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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.

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Claude Code v2.1.221 3 Aug 2026

MCP: server/discover answered from the cached projection on the stateless proxy

Under the hood

Useful2 Signal0

MCP

Some MCP server discovery calls are answered from cache, avoiding an extra round trip.

What

The stateless claudeai-proxy path, which already short-circuited initialize from a cached projection, now does the same for server/discover.

Details

It either replies with the cached result or synthesises a JSON-RPC "Method not found" error for servers known to be legacy, without a round trip.
Both cases are logged.

Evidence

Stateless claudeai-proxy — server/discover resolved locally as legacy (method-not-found), server/discover resolved locally as legacy (method-not-found)

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

See this entry in the whole of v2.1.221 →