fable-method AGENTS.md

Project instructions for the Fable Method, a structured way to classify coding requests, define completion, and gather evidence before acting.

In plain words
What is it for?
Use them when deciding how to approach a coding or documentation request, especially when the task is more than a small one-file change.
Why use it?
They reduce free-form decision-making and set checks for trivial tasks, research, scope, and implementation.

Instructions file for CodexOpenCode

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 instructions/ardhaecosystem/fable-method/agents-md
Clone the repo
git clone --depth 1 https://github.com/ardhaecosystem/fable-method

Made for: Codex, OpenCode.

Per session 1,942 This file is loaded in full into every session.
When invoked 1,942 The same file — it is already loaded in full.
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 $0.01942 $0.01942
Opus 5 $0.00971 $0.00971
Sonnet 5 $0.00388 $0.00388
Haiku 4.5 $0.00194 $0.00194

Measured 2d ago against content hash 999ca14b7fb2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

fable-method AGENTS.md 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.

AGENTS.md · 105 lines

How it starts

The opening of the file, as written. The whole thing — 105 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md - The Fable Method

Portable version for any agent harness (Codex, Cursor, aider, a raw system prompt). Drop this file at your repo root or paste it into your agent instructions.

A model that follows this loop beats a stronger model that free-styles. The quality lives in the structure, the evidence, and the honesty, not in the model. Follow it literally. The steps structure your work, never your output: do not narrate step numbers in anything the user reads.

Triviality gate (run first)

A task is trivial only if ALL of these are true: one file, under ~10 changed lines, no new behavior, and you already know exactly what to change without searching. If trivial: make the change, confirm with the one obvious check, report in two sentences. Everything else gets the full loop.

Fit gate (run next, before Step 0)

Locate where the answer lives, and route:

  • In sources you can open (a spec, file, dataset, docs): run the loop. Default.
  • In an established technique you do not yet know: research it first, then run the loop.
  • Only in your own inference: say so. Do not dress a guess as a rigorous process. Ask whether to proceed with a low-confidence answer, or label it as such.
  • In a specialized procedure that recurs: build it as a reusable skill.

Name any detour in the report. A silent detour is indistinguishable from a skipped step.

Step 0 - Classify the ask

Shape Signal Deliverable
Question / assessment "why is...", "what do you think..." Findings and a recommendation. Change nothing.
Task "fix", "build", "change", "make" The completed change, verified.
Plan-first ambiguous scope, irreversible actions, or plan requested A plan with your recommendation. Stop and wait.

Tie-breaks: plan-first beats task on any tie. A mixed ask is a task that must also answer the question. Unsure between task and plan-first: choose plan-first.

If only the user can settle ambiguous scope, ask exactly one pointed question with your recommended interpretation, then wait.

Read the full file on GitHub · 105 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 · 105 lines · 1,942 tokens per session scan A 999ca14b7fb2

Subscribe to this mod's changes

fable-method AGENTS.md is an instructions file published in the GitHub repository ardhaecosystem/fable-method (11 stars, last pushed 1mo ago), licensed MIT. It adds 1,942 tokens to every session, about $0.0097 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.