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Sweep 01 Oct 2026 · 17:27Z Build v2.1.287 508 read Stable v2.1.285 Latest v2.1.287 Next v2.1.287 Feeds RSS JSON llms.txt llms-full.txt Unofficial
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Claude Code v2.1.286 ·

Turning MCP servers on or off from a controlling program handles SDK servers apart

Requests to switch an MCP server on or off now check their inputs, treat SDK-provided servers separately and refuse servers that policy blocks

You'll notice Improvements
JSON All of v2.1.286
You'll noticeTier: how much it should matter to you
2Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
SDKArea: what it touches
ImprovementsKind: in v2.1.286,
ImprovementsSection of the release
What

A program that drives Claude Code, such as one built with the Claude Agent SDK, can send a request to switch an MCP server (an outside program that gives Claude extra tools) on or off. Handling of that request has changed:

  • The server name must be text and the on/off value must be true or false, or the request is rejected with a message such as mcp_toggle: serverName must be a string.
  • Servers supplied by the SDK program itself are handled separately from other servers.
  • Switching on a server that policy blocks is refused.
  • Switching on a registered SDK server is handled as a control request to the driving program.
Why

This affects programs that control Claude Code and manage MCP servers through it.

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 whether this handling is new behaviour or existing behaviour moved elsewhere.

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