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Sweep 22 Sep 2026 · 17:19Z Build v2.1.280 501 read Stable v2.1.267 Latest v2.1.280 Next v2.1.280 Feeds RSS JSON llms.txt Unofficial
Claude Code v2.1.257 ·

New MCP connection error messages

MCP connection failures now say when a server is not approved for the project, pointing you at /mcp, or when the account changed.

TierYou'll noticehow much it should matter to you
Useful2my rating, 1 to 5
Signal1worth watching, 1 to 5
AreaMCPwhat it touches
KindNew Featuresin v2.1.257,
You'll notice

MCP connection failures now say when a server is not approved for the project, pointing you at /mcp, or when the account changed.

Two new messages are shown for MCP server connection failures: one tells you a server is "Not approved for this project" and directs you to run /mcp to approve it, and the other reports that the account changed mid-connection.

Read from
Names in the bundle/mcp
Since it was published

The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.

Added since A small documentation edit on Channels reference touched a line naming /mcp after this was published. * **`curl` succeeds but nothing reaches Claude**: run `/mcp` in your session to check the server's status. A `failed` status usually means a dependency or import error in your server file. To see the stderr trace, restart with `claude --de… channels-reference see the edit
Confirmed since Anthropic's documentation has since written up /mcp, on Third party connectors with remote MCP. **MCP server URL**: the HTTPS address where the server accepts MCP requests, for example `https://mcp.example.com/mcp`. After you continue, Claude checks the URL and pre-fills the authentication settings it detects, marked "Detected." connectors/custom/remote-mcp see the edit
How sure we are
Two sources agreeTwo things we can check say the same as this entry.
Anthropic's documentation agreesAnthropic's documentation has since written up /mcp, on Third party connectors with remote MCP.
Anthropic's release notes agreeFixed /mcp reconnect and enable still connecting a settings-file MCP server that a managed MCP allow/deny list or…

See this entry in the whole of v2.1.257 →

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