[Bug]: t3_queue reorder can't move a message to the end: the advertised schema drops null from beforeRunId #30303

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/desktop

Steps to reproduce

1. Queue two or more messages on a thread.
2. From an agent, call the MCP tool t3_queue with action: "reorder" and beforeRunId: null, as its description says ("reorder: before beforeRunId, or to the end with null").
3. Look at the input schema T3 advertises for t3_queue.

Expected behavior

beforeRunId is advertised as string or null, and null moves the message to the end of the queue.

Actual behavior

The advertised schema has beforeRunId: { "type": "string" }. QueueTool declares beforeRunId: Schema.optional(Schema.NullOr(RunId)) (apps/server/src/mcp/toolkits/thread/tools.ts:99), and compact in apps/server/src/mcp/advertisedJsonSchema.ts (#25423) drops the null branch of optional properties. So an agent that follows the schema can't send null. Ours sent the string "null", which the server read as a run id and answered "Failed to reorder". The handler still treats null as "to the end", so only the advertised schema is wrong. advertisedJsonSchema.test.ts covers a required NullOr field, not this optional one.

Possible fix: keep the null branch when null has a meaning (here beforeRunId), and add this shape to advertisedJsonSchema.test.ts.

Impact

Major degradation or frequent failure

Version or commit

main @ a760f37

Environment

No response

Logs or stack traces

Failed to reorder

Screenshots, recordings, or supporting files

No response

Workaround

Move each message queued after it to before it, one by one.