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.
npx skills add sutchan/Agent-Skills-Hub --skill writing-plansgit clone --depth 1 https://github.com/sutchan/Agent-Skills-HubWrote 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.
[](https://agentmods.dev/skills/sutchan/agent-skills-hub/writing-plans)<a href="https://agentmods.dev/skills/sutchan/agent-skills-hub/writing-plans"><img src="https://agentmods.dev/badge/skills/sutchan/agent-skills-hub/writing-plans/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.
<a href="https://agentmods.dev/skills/sutchan/agent-skills-hub/writing-plans"><img src="https://agentmods.dev/badge/skills/sutchan/agent-skills-hub/writing-plans.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00022 | $0.02362 |
| Opus 5.5 | $0.00009 | $0.00945 |
| Sonnet 5.5 | $0.00004 | $0.00472 |
| Haiku 4.5 | $0.00002 | $0.00236 |
Grade A, and why
writing-plans 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 10d 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.
This is a copy
86% identical to writing-plans — 76 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 209 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Writing Plans
Overview
Write implementation plans for an engineer who has not seen this codebase or this spec. Assume they write idiomatic code in the project's language once they know the exact interface and the exact test, and that they will make a reasonable choice wherever the plan leaves one open. What they cannot know is what you decided: which files, which names and signatures, which values from the spec, which tests prove each task. Document those. Give them the whole plan as bite-sized tasks. DRY. YAGNI. TDD. Frequent commits.
Announce at start: "I'm using the writing-plans skill to create the implementation plan."
Context: If working in an isolated worktree, it should have been created via the superpowers:using-git-worktrees skill at execution time.
Save plans to: docs/superpowers/plans/YYYY-MM-DD-<feature-name>.md
- (User preferences for plan location override this default)
Scope Check
If the spec covers multiple independent subsystems, it should have been broken into sub-project specs during brainstorming. If it wasn't, suggest breaking this into separate plans — one per subsystem. Each plan should produce working, testable software on its own.
File Structure
Before defining tasks, map out which files will be created or modified and what each one is responsible for. This is where decomposition decisions get locked in.
- Design units with clear boundaries and well-defined interfaces. Each file should have one clear responsibility.
- You reason best about code you can hold in context at once, and your edits are more reliable when files are focused. Prefer smaller, focused files over large ones that do too much.
- Files that change together should live together. Split by responsibility, not by technical layer.
- In existing codebases, follow established patterns. If the codebase uses large files, don't unilaterally restructure - but if a file you're modifying has grown unwieldy, including a split in the plan is reasonable.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 10d ago Changed · +13 lines 2d88665f766c
- 25d ago First seen · 196 lines · 22 tokens per session scan A 29640c4a41e7
writing-plans is a skill published in the GitHub repository sutchan/Agent-Skills-Hub (2 stars, last pushed 5d ago), licensed MIT. It adds 22 tokens to every session and 2,362 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 86% identical to writing-plans, differing in 76 lines, and is treated as a copy.
Other skills, from other repositories
test-driven-development
Use when implementing any feature or bugfix, before writing implementation code.
testing-patterns
Plan, write, and maintain automated tests in any language, with worked examples in Python and JavaScript/TypeScript. Use this skill whenever the user wants to write or plan tests, apply TDD (red-green-refactor), structure unit tests with arrange-act-assert and given-when-then naming, choose between fakes, stubs, and…
laravel-tdd
Drives Laravel feature development with Pest or PHPUnit — factories, RefreshDatabase, fakes for queues/mail/notifications, Sanctum auth, and Inertia assertions. Use when writing or fixing a Laravel controller, Eloquent model, policy, job, or notification, when the project uses Pest/PHPUnit, or when asked to test an…
php-codeigniter-tdd
Drives CodeIgniter 4 test development — CIUnitTestCase, DatabaseTestTrait's migrate/refresh/seed lifecycle, the dedicated tests database group, and FeatureTestTrait for HTTP-level assertions. Use when writing or fixing a CodeIgniter 4 test, when a test touches the database, or when a test suite is unexpectedly slow or…
test-driven-development
Drives development with tests written before implementation code, in Go, TypeScript, PHP, or any language. Use when implementing new logic or behavior, fixing a reported bug (write the reproduction test first), modifying existing functionality, or when asked to "add a test," "TDD this," or "prove this works." Use even…
test-driven
A test-driven development guide. TDD means writing a test for the desired behaviour first, seeing it fail, then writing the smallest implementation that makes it pass.