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 v2.1.247 Home All releases olderv2.1.246 v2.1.248newer
Claude Code v2.1.247

Session-channel messages from senders this session cannot verify are refused, dropped or trimmed

Under the hood
Useful2 Signal4
Remote Tools

Session-channel messages from unverified senders are dropped, and untrusted settings changes get their plugin key stripped.

What

Certain sensitive messages arriving over the session channel are judged against a device-attestation floor, and a message with no stamp is treated as refused. Below-floor requests are dropped without an answer, below-floor replies are dropped so the original request keeps waiting, and a below-floor settings change has only its forwarded-plugin key removed while the rest applies.

Details
  • Guarded message kinds are the tool announcement, hook registration, hook template upload and settings application.
  • A below-floor refusal of a call is rebuilt with the target name unverified-sender and a plain-language reason, so Claude is told the result is unconfirmed rather than being told the call failed.
  • Whether each family is guarded is decided at runtime by the matching admission checks (CLAUDE_CODE_DISABLE_HOOK_FORWARDING, CLAUDE_CODE_DISABLE_PLUGIN_FORWARDING, session channel off, hermetic mode); with no judgement available all three are guarded.
Evidence

reported refused \u2014 ${e} \u2014 by a sender this session could not verify; whether anything ran there is not confirmed. Check its effect before re-running it.

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

Related

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

See this entry in the whole of v2.1.247 →