## Why
MCP servers can expose new tools during discovery. Refreshing the catalog after a tool-list notification lets Codex discover and call those tools in the same turn.
## What changed
- Add the disabled-by-default `mcp_tool_list_changed` feature for ordinary MCP servers.
- Track notifications in transport order and refresh catalogs before subsequent discovery or tool binding. Coalesce concurrent refreshes and retry listings invalidated by notifications, including during pagination.
- Retain the previous catalog on refresh failure, apply a retry cooldown, and invalidate affected startup caches. Allow notification refreshes to proceed while admitted calls finish.
## Testing
Add coverage for same-turn discovery and invocation in direct and Code Mode, notifications during startup and pagination, disabled behavior, cache invalidation, and concurrent refreshes with timeout recovery.
GitOrigin-RevId: 9afee8deba00dd9851b5f32625f61f96965aa00c
jif
0df4aa6778