[campoy]

What was changed

• statelessMcpServer() and statefulMcpServer() references now call invalidateServerToolsCache(name) from @openai/agents-core in invalidateToolsCache(), as native MCP servers do. The agent SDK keeps a shared tool list per server name, and before this change the references never cleared it, so the next run reused the old list.
• A stateful reference also marks its next list-tools Activity with { invalidateToolsCache: true }. The dedicated Worker then calls invalidateToolsCache() on the Worker-side server before it lists, so a factory server with its own cache (cacheToolsList: true) lists again too. Other listings keep their empty input.
• Both are behind patched('openai-agents-mcp-invalidate-tools-cache'), asked only when invalidateToolsCache() is called (and, for a stateless reference, only when it caches).
• New test MCP invalidateToolsCache makes the next run list tools again in test-openai-agents.ts, for both references.

No public API change.

Why?

See #241. After invalidateToolsCache(), the next agent run in the same Workflow still got the old tool names and schemas. No list-tools Activity ran, and nothing warned.

Replay and rollback

The next run after invalidateToolsCache() now schedules a list-tools Activity that it skipped before. Without the gate, an open Workflow that invalidated and then ran the agent again would fail replay with [TMPRL1100].

• Runs recorded before this change replay on it: the gate returns false for them, so they keep the old list.
• Runs that recorded the marker need a build that keeps the gate. The rollback target is a build that asks the same patched() only on replay (workflowInfo().unsafe.isReplaying && patched(...)), so new runs keep the old behavior and marked runs keep the new one. Worker Versioning also works.

Checklist

1. Closes [Bug] openai-agents (TypeScript): invalidateToolsCache() on a plugin MCP server keeps the old tool list #241

2. How was this tested:

   • The new test fails on main at c664a34 on its one assertion: both references get ['old_tool'] after invalidateToolsCache(). It passes with this change. With only the Worker-side part removed, the stateful reference still gets ['old_tool'].
   • Locally in Docker (Node 24.22.0, pnpm 10.27.0): make lint (8 existing warnings, none in changed files), make test (208 passed, 207 on main), make build, check_npm_package.py, smoke.mjs, check_conventions.py and Prettier on the changed files pass.
   • [Bug] openai-agents (TypeScript): invalidateToolsCache() on a plugin MCP server keeps the old tool list #241's reproduction exits 1 on npm 1.24.0 and on main, and 0 with this change.
   • Replay check with a dev server (Temporal CLI 1.9.1), histories recorded with no Workflow cache, stateless and stateful, with and without invalidateToolsCache(), plus stateless runs held open before and after it:
     • main histories replay on main, on this change and on the gate-keeping rollback build (6 of 6 each).
     • This change's histories replay on it and on the rollback build (6 of 6). On main, the 3 with the marker fail with [TMPRL1100] ... Non-deprecated patch marker encountered, as expected for a gate.
     • Without the gate, the 2 main histories that invalidated fail with [TMPRL1100] Activity type of scheduled event 'invokeModelActivity' does not match ... '<server>-list-tools'. That is what the gate prevents.
     • Held runs carried across a Worker change finish with no failed Workflow Task: a main run held after invalidateToolsCache() keeps the old list on this change; one held before it lists again; on the rollback build, a run that recorded the marker lists again and one that didn't keeps the old list. The carried histories replay on this change and on the rollback build.
     • A control with the MCP server renamed fails all 6 main histories with [TMPRL1100].

   CI covers the other Node versions and platforms.

3. Any docs updates needed?
   No. The README doesn't describe MCP tool caching; the agent SDK's MCP guide already says to call invalidateToolsCache().

Not covered

• A stateless factory that returns one shared server instance with its own cache. Each stateless Activity call normally builds a new server, so there is nothing to clear there.
• Open question: the patch ID name. Other gates in this plugin may settle on a naming scheme.

Related: #209 and #210 change the same files (mcp-client.ts, stateful-mcp-client.ts, and #209 the stateful listTools handler in stateful-mcp-provider.ts). Whichever merges second needs a small rebase.