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Sweep 06 Nov 2026 · 01:32Z Build v2.1.319 537 read Stable v2.1.311 Latest v2.1.318 Next v2.1.319 Feeds RSS JSON llms.txt llms-full.txt Unofficial
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Claude Code v2.1.309 ·

MCP config files are tracked, and a host can hand over a ready-made tool listing

--mcp-config file paths are now recorded and registered, and an MCP config can carry a pre-supplied tool listing so discovery can be skipped

Group of 4 Use it now Internal Changes
JSON All of v2.1.309
Use it nowTier: how much it should matter to you
4Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
MCPArea: what it touches
Internal ChangesKind: in v2.1.309,
What probably matters to youSection of the release

What

MCP servers are outside programs that give Claude Code extra tools. --mcp-config is the option that loads them from JSON files or strings. Two related things changed in how this configuration is read:

  • File paths: the paths of files given to --mcp-config are now kept for the whole session (flagMcpConfigFilePaths, cleared on reset). For each one that is a file, both the path and its real location on disk are collected and passed to a new registration step, which checks them against the scan of allowed folders. Before, the file was read with no path registration.
  • Handed listings: a server's config can now include a handed_listing string next to its url. The parser returns these as handedListings, and startup passes them on as handedMcpListings. In headless mode, a listing (its startup handshake plus tools_list, with an at timestamp) is accepted only for a dynamic http server whose URL matches. A listing older than 600 seconds is dropped. When connecting, cached servers can now have their capabilities, server details and instructions filled from a stored handshake. What supplies this data and whether it is switched on was not traced.

Why

A program hosting Claude Code can hand over a server's tool list ahead of time, so Claude Code can skip asking the server for it, which affects how quickly tools are available at startup.

Read from
Names in the bundle--mcp-config
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.

Confirmed since Anthropic's documentation has since written up --mcp-config, on Choose a permission mode. * A file you passed to [`--settings`](https://code.claude.com/docs/en/cli-reference#cli-flags), `--mcp-config`, or `--agents` when you started the session permission-modes see the edit
Added since A small documentation edit on Manage Claude Code plugins for your organization touched a line naming --mcp-config after this was published. | `disableSideloadFlags` | Rejects `--plugin-dir`, `--plugin-url`, `--agents`, the Agent SDK `plugins` option, and folders named in the [`CLAUDE_CODE_PLUGIN_DIRS`](https://code.claude.com/docs/en/env-vars#variables) variable at startup, an… plugins/org see the edit
How sure we are
Two sources agreeTwo things we can check say the same as this entry.
Anthropic's documentation agreesA small documentation edit on Manage Claude Code plugins for your organization touched a line naming --mcp-config after this was published.
Anthropic's release notes agreeFixed sandboxed commands and auto-accepted edits being able to modify the MCP config file passed with --mcp-config

See this entry in the whole of v2.1.309 →

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