Interceptors

Enable extensions.interceptors, then register handlers with .mcpInterceptor(definition, handler). Clients discover them with interceptors/list and invoke one with singular interceptor/invoke. The experimental source has used both plural and singular invocation names; this adapter implements the canonical singular method only.

executeInterceptorChain() provides local execution without an external interceptor service. Pass the explicit sending direction to mutate before validation. Pass receiving to validate before mutation. The request or response phase selects a phase-specific priorityHint. Mutators run sequentially and atomically by ascending priority, with name order breaking ties.

Validators run in parallel against separate structured clones, so one validator cannot change another validator's payload. Mutator output is also cloned before it becomes the next chain input. A validation result blocks only when valid is false and severity is error; info, warn, and omitted severity remain observable without blocking.

Audit handlers shadow their result and never block. The returned audit outcomes report the interceptor, completed or failed status, severity, result, or error. Active failures close by default. Set failOpen only for a deliberate availability policy; its failure also appears as a warning audit outcome. timeoutMs aborts the handler signal and returns a protocol error. Hook overrides can narrow a registration but cannot broaden it.

Handlers may omit result identity fields. The adapter supplies and validates the required interceptor, type, and phase fields on every wire result. A handler cannot claim another identity, type, or phase.

The adapter does not discover or contact external interceptor services. Keep secrets and model-controlled credentials outside interceptor configuration.