{"version":"2.1.224","anchor":"mcp-client-version-mismatch-now-reports-before-it-throws","canonical_anchor":"mcp-client-version-mismatch-now-reports-before-it-throws","heading":"MCP client version mismatch now reports before it throws","tier":"internal","area":"MCP","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.224\/e\/mcp-client-version-mismatch-now-reports-before-it-throws","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.224","markdown":"### MCP client version mismatch now reports before it throws\n\nAn MCP client version mismatch now reports the two versions before raising its error.\n\n**What**\n\nWhen the MCP runtime resolves to one client generation but the loaded module is from the other, a once-per-process `tengu_mcp_tripwire` event is emitted, carrying the expected and loaded generations (normalised to v1, v2 or other), immediately before the existing error is raised. The event name was added to the allow-listed list.\n\n**Evidence**\n\n`tengu_mcp_tripwire`\n\n- Area: MCP\n- Tier: Under the hood\n- Useful: 2\/5\n- Signal: 2\/5"}