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Sweep 19 Sep 2026 · 02:36Z Build v2.1.278 500 read Stable v2.1.267 Latest v2.1.278 Next v2.1.278 Feeds RSS JSON llms.txt Unofficial
Claude Code v2.1.274 ·

sse-ide and ws-ide MCP server types are now treated as host-only

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Claude Code now blocks adding sse-ide/ws-ide (and sdk) MCP servers to config and routes them into the blocked list during server-set updates, since these are managed by the host app, not stored config.

TierYou'll noticehow much it should matter to you
Useful2my rating, 1 to 5
Signal1worth watching, 1 to 5
AreaMCPwhat it touches
KindImprovementsin v2.1.274,
Group of 2 You'll notice

Claude Code now blocks adding sse-ide/ws-ide (and sdk) MCP servers to config and routes them into the blocked list during server-set updates, since these are managed by the host app, not stored config.

What

  • Adding an MCP server via config now checks its transport type against a host-only set (sdk, sse-ide, ws-ide) and throws a clear error explaining that such servers are registered by the host application at runtime and can't be stored in configuration.
  • When processing an mcp_set_servers update, servers of type sse-ide or ws-ide are now routed into the blocked/dropped map alongside already-registered names, instead of falling through to the general allow/block logic.

Why These transport types represent servers that only make sense as live, host-managed connections (such as an IDE's own SSE/WebSocket endpoint), so storing or generally allow/block-listing them as regular config entries doesn't make sense; this change makes that restriction explicit and consistent.

Read from
Names in the bundlesdksse-idews-ide
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 Log at info level touched a line naming sdk after this was published. For long-running agentic tasks, the TypeScript and Ruby tool runners support automatic [compaction](https://platform.claude.com/docs/en/build-with-claude/context-editing#client-side-compaction-sdk), which generates summaries when token usa… agents-and-tools/tool-use/tool-runner see the edit
Confirmed since Anthropic's documentation has since written up sdk, on Error reference. You tried to switch [output styles](/docs/en/output-styles) with `/output-style <style>` or `/config outputStyle=<style>` in a session whose setting sources exclude `local`. Examples are an [Agent SDK](/docs/en/agent-sdk/typescript) sessio… errors see the edit
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agreesAnthropic's documentation has since written up sdk, on Error reference.

See this entry in the whole of v2.1.274 →