{"version":"2.1.310","anchor":"mcp-changes-new-telemetry-keys-tool-name-parsing-env-var","canonical_anchor":"mcp-changes-new-telemetry-keys-tool-name-parsing-env-var","heading":"MCP tool names are read more flexibly and server settings are checked by value","tier":"internal","area":"MCP","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.310\/e\/mcp-changes-new-telemetry-keys-tool-name-parsing-env-var","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.310","markdown":"### MCP tool names are read more flexibly and server settings are checked by value\n\nClaude Code now tries a second way to read MCP tool names and checks MCP server environment variables by their value as well as their name\n\n**Unclear.** Which MCP tool names or environment variable values are now accepted or rejected that were not before is not stated.\n\n**What**\n\nMCP (Model Context Protocol) is the way Claude Code connects to outside tools and services, called MCP servers. Several parts of how Claude Code handles them changed:\n\n- Tool names starting with `mcp__` are now read by a second method when the first one cannot make sense of the name.\n\n- Environment variables set for an MCP server (settings passed to the server program when it starts) are now checked using their value as well as their name. Before, only the name was checked.\n\n- Two new labels for recording MCP errors or steps were added, one for standard keys and one for desktop connector names.\n\n**Why**\n\nThis shifts how Claude Code recognises MCP tool names and which server environment variables it accepts, so a setup that relies on unusual tool names or variable values may behave differently.\n\n- Area: MCP\n- Tier: Under the hood\n- Useful: 2\/5\n- Signal: 2\/5\n- Scope: individual\n- Heads-up: no"}