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 v2.1.224 Home All releases olderv2.1.223 v2.1.225newer

MCP stdio connections remember how the last child process ended

Under the hood
Useful2 Signal2
MCP

Reconnects to a local MCP server now know whether the previous process exited or was killed.

What

When an MCP server started over stdio is torn down, Claude Code now records whether its process had already exited or was still running, and the reconnect path reads that back on the next automatic connect. This gives reconnection a view of whether the previous server died or was killed mid-flight.

Details
  • Keyed by a hash over the command, working directory, sorted environment and arguments, so each distinct server configuration gets its own record.
  • Recorded only if the transport had finished starting; the outcome is stored as "hard_closed" for an already-exited child or "survived" for a live one.
  • The entry is deleted once consumed. The map is capped and evicts oldest-first.
Evidence

hard_closed

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

See this entry in the whole of v2.1.224 →