Claude Code v2.1.118 ·
MCP Tool Hooks (mcp_tool)
EntryKind: in v2.1.118,
ChangesSection of the release
What
A new hook type that invokes an MCP server tool as the hook action, as an alternative to bash/command hooks.
Details
- Configure with
type: "mcp_tool" in hook definitions - Specify
server (name of an already-configured MCP server) and tool (tool name on that server) - Supports
arguments object with ${path} interpolation from hook input JSON - Optional
timeout field for per-call timeout in seconds - Reads
X-Mcp-Error-Code header from 401 responses for better error diagnostics - Not available for all hook events — logs
"mcp_tool hooks are not available for the '<event>' hook event" when unsupported
Evidence
Hook type definition (search for "mcp_tool") and MCP tool schema fields (search for "Name of an already-configured MCP server to invoke").
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
One source agreesOne thing we can check says the same as this entry.
Anthropic's release notes agreeHooks can now invoke MCP tools directly via type: "mcp_tool"
See this entry in the whole of v2.1.118 →
