{"version":"2.1.221","anchor":"mcp-schema-validator-strips-known-meta-schema-schema-keys","canonical_anchor":"mcp-schema-validator-strips-known-meta-schema-schema-keys","heading":"MCP schema validator strips known meta-schema $schema keys","tier":"notice","area":"MCP","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.221\/e\/mcp-schema-validator-strips-known-meta-schema-schema-keys","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.221","markdown":"### MCP schema validator strips known meta-schema $schema keys\n\nMCP tools that declare a standard $schema no longer fail validation over that one key.\n\n**What**\n\nA wrapper around the JSON-schema validator removes the `$schema` property when it names a recognised meta-schema and validates the remainder, so MCP tools declaring a standard $schema do not trip validation on that key.\n\n**Details**\n\n- A trailing `#` on the meta-schema URI is tolerated.\n- Only recognised meta-schema values are stripped; anything else is left in place.\n- Whether this path is reached on every validation could not be resolved from the build.\n\n**Evidence**\n\n`$schema`\n\n- Area: MCP\n- Tier: You'll notice\n- Useful: 3\/5\n- Signal: 0\/5"}