Compare the expected authorization server issuer with the OAuth authorization response iss value and stored credential issuer.
MCP 2026-07-28 requires stronger issuer validation. Clients should verify the authorization response issuer before redeeming a code and should not reuse client credentials across different authorization-server issuers.
Validate OAuth authorization response issuer values and detect issuer or credential-binding mismatches in MCP.
Use MCP OAuth Issuer Validator 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.
Authorization metadata must be treated as security-sensitive configuration. Static validation can reveal obvious inconsistencies, but a production OAuth deployment must also validate live issuer, redirect, token and authorization behavior at runtime.
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.
MCP Protected Resource Metadata Validator