feat(acp): register Zeph in the ACP Registry

[bug-ops]

Context

JetBrains and Zed jointly maintain the ACP Registry (launched 2026-01). Claude Code, Gemini CLI, and Codex are already listed. Zeph is not registered.

Hard gate for registry inclusion:

• The agent's initialize response MUST include authMethods with at least one entry (e.g., { type: "agent" } or { type: "terminal" }).
• Zeph currently returns authMethods: [] → registry CI rejects the submission.

What is needed

1. agent.json discovery manifest

{
  "id": "zeph",
  "name": "Zeph",
  "version": "0.18.0",
  "description": "Lightweight Rust AI agent with hybrid inference, semantic memory, and multi-channel I/O",
  "distribution": {
    "type": "binary",
    "platforms": ["linux-x64", "darwin-arm64", "darwin-x64"]
  }
}

Served at <agent-base-url>/agent.json (or via discovery endpoint in zeph-acp).

2. Non-empty authMethods in initialize response

At minimum: authMethods: [{ type: "agent" }]. This is the hard gate that currently blocks registry inclusion.

The actual auth flow implementation can be deferred (P3), but the field must be present and non-empty.

3. PR against ACP Registry repo

Submit zeph.json entry to the official registry (JetBrains/Zed joint repo).

Acceptance criteria

• initialize response includes authMethods: [{ type: "agent" }] (or "terminal")
• agent.json served at the ACP discovery endpoint
• PR opened against ACP Registry with Zeph entry

Related

• feat(acp): update agent-client-protocol 0.10.2→0.10.3 + schema 0.11.2→0.11.4 — logout, elicitation, NES, stabilized session/list #2411 — ACP crate update (prerequisite for schema-compliant response)
• feat(acp): implement session/close handler and capability advertisement #2421 — session/close handler (capability advertisement also needed for registry)

[bug-ops]

Detailed agent.json Schema Requirements (from ACP Registry CONTRIBUTING.md)

Registry CI validates agent.json against agent.schema.json. All fields below are required unless noted.

Required fields

Field	Type	Constraint
id	string	Pattern ^[a-z][a-z0-9-]*$ (lowercase, hyphens only)
name	string	Display name
version	string	Semver x.y.z
description	string	Non-empty
distribution	object	At least one of: binary, npx, uvx

Distribution for binary agents

"distribution": {
  "binary": {
    "targets": {
      "linux-x64": "https://github.com/bug-ops/zeph/releases/download/vX.Y.Z/zeph-linux-x64.tar.gz",
      "darwin-arm64": "https://github.com/bug-ops/zeph/releases/download/vX.Y.Z/zeph-darwin-arm64.tar.gz",
      "darwin-x64": "https://github.com/bug-ops/zeph/releases/download/vX.Y.Z/zeph-darwin-x64.tar.gz"
    }
  }
}

Optional fields

• repository — GitHub URL
• website — project URL
• authors — array of { name, email? }
• license — SPDX identifier (e.g. "MIT")
• icon — auto-derived from icon.svg; must be 16×16 SVG, monochrome, only currentColor

Registry hard gate (confirmed)

Registry CI checks that the agent's initialize response includes authMethods with at least one entry where type is "agent" or "terminal". This is verified programmatically — an authMethods: [] array will fail the check.

Minimum compliant initialize response fragment:

{
  "authMethods": [{ "type": "agent" }]
}

The actual logout flow can be stubbed (no-op) initially, as long as the field is non-empty.

Discovery endpoint

https://cdn.agentclientprotocol.com/registry/v1/latest/registry.json

Clients (Zed, JetBrains) fetch this for programmatic agent installation. Submission via PR to agentclientprotocol/registry.

[bug-ops]

Post-PR-#2423 status (CI-289 verification, 2026-03-30)

ACP initialize response after #2423:

{
  "protocolVersion": 1,
  "authMethods": [],
  "agentCapabilities": {
    "auth": { "logout": {} },
    ...
  }
}

Findings

• agentCapabilities.auth.logout: {} is now advertised ✅ (added by feat(acp): update agent-client-protocol 0.10.2→0.10.3, schema 0.11.2→0.11.3 #2423)
• protocolVersion: 1 ✅ (integer, fix(acp): discovery endpoint hardcodes "protocol_version": "0.9" — should reflect actual ProtocolVersion::LATEST #2412 fixed)
• authMethods: [] is still empty — registry gate still blocked

Root cause

authMethods is a top-level field in the initialize response (a list of AuthMethod objects the agent supports — e.g., [{ "type": "agent" }]). It is distinct from agentCapabilities.auth.logout, which advertises the logout capability.

PR #2423 correctly added the auth.logout capability advertisement but did not populate authMethods. These are two separate things:

• authMethods: [{ "type": "agent" }] — tells the client how to authenticate
• agentCapabilities.auth.logout: {} — tells the client the agent supports the logout method

What still needs to be done

Populate authMethods in the initialize response builder (in zeph-acp) with at least one entry:

auth_methods: vec![AuthMethod { type_: AuthMethodType::Agent, /* fields */ }],

The agent type means "authenticate via the agent's own auth flow". This doesn't require implementing a real auth handshake — the field just needs to be non-empty for registry CI to pass.