Runtime Protobuf-style field-contract validation for MCP tool/call arguments. Define a schema once; validate at every call boundary. Per-field typed errors (required, type mismatch, enum, bounds, format) — zero regex injection surface.
Test scenarios
This runs /kernel/flowdesk-mcp-schema.js entirely in your browser. No request leaves this page. The same validator runs server-side at /api/v1/agent/validate and returns a signed attestation bound to the SHA-256 of the (args, schema) pair.
Supported: type, required, enum, nullable, minLength/maxLength, format (date-iso8601|email|uri|uuid), minimum/maximum, minItems/maxItems, items, additionalProperties, nested objects (depth ≤ 8).
Not full JSON Schema — $ref, oneOf, if/then are not processed.