mTLS

Mutual TLS (mTLS) extends TLS with client certificate authentication: AI Gateway verifies the connecting agent's certificate, in addition to the agent verifying AI Gateway's certificate. This suits deployments where every calling agent or service is provisioned with its own client certificate, instead of, or in addition to, an OAuth guard flow.

Requiring Client Certificates

Add a trust store containing the certificate authority for agent certificates to the same filesystem vault used for AI Gateway's own key, then reference the trusted certificate alias from the tls server binding and set options.mutual to required:

vaults:
  server_vault:
    type: filesystem
    options:
      keys:
        store: ${{env.KEYSTORE_PATH}}
        type: ${{env.KEYSTORE_TYPE}}
        password: ${{env.KEYSTORE_PASSWORD}}
      trust:
        store: ${{env.TRUSTORE_PATH}}
        type: ${{env.TRUSTORE_TYPE}}
        password: ${{env.TRUSTORE_PASSWORD}}

bindings:
  north_tcp_server:
    type: tcp
    kind: server
    options:
      host: 0.0.0.0
      port: 8443
    exit: north_tls_server

  north_tls_server:
    type: tls
    kind: server
    vault: server_vault
    options:
      keys:
        - ${{env.SERVER_CERT_ALIAS}}
      trust:
        - ${{env.CA_CERT_ALIAS}}
      sni:
        - ${{env.SERVER_HOSTNAME}}
      mutual: required
    exit: north_http_server

  north_http_server:
    type: http
    kind: server
    options:
      access-control:
        policy: cross-origin
    routes:
      - when:
          - headers:
              ":path": /mcp
        exit: north_mcp_server

  north_mcp_server:
    type: mcp
    kind: server
    exit: north_mcp_proxy

With mutual: required, AI Gateway rejects the TLS handshake for any agent that does not present a certificate signed by a trusted authority, before the connection reaches the http server or mcp server bindings.

See the tls server binding reference for the full set of options fields, including options.mutual.