MACP Agent Manifest Schema Guide

Status: Non-normative (explanatory). In case of conflict, the referenced RFC is authoritative. Reference: RFC-MACP-0005

This schema gives MACP discovery a concrete, machine-readable contract.

Why it matters:

A discovery RFC explains what a manifest means.
A JSON Schema explains exactly what shape a valid manifest must have.

That makes discovery easier to implement, easier to validate, and much more credible as a protocol ecosystem.

Recommended placement

Put this file at:

schemas/json/macp-agent-manifest.schema.json

And reference it from:

• RFC-MACP-0005 Discovery & Manifests
• docs/discovery.md
• manifest examples in examples/

Core design choices

The schema requires only the fields needed for practical interoperability:

• agent_id — unique agent identifier
• description — human-readable description
• supported_modes — at least one coordination mode
• input_content_types — accepted content types
• output_content_types — produced content types

Optional fields:

• title — human-readable display name
• metadata — arbitrary string key-value pairs
• transport_endpoints — array of transport endpoint objects, each containing a registered transport identifier, URI, and supported content types (see $defs/TransportEndpoint in the schema)

This keeps the manifest lightweight while still being implementation-ready.

Content type fields (input_content_types, output_content_types, and transport_endpoints[*].content_types) SHOULD use registered MACP media types such as application/macp-envelope+proto and application/macp-envelope+json.

Example publishing pattern

A runtime or agent should publish a manifest at:

https://<host>/.well-known/macp.json

That document may include:

• supported MACP version
• transport endpoints
• supported modes
• auth expectations
• operational limits

Validation

Any implementation can validate a manifest against this schema before accepting it into a registry or using it for negotiation.

This is the piece that turns discovery from “a nice doc” into “a real interoperable surface.”