agent.yaml reference

name: research_crew        # lowercase [a-z][a-z0-9_]*; becomes the schema/agent key
model: anthropic/claude-opus-5   # provider/model; mock/echo runs offline
maxTokens: 16000           # per model call (default 16000)
limits:
  maxStepsPerTask: 50      # hard cap on loop steps per task (default 50)

• Every field is optional except that the file must exist at the agent root (subagents/*/agent.yaml may omit anything — defaults apply).
• instructions.md beside it is the system prompt; missing → a generic default.
• Model routing is by prefix: mock/ (offline echo), anthropic/ (needs ANTHROPIC_API_KEY). Subagents may each use different models.

Planned keys (spec §9, not yet implemented — will fail silently today, don't set them): fallbacks, runtime: short|long, sandbox.image, sandbox.snapshotEvery, limits.maxWaves, limits.maxWallClockMin, limits.maxBudgetUsd.