_protocol

Fellowship Agent Messaging Protocol

Canonical spec for how fellowship agents deliver reports and respond to lifecycle events via SendMessage.

Sync note: Agent definition files must be self-contained at runtime — an agent's markdown is injected as its system prompt with no path context, so an installed plugin's agents cannot reliably read sibling files (their working directory is the user's project, not the plugin cache). Skills are different: the Skill tool exposes the invoked skill's directory, which is why SKILL.md files can reference sibling resources/*.md while agents cannot. Each agent therefore embeds the parts of this protocol it needs inline. When you edit this spec, update the embedded copies in balrog.md, palantir.md, and scout.md.

Sending a Report

Use SendMessage to deliver findings or status to the requesting agent:

{
  "type": "message",
  "recipient": "<requester>",
  "content": "[markdown content]",
  "summary": "[short one-line summary for logs]"
}

• recipient: whoever requested the work, as provided at spawn time. SendMessage addresses agents by teammate name, not task ID.
  • Agents spawned by a teammate (e.g. balrog, spawned by a quest runner): the requester's teammate name from the spawn context (e.g. "quest-auth-bug").
  • Agents spawned by the fellowship lead (e.g. palantir): the lead — "team-lead".
  • If no requester name was provided (standalone mode), present output directly to the user instead of using SendMessage.
• content: full markdown report body.
• summary: one-line description shown in task logs (e.g., "balrog: 2 critical, 1 high, 0 medium, 3 low findings").

Shutdown

When you receive a shutdown request via SendMessage, respond immediately and stop:

{
  "type": "shutdown_response",
  "request_id": "<from the incoming message>",
  "approve": true
}

Do not perform any further work after sending a shutdown response.