MSP-1 Specification

protocol

The protocol term declares the identity and version of the MSP-1 implementation in use. It provides AI agents and validators with a deterministic way to understand compatibility, expected behavior, and supported semantic structures.

Category: Content structure, intent & addressing

Status: Normative

Version: MSP-1.0.x

1. Purpose

The protocol term ensures that AI agents can correctly interpret metadata, validate structures, and understand the ruleset governing the site. It allows systems to:

Confirm whether MSP-1 is implemented.
Determine which version(s) of the protocol apply.
Adjust interpretation or validation logic accordingly.
Resolve compatibility questions as the protocol evolves.

2. Normative definition

A protocol declaration identifies the MSP-1 specification being used by a site or resource. It MUST include:

protocol — the literal string "MSP-1".
version — a specific version identifier (e.g., "1.0.0").

A protocol declaration MAY also include the version range the resource supports (e.g., "MSP-1.0.x"), particularly at the site level.

3. Required fields

protocol — MUST equal "MSP-1".
version — MUST be a valid semantic version.

Recommended fields include:

supportedVersionRange — defines compatible versions for agents.
defaultVerificationTarget — the recommended trust or review mode.
policies — optional settings that define enforcement or validation behavior.

4. AI interpretation rules

AI agents MUST treat protocol as the authoritative signal that MSP-1 metadata is present and should be interpreted using the specified version rules.
If version mismatches occur, agents SHOULD degrade gracefully and revert to the nearest supported version range.
Missing protocol declarations SHOULD cause agents to treat metadata as non-normative, reducing trust and validation strictness.
Multiple conflicting protocol declarations MUST be treated as an error state.

Protocol declarations allow future MSP versions to evolve without breaking existing implementations.

5. Relationship to related MSP-1 terms

version — describes the specific version of a resource; protocol governs the site-wide rule set.
revision — defines changes within a resource; separate from protocol versioning.
compliance — protocol declarations determine what compliance levels mean.
authority — helps identify authoritative protocol sources.
site — the protocol applies at the site level unless overridden.

6. Examples

Minimal example:

{
  "protocol": "MSP-1",
  "version": "1.0.0"
}

Site-level protocol declaration with version range and policies:

{
  "protocol": "MSP-1",
  "version": "1.0.0",
  "supportedVersionRange": "MSP-1.0.x",
  "defaultVerificationTarget": "authoritative",
  "policies": {
    "review": {
      "required": true,
      "frequency": "per-revision"
    }
  }
}

Example showing forward compatibility strategy:

{
  "protocol": "MSP-1",
  "version": "1.0.0",
  "supportedVersionRange": "MSP-1.0.x",
  "policies": {
    "fallback": "interpret-closest-version"
  }
}

7. Conformance

A resource conforms to the MSP-1 protocol specification when:

It correctly declares protocol: "MSP-1".
It provides a valid, stable semantic version identifier.
Additional fields (if included) follow the normative rules above.
It avoids contradictory protocol declarations within the same resource.