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Sweep 22 Sep 2026 · 17:19Z Build v2.1.280 501 read Stable v2.1.267 Latest v2.1.280 Next v2.1.280 Feeds RSS JSON llms.txt Unofficial
Claude Code v2.1.274 ·

mcp_server field added to tool permission event schemas

Tool permission events now record which MCP server a tool belongs to

TierUnder the hoodhow much it should matter to you
Useful1my rating, 1 to 5
Signal1worth watching, 1 to 5
AreaPermissionswhat it touches
KindInternal Changesin v2.1.274,
Under the hood

Tool permission events now record which MCP server a tool belongs to

What

The event schemas used for tool-use permission requests, denials, and asks (which record things like tool_name, tool_input, tool_use_id, and permission_suggestions) now include an optional mcp_server field. A new helper function fills this field in by looking up the tool in the MCP (Model Context Protocol) tool registry when a permission decision is made.

Why

This lets permission-related records show which MCP server a tool came from, which is useful for tracking or auditing permission decisions involving tools provided by MCP servers rather than built-in tools.

See this entry in the whole of v2.1.274 →

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