## Why
Synchronous auth header construction could silently return no credentials when managed authentication became unavailable. Callers need an error to avoid sending requests with missing or partial authentication.
## What changed
- Make `AuthProvider::add_auth_headers`, `to_auth_headers`, and auth header telemetry fallible, and propagate failures through request and WebSocket setup.
- Return a transient error when managed authentication is unavailable, and preserve network policy denials through auth error conversion.
- Retry transient MCP authentication errors while treating build errors and policy denials as terminal.
- Cancel local MCP event streams before resolving authentication so cleanup still works when credentials become unavailable.
## Testing
Add regression coverage for rejected partial authentication, async header resolution, terminal auth errors without sending requests, managed account changes, MCP retry classification, and local stream cancellation after authentication becomes unavailable.
GitOrigin-RevId: 39d981e232cba1e302de502a2fa6239101114ed1
## Why
Form and URL elicitations could keep waiting for a response and leave tool timeouts paused after cancellation. Remembered cancellations could also affect reused request IDs on a new connection.
## What changed
- Honor request cancellation and server cancellation notifications for all elicitations, without requiring user-verification support. Return `cancel` and release pending response routes and timeout pauses.
- Create a fresh elicitation service for each connection attempt, including initialization retries and session recovery, so cancellation state stays scoped to its connection.
## Testing
Add regression tests for form and URL elicitation cancellation, cleanup on service shutdown, and acceptance of previously cancelled request IDs after connection recovery.
GitOrigin-RevId: 388a8d72e55e89ad3d44d4739d8434485588aa1a
## What changed
- Honor `McpOAuthRefreshMode::Coordinated` for streamable HTTP MCP connections by letting RMCP refresh and persist credentials through the pinned credential store.
- Reread credentials while holding the refresh lock, persist refreshed tokens before retrying requests, and serialize login and logout writes with in-flight refreshes.
- Keep OAuth preparation outside MCP operation and handshake deadlines, and allow refresh persistence to finish if the initiating caller is cancelled.
## Testing
- Cover coordinated startup refresh, concurrent refreshes, `401` retries, credential mutation races, provider timeouts, and caller cancellation.
GitOrigin-RevId: 100ae788048087be23e26bb43f868b1fcebb007a
## What changed
- Upgrade `rmcp` and `rmcp-macros` from 3.1.2 to 3.1.3.
- Preserve authentication-required and retryable transport classifications when modern MCP discovery falls back to legacy initialization.
- Prevent unrelated discovery errors from triggering legacy fallback while retaining their diagnostics.
## Testing
- Cover authentication challenges and transient initialization failures during legacy fallback.
- Verify that a failed OAuth issuer check does not consume the pending authorization state.
GitOrigin-RevId: 957c0873fec1148883dd163fbaeb77d7593d8c53
## Why
An authorization server discovered for an MCP server can change. A stored refresh token must not be sent to a different issuer than the one that originally granted it.
## What changed
- Persist the discovered authorization server issuer with new OAuth credentials and preserve it across refreshes.
- Validate that issuer against a single pinned metadata snapshot before refreshing or adopting stored refresh credentials.
- Require reauthentication when refresh credentials have no issuer or the issuer changed. An unexpired access token can still be used without exposing its refresh token.
## Testing
Add coverage for issuer persistence, missing and changed issuers, metadata changes during startup, and refresh-token preservation.
GitOrigin-RevId: 07e48ba892f627428a28bbed5cca4ad703e2a5fd
## What changed
- Require callers to provide an HTTP client for MCP OAuth discovery and login, removing the separate direct `reqwest` path.
- Use the shared `http` and `url` types throughout the MCP client and drop its direct `reqwest` dependency.
- Preserve configured MCP headers when routing OAuth discovery through the provided client.
## Testing
- Add coverage that routed OAuth discovery forwards configured headers.
GitOrigin-RevId: 1345f56bd794626533133447597a5908e57b9b48
## What changed
- Add an opt-in `mcp_2026_07_28` protocol mode while preserving the legacy
lifecycle by default.
- Negotiate the new protocol over streamable HTTP with `server/discover`,
including bounded responses, redirect protection, and fallback only when a
response establishes that the endpoint is legacy-only.
- Require stdio servers to opt in with
`CODEX_MCP_PROTOCOL_VERSION=2026-07-28`, and add a bounded local stdio
transport for the modern lifecycle.
- Consume paginated tool, resource, and resource-template catalogs in modern
mode, reject repeated cursors, and retain discovered server identity.
- Reconnect reusable MCP clients when their selected protocol mode changes.
## Testing
- Cover HTTP JSON and SSE discovery, legacy fallback and rejection cases,
redirects, retries, response limits, and pagination.
- Cover local and executor stdio discovery, protocol markers, message limits,
and legacy compatibility.
GitOrigin-RevId: f6a78816e127d2a482292d63b91c8384f1595903
## Why
Concurrent Codex processes can otherwise refresh the same rotating token, and a
cancelled or partially persisted refresh can leave durable and in-memory MCP
credentials out of sync.
## What changed
- Serialize each credential's read-refresh-write transaction across processes,
reread the authoritative store after locking, and adopt credentials refreshed
by another process.
- Keep refresh persistence running after caller cancellation, bound lock and
provider waits independently, and preserve omitted refresh tokens and scopes.
- Fail MCP startup and operations when refresh or persistence fails instead of
continuing with stale credentials, while requiring reauthorization for
missing, unusable, or rejected refresh tokens.
- Exclude OAuth refresh time from the MCP initialization timeout.
## Testing
Add coverage for lock contention, concurrent refreshes, rejected and missing
credentials, storage failures, caller cancellation, and provider timeouts.
GitOrigin-RevId: 4d29b879bec646d2ceb922b526dc793b1a1f5423
## Summary
- Retry transient streamable HTTP failures during RMCP startup when the
failure happens while sending the initialize request.
- Retry transient streamable HTTP failures for tools/list, which is
read-only and safe to replay.
- Cover both retryable HTTP statuses and request-layer failures where no
HTTP status is returned.
- Surface retryable HTTP statuses from the streamable HTTP adapter as
typed client errors.
- Add integration coverage for initialize retry, tools/list retry,
no-status request failure retry, and non-retryable initialize status.
## Root cause
The observed codex_apps failures can happen before normal tool
execution: RMCP startup fails while sending initialize, or the first
read-only tools/list fails after startup. Retrying hosted_apps_bridge
tools/call would not cover initialize and would risk replaying
side-effecting tool calls. This change retries the streamable HTTP
handshake itself, recreates the transport between initialize attempts,
and retries only tools/list among post-initialize service operations.
## Validation
- cargo fmt --package codex-rmcp-client
- cargo test -p codex-rmcp-client --test streamable_http_recovery
cooper-oai