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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 ·

New MCP tool metadata field describing the serving MCP server

MCP tools now carry structured metadata identifying which server and source they came from, for security purposes

TierUnder the hoodhow much it should matter to you
Useful2my rating, 1 to 5
Signal1worth watching, 1 to 5
AreaMCPwhat it touches
KindInternal Changesin v2.1.274,
Under the hood

MCP tools now carry structured metadata identifying which server and source they came from, for security purposes

What

Tools provided by MCP (Model Context Protocol) servers now carry structured metadata describing the server that's serving them: the server's configuration key name, and a source value drawn from a fixed set of options (sdk, plugin, user, project, local, dynamic, managed, enterprise, claudeai, agent) describing where that server's definition came from. The tool-wrapper builder now threads this source value through into the tool's metadata.

Why

The metadata explicitly instructs consumers to trust the source field, not the tool's name or its mcp__ prefix, for security purposes. This closes a gap where a tool's name or prefix alone could be spoofed or misleading about where it actually came from.

See this entry in the whole of v2.1.274 →

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