mrtooher/fable-mode

fable-sonnet

Run fable-mode execution discipline on Claude Sonnet. Routes the task to the @fable-worker-sonnet agent, whose definition carries the staged loop with step-3 verification enforced hardest (Sonnet's known gap), optionally followed by a cold @fable-verifier pass. Trigger when the user explicitly asks for thorough/systematic/"deep work" handling on Sonnet ("fable on sonnet", "stage this on sonnet", "deep work mode, sonnet"). The balanced default between Haiku (cheap/fast) and Opus/Fable (peak reas…

First seen Jun 23, 2026

Installation

$ npx skills add mrtooher/fable-mode --skill fable-sonnet

Also in this package

Other skills from mrtooher/fable-mode.

npx skills add mrtooher/fable-mode

Browse all from mrtooher/fable-mode

More details

Agent compatibility

Declared targets from SKILL.md / docs. Unmarked agents are not listed — the skill may still install via the CLI.

Claude Code Not declared
Cursor Not declared
Codex Not declared
GitHub Copilot Not declared
Windsurf Not declared
Gemini CLI Not declared
Cline Not declared
OpenCode Not declared

Repository health

Stars 854
Default branch main
Open issues 0
Status Active

Package contents

Files included with this skill beyond the listing page.

  • skill md SKILL.md 2,130 B
  • docs SUMMARY.md 569 B

History

  1. First seen on skills.sh
  2. First recorded snapshot · 4 installs

SKILL.md

Fable Mode — Sonnet (v3, agent-routed)

v3 change: the worker is a real agent definition (agents/fable-worker-sonnet.md) invoked by name, not a prose briefing the model can soft-ignore. Its system prompt carries the loop and the operational rules; this skill only routes.

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

  1. Confirm fable-worker-sonnet appears in the available agent types. If not,

fall back to inline: spawn a general-purpose Sonnet agent and pass it the rules verbatim from agents/fable-worker-sonnet.md.

  1. Spawn @fable-worker-sonnet via the Task tool (`subagent_type:

"fable-worker-sonnet"`). Brief it with: the task, the exact output path(s), relevant context, and the pass condition its deliverable must satisfy — name the check, don't leave it to taste.

  1. For independent sub-parts, spawn multiple workers concurrently and merge.

Cap concurrency at a handful. Workers do not spawn workers.

  1. For high-stakes deliverables, follow with @fable-verifier, briefed with

only the spec and the artifact path — not the worker's report.

  1. Relay results and anything marked unverified.
  2. Mandatory delivery gate: before presenting the result to the user, invoke

the double-check skill on the finished deliverable. If step 4's verifier already cold-checked the final document, double-check runs only the seam check — its own rules handle that. Do not skip the gate.