## Why
The app server previously rejected OAuth login for enterprise-managed MCP servers. These servers need an explicit sign-in flow that ties saved authorization to the active Codex user and workspace and prevents canceled or superseded attempts from saving credentials.
## What changed
- Enable enterprise sign-in through `mcpServer/oauth/login` for configured servers with a connected thread, trusted IdP registration, and `features.use_xaa` enabled. Scope shared enterprise credentials by user, workspace, issuer, and client ID.
- Add `loginId` to MCP OAuth login responses and completion notifications, preserving compatibility with older servers that omit it.
- Support enterprise login replacement and `account/login/cancel`, wait for callback listener shutdown before replacement, and recheck account and configuration before saving grants. Fence stale attempts across processes and account changes.
- Remove shared enterprise authorization during account logout and `codex mcp logout`, including when the feature is disabled. Continue account logout if enterprise cleanup fails, and invalidate MCP runtimes on account changes.
Start a fresh session after successful enterprise sign-in to use the saved grant.
## Testing
Add regression coverage for login replacement and cancellation, callback port reuse, account changes during setup, cross-process logout invalidation, persisted workspace policy selection, cleanup failures, and responses from older servers without `loginId`.
GitOrigin-RevId: 7ed4caaab4659ed1e67064262cf5cee48e3a26ac
## Why
MCP OAuth configuration supported a pre-registered client ID but could not supply a client secret for token exchange or refresh.
## What changed
- Add `oauth.client_secret` and `codex mcp add --oauth-client-secret`, requiring a nonempty secret and client ID. Persist the secret in server configuration and accept `clientSecret` in plugin configuration.
- Pass configured credentials through CLI, app-server, and plugin login flows and token refresh. Require a new login when a configured confidential client's ID differs from stored credentials.
- Redact secrets in debug output and keep them out of authorization URLs and persisted OAuth token records.
- Invalidate cached OAuth connections when the configured client ID or secret changes.
## Testing
Add coverage for configuration validation and round trips, CLI argument redaction and subsequent login, app-server login, connection invalidation, and refresh with `client_secret_basic` and `client_secret_post` in both refresh modes. Verify secret exclusion from token records and reject mismatched client IDs before contacting the provider.
GitOrigin-RevId: 85bb0e410e9e68e6cd68eb6359badfc7eac78147
## Why
A `503` from an issuer's OAuth metadata endpoint can block discovery even when its OIDC metadata is available, preventing expired OAuth tokens from being refreshed during MCP startup.
## What changed
Try the same issuer's OIDC discovery endpoints when an OAuth authorization-server metadata GET returns `503`. Support issuers with path components and keep all attempts within the original request's timeout.
Reuse existing header, origin, and response-size checks, leave issuer validation to RMCP, and do not follow fallback redirects. Preserve discovery errors when fallback fails instead of enabling legacy endpoint fallback, and propagate terminal HTTP failures.
## Testing
Add tests for OIDC candidate order, malformed metadata, issuer mismatches, header isolation, redirects, terminal failures, unaffected requests, and the shared timeout. Add startup coverage for refreshing expired persisted tokens after OIDC fallback in both legacy and coordinated refresh modes.
GitOrigin-RevId: 6d94fd09e9ba26cb83e029171449e91410a0f6cb
## Why
Headers configured for an MCP resource can contain credentials and must not be
forwarded to a different origin during OAuth discovery, registration, or token
exchange.
## What changed
- Apply configured resource headers only to OAuth requests on the MCP resource
origin, while allowing OAuth-generated headers to take precedence.
- Follow credentialed OAuth redirects only when each destination remains on the
resource origin. Preserve redirect method semantics, the overall timeout, the
response size limit, and a maximum of 10 redirects.
- Use the Codex MCP user agent for requests to authorization-server origins.
## Testing
Add coverage for cross-origin header isolation, same-origin dynamic client
registration redirects, OAuth header precedence, token refresh, timeout
accounting, and response size limits.
GitOrigin-RevId: 609d06e2b065e4aa9ca5382b4ae60455f9e26db9
Nick Steele