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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

Claude Code v2.1.304 ·

SDK hosts can mark MCP tools that run code, so auto mode checks them

The SDK initialize request accepts codeRunningMcpTools so auto mode judges code-running MCP tools, and the reply reports whether it applied

Group of 3 Use it now New Features
JSON All of v2.1.304
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New FeaturesKind: in v2.1.304,
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Unclear Exactly which permission rules are removed when tools are marked this way is not stated.

What

MCP tools are tools supplied by outside servers that Claude Code connects to. Programs that run Claude Code through the SDK, its programming interface, set it up with an initialize request. That request now accepts an internal field, codeRunningMcpTools:

  • It maps each MCP server name to a list of tool names on that server that run code Claude wrote.
  • Entries in the wrong shape are ignored with a warning. Valid entries cause Claude Code to rebuild its permission settings.
  • In auto mode, where Claude Code approves actions on its own, a checker now judges calls to these tools.
  • An allow answer from a PermissionRequest hook (a user command that decides on a permission question) no longer switches the permission mode for these tools.
  • The initialize reply now includes code_running_mcp_tools_applied, and plugins_applied falls back to the value resolved earlier.
  • The description of the file_attachments field adds a note about claude-code-server.

Why

An MCP tool that runs code could otherwise slip past auto mode's checks. Hosts can now declare such tools so their calls are judged like other code execution.

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 doubtExactly which permission rules are removed when tools are marked this way is not stated.

See this entry in the whole of v2.1.304 →

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