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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

Server instructions truncation moved behind a helper

Under the hood

Useful1 Signal0

MCP

Long MCP server instructions are still trimmed the same way, just through shared code now.

What

The inline truncation of long MCP server instructions was replaced by a shared helper, with no intended change to connect behaviour.

Details

The helper applies the same length limit and suffix, and only logs the truncation when a server name is supplied.
Tool-listing bookkeeping switched from a WeakMap of started/applied counters to a dedicated helper plus a module-level { last: void 0 } record.

Evidence

… [truncated], mcp_connect_complete

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 →