- `src/core/oauth-provider.ts` (v0.26.0) — `GBrainOAuthProvider` implementing the MCP SDK's `OAuthServerProvider` + `OAuthRegisteredClientsStore` interfaces. Backed by raw SQL (works on both PGLite and Postgres — OAuth is infrastructure, not a BrainEngine concern). Full OAuth 2.1 spec: `authorize` + `exchangeAuthorizationCode` with PKCE (for ChatGPT), `client_credentials` (for Perplexity / Claude), `refresh_token` with rotation, `revokeToken`, `registerClient` (DCR path validates redirect_uri must be `https://` or loopback per RFC 6749 §3.1.2.1). All tokens + client secrets SHA-256 hashed before storage. Auth codes single-use with 10-minute TTL via atomic `DELETE...RETURNING` (closes RFC 6749 §10.5 TOCTOU race). Refresh rotation also `DELETE...RETURNING` (closes §10.4 stolen-token detection bypass). `pgArray()` escapes commas/quotes/braces in elements so a comma-bearing redirect_uri can't smuggle a second array element. Legacy `access_tokens` fallback in `verifyAccessToken` grandfathers pre-v0.26 bearer tokens as `read+write+admin`. `sweepExpiredTokens()` runs on startup wrapped in try/catch. **v0.26.2:** module-private `coerceTimestamp()` boundary helper at the top of the file normalizes postgres-driver-as-string BIGINT columns to JS numbers at every read site (5 call sites: `getClient` L112+L113 for DCR `/register` RFC 7591 §3.2.1 numeric timestamps, `exchangeRefreshToken` L274 + `verifyAccessToken` L296+L303 for the SDK's `typeof === 'number'` bearerAuth check). Throws on non-finite input (NaN/Infinity) so corrupt rows fail loud at the boundary instead of riding through as `expiresAt: NaN`; returns undefined for SQL NULL so callers decide NULL semantics explicitly (refresh + access token paths treat NULL as expired). Helper intentionally NOT promoted to `src/core/utils.ts` — codex review flagged repo-wide BIGINT precision-loss risk for a generic helper.

- `src/commands/auth.ts` — Token management. `gbrain auth create/list/revoke/test` for legacy bearer tokens (v0.22.7 wired as a first-class CLI subcommand) plus `gbrain auth register-client` (v0.26.0) and `gbrain auth revoke-client <client_id>` (v0.26.2) for OAuth 2.1 client lifecycle. `revoke-client` runs an atomic `DELETE...RETURNING` on `oauth_clients`; FK `ON DELETE CASCADE` on `oauth_tokens.client_id` and `oauth_codes.client_id` purges every active token + authorization code in a single transaction. `process.exit(1)` on no-such-client (idempotent — re-running on the same id produces the same exit-1 message). Legacy tokens stored as SHA-256 hashes in `access_tokens`; OAuth clients in `oauth_clients`. As of v0.26.0, legacy tokens grandfather to `read+write+admin` scopes on the OAuth HTTP server, so pre-v0.26 deployments keep working with no migration.

`test/oauth.test.ts` (v0.26.0 OAuth 2.1 provider — 27 cases: register, getClient, `client_credentials` grant exchange, `authorization_code` flow with PKCE challenge / verifier, refresh token rotation, `verifyAccessToken` with both OAuth + legacy `access_tokens` fallback, `revokeToken`, `sweepExpiredTokens`, and a contract test asserting `scope` + `localOnly` annotations are set correctly on all 30 operations; **v0.26.2** adds 5 `coerceTimestamp` unit cases (null/undefined/string/number/throw-on-NaN), NULL-`expires_at`-as-expired contract tests for both refresh + access token paths, and a cascade-delete contract test asserting `revoke-client` purges `oauth_tokens` + `oauth_codes` rows via FK CASCADE),

- `test/e2e/serve-http-oauth.test.ts` (v0.26.0, expanded v0.26.2) — real-Postgres E2E against `gbrain serve --http` with full OAuth 2.1. Spawns a subprocess server, registers a client via the CLI, mints `client_credentials` tokens, exercises the `/mcp` JSON-RPC pipeline. **v0.26.2 adds:** real DCR `/register` HTTP-level response-shape test (asserts `typeof body.client_id_issued_at === 'number'` over the wire — RFC 7591 §3.2.1 spec compliance, not just internal-store shape); real CLI subprocess test for `revoke-client` (registers → mints token → revokes via `execSync` → asserts token rejected at `/mcp` → asserts re-run exits 1); server fixture flips on `--enable-dcr` so `/register` is reachable. **bun execSync env-inheritance fix:** bun's `execSync` does NOT inherit env mutations done via `process.env.X = ...`, only OS-level env from before bun started. helpers.ts loads `.env.testing` and sets `DATABASE_URL` via `process.env` mutation, which is invisible to subprocesses unless `env: { ...process.env }` is passed explicitly — every subprocess call in this file passes `env: { ...process.env }` for that reason. Reference fix for the next maintainer hitting the same failure mode in sibling sync/cycle/dream/claw-test E2Es. `afterAll` cleanup is guarded on `clientId` (won't throw if `beforeAll` failed before registration); cleanup errors surface to stderr without throwing so real test failures aren't masked. Tracks DCR-registered clients alongside the manual one. Skips gracefully when `DATABASE_URL` is unset.