{"version":"2.1.265","anchor":"mcp-tool-permission-checks-now-defer-to-an-sdk-registered-ch","canonical_anchor":"mcp-tool-permission-checks-now-defer-to-an-sdk-registered-ch","heading":"MCP tool permission checks now defer to an SDK-registered checker first","tier":"internal","area":"MCP","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.265\/e\/mcp-tool-permission-checks-now-defer-to-an-sdk-registered-ch","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.265","markdown":"### MCP tool permission checks now defer to an SDK-registered checker first\n\nMCP tool permission checks now consult an SDK-registered checker before the usual permission logic\n\n**What**\n\nWhen deciding whether an MCP tool (a tool provided by an external MCP server) is allowed to run, Claude Code now first asks a permission checker registered by the SDK (software development kit), if one is present. Only if that doesn't produce a decision does it fall back to the built-in permission-rule logic and design-consent checks it used before.\n\n**Why**\n\nThis lets code built on the Claude Code SDK plug in its own custom permission logic for MCP tools, taking priority over the default rules.\n\n- Area: MCP\n- Tier: Under the hood\n- Useful: 2\/5\n- Signal: 1\/5"}