## What changed
Extend `mcp_connection_sharing` to pool compatible local stdio connections that negotiate MCP `2026-07-28`. Keep legacy servers and servers that request input during startup private.
Preserve each chat's tool catalog and route input requests to the calling chat. Release connections independently for each chat, shutting down the shared server after the final release, and retire pooled connections on forced refresh without interrupting other chats.
## Testing
Add pool, runtime, app-server, and core scenario tests covering protocol gating, startup cancellation, refresh, final-release shutdown, and separate tool visibility and simultaneous input responses across chats sharing one process.
GitOrigin-RevId: 896b107267a20ec1bffccdefca6c40fe2945a022
## Why
MCP tool discovery discarded response-level `_meta`, leaving server-status clients unable to inspect metadata associated with the tool catalog.
## What changed
- Preserve opaque `_meta` from the first `tools/list` page through catalog refreshes and caches.
- Expose it as `toolListMeta` in `McpServerStatus`, with `null` when unavailable, and update generated schemas and bindings.
- Scope cached Apps catalog metadata to discovery settings, including client capabilities and extensions, while retaining tools from older caches without metadata.
- Restrict server capabilities in status snapshots to the selected servers.
## Testing
Add regression coverage for listing legacy cached Apps tools during failed startup, and update protocol serialization expectations for nullable `toolListMeta`.
GitOrigin-RevId: 62335e2fd8c482067a7a78a7612b58c3eaa9fb55
## 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
## Why
Idle Apps clients and cached MCP bindings can retain replaced tool definitions. Shared catalog updates can also invalidate prepared calls even when the current definitions match the captured catalog, including after tools are restored while a call awaits approval.
## What changed
- Share immutable tool arrays across equivalent live discovery contexts and reuse storage for equal results. Let unused providers and cached bindings expire.
- Include requested capabilities and initialization results in the sharing scope, and detach servers that disable catalog caching from live sharing.
- Capture catalog snapshots for prepared calls. Accept equivalent shared catalogs regardless of tool-list order, while rejecting changed definitions and calls captured before an explicit refresh on that client.
## Testing
Add regression coverage for shared storage and scope isolation, release of replaced tools and unused bindings, equivalent catalog restoration, explicit refresh invalidation, and an Apps call completing after catalog restoration while awaiting approval.
GitOrigin-RevId: a0516186e4286d0ff13405fafbab6fcf3f1f3773
## Why
Refreshing installed Apps without a thread should update the tools available to existing threads on their next turn.
## What changed
- Publish live tool catalogs to clients with matching transport, auth, protocol, and listing settings within the same account and home directory. Ignore the thread attribution header when matching scopes.
- Adopt updated tools before catalog reads and new calls, preserving running calls and rejecting calls prepared against an outdated catalog revision.
- Keep the newest successful fetch per scope so older refreshes cannot overwrite newer tools, and exclude disk snapshots from live updates.
## Testing
Add regression coverage for refresh propagation to an existing thread without another tools listing, scope and account isolation, out-of-order refreshes, late client startup, and running versus stale prepared calls.
GitOrigin-RevId: 7a5ee34e23742ce374c6647dc8928b76ea622448
## Why
Refreshed Apps catalogs need to survive connection reuse. Catalog revisions scoped to the connection set can lose refreshed tools during reconciliation and invalidate prepared calls for unrelated servers.
## What changed
- Store tools, revisions, and refresh coordination on each MCP client, and key cached bindings by client identity and revision.
- Preserve existing binding snapshots while rejecting stale calls before preparation. Wait for active calls to finish before publishing a refreshed catalog.
- Add `CodexThread::refresh_codex_apps_tools` to reconcile the runtime and return the refreshed client's raw Apps inventory alongside tool names eligible under that runtime's generic MCP policy. Keep hidden and disabled tools in the inventory for callers to apply app-specific policy.
## Testing
Add regression coverage for refreshed catalogs surviving client reuse, unrelated calls remaining valid, binding cache invalidation, and refresh snapshots retaining the client's own inventory when another client wins the shared-cache race. Update stale-call and preparation tests to use client-owned catalogs.
GitOrigin-RevId: f2308c81f7474eb31f3380c091c977030123cda2
Charlie Marsh