Protocol Profiles

A2A Mesh conformance now uses explicit compatibility profiles instead of treating every fixture as the same protocol contract. The profile artifact lives in packages/runtime/src/testing/profiles.ts and is included in every conformance JSON report as profile plus a row-level coverage matrix.

Profiles

Profile	Strict	Protocol	Purpose
official-a2a-v1.0	Yes	1.0	The default strict profile aligned to the normative A2A v1.0 protobuf and HTTP+JSON binding surface.
legacy-a2amesh	No	1.0	Backwards-compatible behavior for existing A2A Mesh JSON-RPC paths, local aliases, and push notification method names.
experimental-a2a-v1.2	No	1.2	Opt-in fixtures for future A2A Mesh behavior. Requires --experimental-profiles.

Status vocabulary

Status	Meaning
supported	Implemented and exercised by the current profile fixture surface.
partial	Implemented in part, but the strict profile records an explicit gap or follow-up.
legacy-alias	Supported for A2A Mesh compatibility, but not the canonical official v1.0 surface.
unsupported	Not implemented yet; the coverage row must name the issue that tracks it.

The official strict profile intentionally reports known gaps. For example, HTTP+JSON REST binding is marked unsupported and tracked by #316, while returnImmediately, historyLength, official task state compatibility, and push notification config naming are tracked by #315. This prevents local conformance from silently passing only A2A Mesh-specific behavior.

Running the strict profile

a2amesh conformance http://127.0.0.1:3000 --profile official-a2a-v1.0 --strict --json

The equivalent programmatic API is:

const report = await runConformanceSuite({
  client,
  endpointUrl: 'http://127.0.0.1:3000',
  packageVersion: '11.0.0',
  profile: 'official-a2a-v1.0',
  strict: true,
});

Report fields

Strict profile reports include these additional fields:

{
  "profile": {
    "id": "official-a2a-v1.0",
    "strict": true,
    "protocolVersion": "1.0",
    "coverage": {
      "supported": 1,
      "partial": 6,
      "legacyAlias": 1,
      "unsupported": 1,
      "requiredUnsupported": 1
    }
  },
  "coverage": [
    {
      "id": "binding.http-json-rest",
      "status": "unsupported",
      "required": true,
      "trackedBy": "#316"
    }
  ]
}

The coverage rows are designed for dashboards such as #300. They can be rendered as a visual compliance report without re-encoding profile rules in the UI.

Relationship to protocol versions

--protocol-version 1.0 maps to official-a2a-v1.0 by default. --strict also resolves to official-a2a-v1.0 when no --profile is provided.

--protocol-version 1.2 maps to experimental-a2a-v1.2 and requires --experimental-profiles. This keeps experimental fixtures opt-in and separate from the official strict profile.

Legacy profile

Use the legacy profile only when validating compatibility with existing A2A Mesh clients or servers:

a2amesh conformance http://127.0.0.1:3000 --profile legacy-a2amesh --json

Legacy rows are still visible as legacy-alias so downstream reports can distinguish backwards compatibility from official protocol support.