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Sweep 08 Oct 2026 · 18:53Z Build v2.1.295 516 read Stable v2.1.286 Latest v2.1.295 Next v2.1.295 Feeds RSS JSON llms.txt llms-full.txt Unofficial
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Claude Code v2.1.290 ·

MCP tool calls stop instead of hanging when the answer stream ends with no answer

A new per-call watchdog follows each MCP request and aborts the tool call with an error if its answer stream ends without an answer

Group of 2 You'll notice Improvements
JSON All of v2.1.290
You'll noticeTier: how much it should matter to you
3Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
MCPArea: what it touches
ImprovementsKind: in v2.1.290,
ImprovementsSection of the release

Unclear It is not clear which HTTP servers are covered, or whether this tracking is active for anyone.

What

MCP servers are outside programs that give Claude Code extra tools. Each call to one of those tools now has its own watchdog, a check that follows whether the call is still making progress.

  • Tracking: for HTTP MCP servers that match a URL check, sending a request is wrapped so the watchdog learns when the request was sent, when it was taken, and when its answer stream ended. Incoming responses mark the request as answered.
  • Abort instead of hang: if the answer stream ends mid-call with no answer, the tool call aborts with a downstream_unreachable error rather than waiting forever.
  • The call also records claudecode/toolUseId.

Before, the only watchdog watched for transport errors and gave up with "response presumed lost" after 90 seconds.

Why

A tool call whose connection dies should now fail promptly with an error instead of leaving your session stuck. When slow MCP calls time out may also differ from before.

How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtIt is not clear which HTTP servers are covered, or whether this tracking is active for anyone.

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