{"version":"2.1.310","anchor":"mcp-tool-names-translated-to-a-standard-key-behind-tengu-m","canonical_anchor":"mcp-tool-names-translated-to-a-standard-key-behind-tengu-m","heading":"MCP tool names can be translated to a new standard form","tier":"internal","area":"MCP","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.310\/e\/mcp-tool-names-translated-to-a-standard-key-behind-tengu-m","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.310","markdown":"### MCP tool names can be translated to a new standard form\n\nBehind a remote switch, Claude Code can rewrite MCP tool names to a standard form in what it sends and receives, and remembers old names\n\n**Unclear.** It is not clear what the standard names look like or whether existing permission rules for MCP tools are updated to match.\n\n**What**\n\nMCP is the protocol Claude Code uses to connect to outside tools. New code can rewrite the names of MCP tools into a standard form in what Claude Code sends to the model and what comes back. This covers:\n\n- tool calls and tool references\n\n- tool definitions\n\n- the choice of which tool to use\n\n- tools excluded through `context_management`\n\nFor each server, Claude Code records which servers keep their older names, under `mcpLegacyKeyOwners` in its configuration. All of this runs only when the remote switch `tengu_marlin_thicket` is on.\n\n**Why**\n\nIf it is switched on, MCP tool names may look different to the model and to permission rules you have written for existing MCP servers.\n\n- Flag `tengu_marlin_thicket`: Not enough to say (read for one account on one subscription tier against v2.1.310; this account: no value returned, anonymous baseline: no value returned, compiled default: off) These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.\n- Area: MCP\n- Tier: Under the hood\n- Useful: 3\/5\n- Signal: 4\/5\n- Scope: individual\n- Heads-up: no"}