Source Intelligence

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

All of v2.1.239 Home All releases olderv2.1.238 v2.1.240newer
Claude Code v2.1.239

Placeholder MCP tools so old transcripts still render

Not switched on
Useful2 Signal3
MCP

Disconnected MCP tools could show proper names in old transcripts instead of blanks, but not yet.

Placeholder MCP tool objects are built only behind a flag defaulting false plus a control-channel condition.

Feature flag
tengu_violin_wood Off in both readings

The flag server returned off for the account this site reads and for the anonymous baseline. A reading of off cannot rule out a rollout these two readings sit outside of.

This account: off · anonymous baseline: off · compiled default in v2.1.239: on

Read once, for one account on one subscription tier, against v2.1.239. It isn't a statement about your account. What a flag value here can and cannot tell you

What

A stand-in tool object can be built for an MCP tool that is no longer connected, purely so past transcript entries display a proper ${t} - ${r} (MCP) name and result instead of a blank. It can never be called: every entry point throws. Built only when the tengu_violin_wood flag is on, whose fallback is false, and a remote/control-channel condition also holds, so it is inert in this build.

Details
  • Result text is stripped of OSC-8 terminal hyperlinks, other escape sequences and control characters before display.
  • Calling one yields Display-only MCP tool invoked \u2014 it exists only for transcript rendering.
Evidence

Display-only MCP tool invoked \u2014 it exists only for transcript rendering

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.239 →