SKILL.md
Fable Mode — Opus (v3, agent-routed)
v3 change: delegation is enforced structurally, not requested in prose. The orchestrator is a real agent definition (agents/fable-orchestrator.md) with no Write/Edit tool — it cannot do the work inline, so "spawn a worker" stops being a suggestion the model can skip. (Change prompted by field report: prose-level "you may spawn workers" almost always ran inline on the main thread.)
If a task has one obvious correct approach and fits in a single pass, skip this loop and do it directly.
How to run it
- Confirm the fable agents are installed (
fable-orchestrator,
fable-worker-sonnet, fable-worker-haiku, fable-verifier appear in the available agent types). If they are not, fall back to the inline method: spawn a general-purpose Opus agent and pass it the Core Loop, domain patterns, and operational rules verbatim from the fable-mode skill, which is installed alongside this one. Do NOT try to read agents/fable-orchestrator.md — agent files exist only on surfaces that load an agents/ directory (Claude Code), never on skill-only surfaces (Cowork), which is exactly where this fallback fires.
- Spawn @fable-orchestrator via the Task tool (`subagent_type:
"fable-orchestrator"`). Brief it with: the user's task, the output directory, relevant session context, and any user-set limits (warning threshold, worker cap, deadline).
- Do not restate the Core Loop or operational rules in the briefing — the
orchestrator's agent definition carries them. Brief the task, not the method.
- When it returns, relay the result, every stage it marked unverified, and its
recommendations (surfaced scope it did not build). If it reports the task beyond Opus's capability, offer a fable-fable rerun (Fable 5.1) rather than retrying Opus.
- Mandatory delivery gate: before presenting the result to the user, invoke
the double-check skill on the finished deliverable. Pass it the orchestrator's closing FINAL-COLD-CHECK: line verbatim — yes means fable-verifier already checked the finished deliverable and double-check runs the seam check only; intermediates-only, no, or a missing line means the full panel runs. Do not skip the gate; the user relies on it instead of re-checking the work themselves.
Known limitation
Write-removal closes the front door, not the side door: the orchestrator keeps Bash for running verification commands, and Bash can technically create files. Its definition forbids that use; if audits show it writing through Bash, the next tightening is removing Bash and routing even check-execution through workers (cost: one extra hop per check).