How do I install the Fable Haiku skill?

Run npx skillmds@latest add mrtooher/fable-haiku in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Fable Haiku safe to use?

This skill has not completed SkillMD's automated safety review yet. Independent scanners report: SkillSpector: PASS, Skill Scanner: PASS. Capability flags: docs only. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Fable Haiku?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Fable Haiku free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Fable Haiku?

mrtooher (@mrtooher) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Fable Haiku by mrtooher — Agent Skill

Name: Fable Haiku
Rating: 4.2 (5 reviews)
Author: mrtooher

Fable Haiku

Run fable-mode execution discipline on Claude Haiku. Routes the task to the @fable-worker-haiku agent, whose definition carries the staged loop with tightened verification (no bare "unverified" allowed) and an escalate-don't-improvise rule. Trigger when the user explicitly asks for thorough/systematic handling run cheaply or fast ("fable on haiku", "deep work mode but cheap", "stage this on haiku"). For bulk mechanical work. Do NOT use for tasks needing synthesis — benchmark note: at n=1 the skill's effect on Haiku swung both directions (+25 / −17); route quality-critical work to fable-sonnet instead.

mrtooher Updated Sep 10, 2026

File contents

Fable Mode — Haiku (v3, agent-routed)

v3 change: the worker is a real agent definition (agents/fable-worker-haiku.md) invoked by name. Its system prompt carries the loop, the tightened verification rule, 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

Confirm fable-worker-haiku appears in the available agent types. If not, fall back to inline: spawn a general-purpose Haiku agent and pass it the rules verbatim from agents/fable-worker-haiku.md.
Spawn @fable-worker-haiku via the Task tool (subagent_type: "fable-worker-haiku"). Brief it with: the task, the exact output path(s), and the pass condition — name the check explicitly; Haiku gets no benefit of the doubt on verification.
Haiku is cheap: for independent sub-parts, fan out one worker per part and merge. Set a ceiling on concurrent workers.
Follow with @fable-verifier (a second Haiku is cheap; fresh eyes can't inherit the worker's blind spots) for anything that will be delivered without human review.
If a worker escalates ("needs synthesis"), re-route that part to fable-worker-sonnet rather than retrying Haiku with a louder prompt.
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.

---name: fable-haikudescription: Run fable-mode execution discipline on Claude Haiku. Routes the task to the @fable-worker-haiku agent, whose definition carries the staged loop with tightened verification (no bare "unverified" allowed) and an escalate-don't-improvise rule. Trigger when the user explicitly asks for thorough/systematic handling run cheaply or fast ("fable on haiku", "deep work mode but cheap", "stage this on haiku"). For bulk mechanical work. Do NOT use for tasks needing synthesis — benchmark note: at n=1 the skill's effect on Haiku swung both directions (+25 / −17); route quality-critical work to fable-sonnet instead.---# Fable Mode — Haiku (v3, agent-routed)v3 change: the worker is a real agent definition (`agents/fable-worker-haiku.md`)invoked by name. Its system prompt carries the loop, the tightened verificationrule, and the operational rules; this skill only routes.If a task has one obvious correct approach and fits in a single pass, skip thisloop and do it directly.## How to run it1. Confirm `fable-worker-haiku` appears in the available agent types. If not, fall back to inline: spawn a general-purpose Haiku agent and pass it the rules verbatim from `agents/fable-worker-haiku.md`.2. Spawn **@fable-worker-haiku** via the Task tool (`subagent_type: "fable-worker-haiku"`). Brief it with: the task, the exact output path(s), and the pass condition — name the check explicitly; Haiku gets no benefit of the doubt on verification.3. Haiku is cheap: for independent sub-parts, fan out one worker per part and merge. Set a ceiling on concurrent workers.4. Follow with **@fable-verifier** (a second Haiku is cheap; fresh eyes can't inherit the worker's blind spots) for anything that will be delivered without human review.5. If a worker escalates ("needs synthesis"), re-route that part to fable-worker-sonnet rather than retrying Haiku with a louder prompt.6. **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.

Frequently asked questions