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Sweep 22 Oct 2026 · 04:32Z Build v2.1.308 527 read Stable v2.1.308 Latest v2.1.308 Next v2.1.308 Feeds RSS JSON llms.txt llms-full.txt Unofficial
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Claude Code v2.1.219 ·

MCP connection failures can carry an extra display detail

Failed MCP connections now tell you why, with the error detail shown in list and get output.

You'll notice New Features
JSON All of v2.1.219
You'll noticeTier: how much it should matter to you
4Useful: my rating, 1 to 5
0Signal: worth watching, 1 to 5
MCPArea: what it touches
New FeaturesKind: in v2.1.219,
What probably matters to youSection of the release
What

Failed MCP connections can now attach a displayDetail explaining why, and the CLI surfaces it instead of just showing a bare status.

Details
  • displayDetail is optional, threaded through the failure constructor and appended to the user-visible error.
  • The Authorization-header rejection path attaches Error detail: plus the server response body when that body is non-empty.
  • claude mcp list builds its status line as the status, an em dash and the issue; claude mcp get prints an Issue: line.
  • The "! Connected · tools fetch failed" status now carries the underlying error as its issue.
Evidence

displayDetail

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

Read from
Names in the bundleclaude mcp listclaude mcp get
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's release notes agreeAdded HTTP status and error text to claude mcp list and /mcp when a server fails to connect, and a warning for MCP config values with hidden…

See this entry in the whole of v2.1.219 →

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