# #26672 runtime transcript, fix head 31263d011e

Server: `node apps/server/src/bin.ts serve --port 47826 --host 127.0.0.1 --base-dir <fresh scratch home>` (empty database, T3CODE_DEV_SEED=0), one scratch git project.
Driver: `t3 thread start --provider claudeAgent --model claude-sonnet-5-5 --wait --json <project> - < msg.txt`, a real Claude Code agent calling the server's MCP tools.

## Prompt (msg.txt)

```
This is a test of T3's MCP argument validation. Do exactly these two tool calls, nothing else, then reply with each call's raw result verbatim (error text or JSON), labelled CALL 1 and CALL 2.
CALL 1: the T3 MCP tool t3_thread_launch with exactly these arguments: {"title": "Repro: prompt instead of message", "scratch": true, "prompt": "say hi"}
CALL 2: the T3 MCP tool t3_thread_launch with exactly these arguments: {"title": "Repro: message", "scratch": true, "message": "say hi"}
Do not correct, rename or drop any argument key in CALL 1, even if you expect it to fail.
```

## Agent reply (verbatim)

**CALL 1** (error):
```
Invalid parameters for tool 't3_thread_launch': Unknown argument "prompt". Accepted arguments: environmentId, projectId, scratch, title, modelSelection, runtimeMode, interactionMode, workspaceStrategy, message, attachments, clientRequestId, delegatedFrom.
```

**CALL 2** (result):
```json
{"threadId":"mcp:cf69b70e-3352-4869-b59d-685b153884da","link":"<t3-thread://v2/e4a64418-3700-4d3c-b566-a30ff02fab65/mcp:cf69b70e-3352-4869-b59d-685b153884da>","projectId":"f61b9b30-c063-4076-864d-41a8e34c4a31","modelSelection":{"instanceId":"claudeAgent","model":"claude-sonnet-5-5"},"runId":"run:thread:mcp%3Acf69b70e-3352-4869-b59d-685b153884da:ordinal:1","status":"preparing"}
```

## Follow-up: `t3 thread show` on the CALL 2 thread

status completed, runCount 1, latestRunId run:thread:mcp%3Acf69b70e-3352-4869-b59d-685b153884da:ordinal:1