Scan MCP inputSchema or outputSchema JSON for external references that should not be automatically fetched by implementations.
Current MCP tool schemas support JSON Schema references, but implementations must not blindly auto-dereference external $ref URIs. This scanner only reports references; it never fetches them.
Find internal and external $ref values in MCP tool schemas without fetching or dereferencing remote schemas.
Use MCP External $ref Scanner as a focused pre-flight utility while building, reviewing or debugging an MCP integration. Paste the relevant configuration, protocol message, metadata, schema or value into the tool and review the returned findings before the same data reaches a production client or server.
Use the findings as a pre-deployment security review rather than as proof that an MCP server is safe. Security depends on runtime isolation, authorization, deployment policy and the behavior of the connected tools and systems.
A clean result means the input passed the rules implemented by this utility. It does not guarantee application security, protocol interoperability or correct business behavior. Test important integrations against the exact MCP client, SDK, gateway and server versions used in your deployment.