Alex Kotliarskyi 0650d6d1ca Preserve MCP authentication challenges on tool calls (#42552) ...

## Why

When silent OAuth refresh cannot recover a rejected MCP tool call, the caller
needs the server's authentication challenge to initiate interactive login. The
rejected call must not be replayed automatically after refresh has failed.

## What changed

- Convert `401 Unauthorized` responses with `WWW-Authenticate` headers into an
  MCP tool error containing `mcp/www_authenticate` metadata.
- Preserve multiple authentication challenges by combining all
  `WWW-Authenticate` header values.
- Keep successful silent refresh behavior while avoiding replay when refresh
  fails.

## Testing

Added coverage for successful and failed refresh, multiple authentication
headers, propagation through agent tool-call events, and no-replay behavior.

GitOrigin-RevId: c560cff6286d7ab09b1f5c6cf3618d4650cde47d

2026-09-03 15:12:02 +00:00

..

foreign_stdio_cwd.rs

mcp: accept foreign absolute cwd for remote stdio (#29493)

2026-06-23 01:33:51 +00:00

mcp_2026_discovery.rs

Update rmcp to 3.1.3 (#39798)

2026-08-20 20:53:17 +00:00

mcp_2026_message_limits.rs

Complete MCP 2026 client support (#35725)

2026-07-28 06:06:58 +00:00

mcp_2026_mrtr.rs

Update rmcp to 3.1.2 (#39101)

2026-08-17 23:04:09 +00:00

mcp_2026_oauth_discovery.rs

Harden MCP OAuth callback handling (#40691)

2026-08-25 20:26:23 +00:00

mcp_2026_sse_discovery.rs

Add MCP 2026-07-28 discovery support (#35724)

2026-07-28 05:52:12 +00:00

mcp_2026_stdio_discovery.rs

Propagate custom CA settings to local MCP servers (#38040)

2026-08-11 17:24:04 +00:00

mcp_2026_stdio.rs

Fix relative MCP server spawning on macOS (#42117)

2026-09-01 18:53:06 +00:00

mcp_events.rs

Add MCP event discovery and subscriptions (#37494)

2026-08-07 19:36:52 +00:00

process_group_cleanup.rs

Fix relative MCP server spawning on macOS (#42117)

2026-09-01 18:53:06 +00:00

resources.rs

Improve sandboxing, MCP errors, and cached approvals (#41196)

2026-08-27 20:05:08 +00:00

stdio_message_limits.rs

Harden local MCP server process tree cleanup (#37366)

2026-08-07 03:34:49 +00:00

streamable_http_oauth_startup.rs

Preserve MCP authentication challenges on tool calls (#42552)

2026-09-03 15:12:02 +00:00

streamable_http_oauth_store_pinning.rs

Enable coordinated MCP OAuth refresh (#42413)

2026-09-03 02:00:12 +00:00

streamable_http_recovery.rs

Preserve MCP authentication challenges on tool calls (#42552)

2026-09-03 15:12:02 +00:00

streamable_http_remote.rs

Cache executor metadata from initialization (#40343)

2026-08-24 06:43:07 +00:00

streamable_http_test_support.rs

Enable coordinated MCP OAuth refresh (#42413)

2026-09-03 02:00:12 +00:00

streamable_http_user_agent.rs

Set a default user agent for MCP HTTP requests (#34883)

2026-07-23 06:13:12 +00:00