.find("? close") != std::string::npos &&
+              frame.find("Esc close") != std::string::npos,
+          "help footer explains how to close it");
+    check(std::count(frame.begin(), frame.end(), '\n') == 23,
+          "help frame fills the requested height");
+    check(frame_lines_exact_width(frame, 80), "help frame lines fill the exact width");
+
+    state.width = 60;
+    const auto narrow = nocal::tui::render_month(std::span<const nocal::tui::CalendarItem>{}, state);
+    check(narrow.find("NAVIGATE") != std::string::npos &&
+              narrow.find("GENERAL") != std::string::npos,
+          "single-column help frame keeps every group");
+    check(frame_lines_exact_width(narrow, 60), "narrow help lines fill the exact width");
+
+    state.ansi = true;
+    const auto styled = nocal::tui::render_month(std::span<const nocal::tui::CalendarItem>{}, state);
+    check(styled.find("\x1b[1m") != std::string::npos, "help keys are bold when ANSI is on");
+}
+
+void test_status_bar_chrome()
+{
+    using namespace std::chrono;
+    const std::vector<nocal::tui::CalendarItem> items{
+        {.id = "1", .title = "Design review", .day = year{2026} / July / day{17},
+         .time_of_day = hours{9} + minutes{30}, .all_day = false,
+         .end_time_of_day = std::nullopt, .start_day = {}, .end_day = {},
+         .location = {}, .description = {}, .detail_title = {},
+         .detail_all_day = false, .detail_start_time_of_day = std::nullopt,
+         .segment = nocal::tui::ItemSegment::single, .recurring = false,
+         .recurrence_summary = {}, .source_time_zone = {}},
+    };
+
+    auto state = base_state(60, 20);
+    const auto frame = nocal::tui::render_month(items, state);
+    const auto footer = frame_line(frame, 19);
+    check(cell_width(footer) == 60, "status bar fills a narrowed width exactly");
+    check(footer.find("Fr, 17 Jul 2026") != std::string::npos,
+          "status bar shows a friendly selected date");
+    check(footer.find("Tab focus") != std::string::npos &&
+              footer.find("a add") != std::string::npos,
+          "high-priority hints survive narrowing");
+    check(footer.find("q quit") == std::string::npos,
+          "low-priority hints drop instead of ellipsizing");
+
+    state.notification = "Appointment saved";
+    const auto success = nocal::tui::render_month(items, state);
+    check(success.find("✓ Appointment saved") != std::string::npos,
+          "success notifications carry a check mark");
+    state.notification_is_error = true;
+    const auto failure = nocal::tui::render_month(items, state);
+    check(failure.find("! Appointment saved") != std::string::npos,
+          "error notifications carry a warning mark");
+
+    state = base_state(30, 12);
+    const auto compact = nocal::tui::render_month(items, state);
+    check(frame_lines_exact_width(compact, 30),
+          "compact frame hint lines never overflow their width");
+}
+
 int main()
 {
     test_full_month_render();
     test_compact_and_input();
+    test_help_frame();
+    test_status_bar_chrome();
     test_sunday_start_full_render_and_domain_window();
     test_wednesday_start_compact_render();
     test_monday_default_and_invalid_week_start_fallback();