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 v2.1.128 Home All releases olderv2.1.126 v2.1.129newer

MCP Tool Search Handles Late-Connecting Servers Better [Gradual Rollout]

Feature flag
tengu_ashen_kelp On for this account, and not off by default

The flag server returned on for the one account this site reads, and nothing in this release compiles it off by default. The compiled default is shown below, and says which it is when we cannot read one: a fifth of gates compile in a string or a number rather than on or off, and most published releases have no gate table behind them at all. No client can see what the server returns for your account.

This account: on · anonymous baseline: on · compiled default in v2.1.128: no gate table built for this version

These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.

Read once, for one account on one subscription tier, against v2.1.128. It isn't a statement about your account. What a flag value here can and cannot tell you

Tool search can now refresh MCP clients and retry selection/search when matching tools may still be arriving from connecting servers.

Details
  • When enabled, direct select:<tool_name> can retry after an MCP refresh.
  • Keyword searches can also refresh before declaring that no tools match.
  • Claude receives clearer guidance that connecting MCP servers may expose tools shortly.
  • This behavior is gated by tengu_ashen_kelp.
Evidence

Deferred tool refresh behavior (search for "ToolSearchTool: partial select after MCP refresh" and "tengu_ashen_kelp")

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

See this entry in the whole of v2.1.128 →