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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
HomeReleasesv2.1.238entry #192

Claude Code v2.1.238 ·

Calling a tool on a disabled MCP server errors instead of quietly reconnecting

Calling a tool on a disabled MCP server would tell you to re-enable it, but that path is off.

Nothing to try yet In Development
JSON All of v2.1.238
Nothing to try yetTier: how much it should matter to you
2Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
MCPArea: what it touches
In DevelopmentKind: in v2.1.238,
In DevelopmentSection of the release

The disabled-server error only runs when the MCP discovery cache flag is on; otherwise the old quiet reconnect applies.

What

Before reusing a cached or in-flight connection, Claude Code now checks whether the MCP server has been disabled and, if so, fails with text telling you to re-enable it via /mcp to use its tools. This only runs when the MCP discovery cache flag tengu_mcp_discovery_cache_enable is on; otherwise the old behaviour applies.

Details
  • The underlying error is "MCP server disabled".
  • Cached connections are evicted with a recorded reason: "disabled" for user-disabled servers, "policy" for servers blocked by policy.
Evidence

re-enable it via /mcp to use its tools

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

Read from
Names in the bundle/mcp
Feature flag
tengu_mcp_discovery_cache_enable Not enough to say

Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.

This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.238: not a boolean we can read

Read once, for one account on one subscription tier, against v2.1.238. It isn't a statement about your account. What a flag value here can and cannot tell you

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.
The name it cites is new in this buildNew in this build: tengu_mcp_discovery_cache_enable

See this entry in the whole of v2.1.238 →

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