fableplan

fableplan is a skill for Claude Code, Codex from richkuo/rk-skills. It costs 109 tokens per session (1,613 once invoked), scanned A, original, MIT.

A planning workflow that sends a coding task to a Fable 5 planning subagent and returns an implementation plan. If the task names a GitHub issue, the plan is also posted as a comment on that issue.

In plain words
What is it for?
Use it to plan a task or GitHub issue, inspect the relevant requirements, produce an implementation plan, and optionally ask whether to continue with the build.
Why use it?
It provides a written sequence of implementation steps before coding starts. This helps turn an unclear request or issue into concrete work that the main agent can follow.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions CLAUDE.md; mentions subagents; names the AskUserQuestion tool.

Part of the rk-skills plugin — 37 skills, 1 command shipped together

Good fit Use it to plan a task or GitHub issue, inspect the relevant requirements, produce an implementation plan, and optionally ask whether to continue with the build.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/richkuo/rk-skills/fableplan
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.

Any agent
npx skills add richkuo/rk-skills --skill fableplan
Clone the repo
git clone --depth 1 https://github.com/richkuo/rk-skills

Made for: Claude Code, Codex.

Or install rk-skills, the plugin that ships this one along with the rest of its 37 skills, 1 command.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for fableplan

README.md
[![agentmods](https://agentmods.dev/badge/skills/richkuo/rk-skills/fableplan/github.svg)](https://agentmods.dev/skills/richkuo/rk-skills/fableplan)
Your own site
<a href="https://agentmods.dev/skills/richkuo/rk-skills/fableplan"><img src="https://agentmods.dev/badge/skills/richkuo/rk-skills/fableplan/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for fableplan

Your own site · 80×15
<a href="https://agentmods.dev/skills/richkuo/rk-skills/fableplan"><img src="https://agentmods.dev/badge/skills/richkuo/rk-skills/fableplan.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 109 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,613 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00109 $0.01613
Opus 5 $0.00055 $0.00807
Sonnet 5 $0.00022 $0.00323
Haiku 4.5 $0.00011 $0.00161

Measured 2d ago against content hash 484d382254bb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

fableplan 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.

skills/fableplan/SKILL.md · 74 lines

How it starts

The opening of the file, as written. The whole thing — 74 lines — stays where its author put it; the contents beside it link to each section on GitHub.

fableplan

A Fable 5.1 Plan subagent writes the plan. The main agent checks it, posts it, and builds from it. The subagent never builds.

Input

A task description, with an optional issue reference (URL, #<N>, bare <N>, or owner/repo#N). With an issue, the plan is also posted as a comment. Ask what to plan only when the task is unclear. With no issue, never invent one or post anywhere.

Steps

1. Resolve the GitHub issue (only if one is referenced)

gh issue view <N> --json number,title,body,url (add -R owner/repo for another repository). Stop and tell the user if it fails; never plan from a paraphrase of an issue you could not fetch. Record the number and URL for step 4. Read any Plan effort line in the body's ## Execution block: planning runs at that tier when present, else high; a stamped xhigh runs at xhigh.

2. Dispatch the Fable 5.1 Plan subagent

Do not plan the task yourself first. Load the fable-dispatch skill before dispatching. It owns the ladder, the CLI shim (--effort <tier> carries the tier there), result parsing, attribution (section 6), and the hygiene rules every caller follows (section 7). On the Agent-tool path, call the Agent tool with:

  • subagent_type: Plan; model: fable; run_in_background: false; description: Plan <short task name>.
  • effort: the step 1 tier, passed explicitly when the Agent tool's schema exposes an effort property. When it does not, dispatch without it; when the check is inconclusive and the call fails input validation on that parameter, re-dispatch once without it. A dispatch without effort is a degradation to report in step 5, never a step failure.
  • prompt: everything needed to plan alone: the full task, the issue title and body when fetched, the working directory, and the user's constraints. Instruct it to:
    • Produce a concrete, ordered plan: files to create or modify, approach, build sequence, risks and edge cases, verification.
    • Number the implementation steps (1., 2., ...) and end each with a verify point: the observable check that proves the step is done (a command, a passing test, a file state). Builders mirror these steps into their task tracker.
    • Plan the absolute-best solution; only correctness and safety override "best".
    • Return the plan as its final message in clean Markdown, fit to post verbatim as an issue comment.
    • Make no file edits and no commits, including through Bash (fable-dispatch section 7).

Read the full file on GitHub · 74 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 Changed · -28 lines 484d382254bb
  2. 3d ago Changed 9dbad120724f
  3. 5d ago Changed · -12 lines · +4 tokens per session 6bdfdace8a4a
  4. 9d ago First seen · 114 lines · 105 tokens per session scan A d6d2e82da657

Subscribe to this mod's changes

fableplan is a skill published in the GitHub repository richkuo/rk-skills (49 stars, last pushed today), licensed MIT. It adds 109 tokens to every session and 1,613 once invoked, about $0.0005 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 2026-08-30.