fable-mode

A coding workflow that makes an agent plan from a specification, record progress, delegate suitable tasks, and verify its work. It supports lite, full, and ultra levels of checking.

In plain words
What is it for?
Use it to structure implementation work, maintain file-based notes, coordinate parallel helpers, and check that the finished result meets the stated requirements.
Why use it?
It gives coding tasks a repeatable process for clarifying success conditions and supporting claims with evidence.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/ayborg43/fable-mode/fable-mode
Any agent
npx skills add ayborg43/fable-mode --skill fable-mode
Clone the repo
git clone --depth 1 https://github.com/ayborg43/fable-mode

Made for: Claude Code, Codex.

Per session 191 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,418 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00191 $0.03418
Opus 5 $0.00096 $0.01709
Sonnet 5 $0.00038 $0.00684
Haiku 4.5 $0.00019 $0.00342

Measured 2d ago against content hash 6b06351f144e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

fable-mode scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

SKILL.md · 144 lines

How it starts

The opening of the file, as written. The whole thing — 144 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Fable Mode

This skill encodes the working discipline of Claude Fable 5 — Anthropic's most capable coding model — so that any model can apply the same process. Be honest with yourself about what this is: a skill cannot add raw intelligence, but most of what makes Fable 5's coding output trustworthy is process, not IQ — it specifies before it builds, verifies as it goes, delegates in parallel, writes down what it learns, and never claims progress it can't point to evidence for. All of that is executable by any capable model. Follow it exactly.

Invocation

  • Invoked with a task (/fable-mode <task>, or triggered by a rigor request): apply this process to that task immediately — the argument text is the task.
  • Invoked bare (/fable-mode with no task): confirm fable mode is active in one sentence and await the task. Do not invent one.
  • Intensity levels — an optional first argument (/fable-mode lite <task>, /fable-mode ultra <task>):
    • lite — for small, scoped tasks. Keep the spec, scope discipline, and evidence rules; skip the formal harness, the memory file, and delegation.
    • full (default) — everything in this document.
    • ultrafull, plus a mandatory fresh-context verifier sub-agent pass and a minimum of three consecutive clean harness runs (not one) before any completion claim — more when the failure mode is intermittent.
    • If no level was given and the task is obviously small (one file, one clear change, verifiable in a single command), apply lite yourself and say so in half a sentence — do not run a small task through the full ceremony.
  • Loop flagloop before the task, combinable with a level (/fable-mode loop <task>, /fable-mode ultra loop <task>): the run is recurring, scheduled, or resumable across sessions — apply Phase 2.5. Also apply Phase 2.5 unprompted when you recognize the run is one of these (invoked by a recurring scheduler, resumed after a restart, expected to span wake-ups) and say so in half a sentence.

Read the full file on GitHub · 144 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 144 lines · 191 tokens per session scan A 6b06351f144e

Subscribe to this mod's changes

fable-mode is a skill published in the GitHub repository ayborg43/fable-mode (2 stars, last pushed 1mo ago), licensed MIT. It adds 191 tokens to every session and 3,418 once invoked, about $0.0010 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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