writing-skills

writing-skills is a skill for Claude Code from andreymudri/claude-teammates. It costs 21 tokens per session (1,561 once invoked), scanned A, original, MIT.

A guide for creating and checking reusable instructions called skills, using test-driven development (TDD), where tests are written or observed before and after the instructions are added.

In plain words
What is it for?
Use it to create new skills, edit existing ones, start from the provided template, and run the skill checks before deployment.
Why use it?
It helps verify that a skill changes agent behavior in the intended way and meets the project's required structure.

Skill for Claude Code

Written for Claude Code: $CLAUDE_PLUGIN_ROOT variable. Also seen: mentions subagents.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the claude-teammates plugin — 14 skills, 3 agents, 2 hooks shipped together

Good fit Use it to create new skills, edit existing ones, start from the provided template, and run the skill checks before deployment.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add andreymudri/claude-teammates
Claude Code
/plugin install claude-teammates

Made for: Claude Code.

Or install claude-teammates, the plugin that ships this one along with the rest of its 14 skills, 3 agents, 2 hooks.

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 writing-skills

README.md
[![agentmods](https://agentmods.dev/badge/skills/andreymudri/claude-teammates/writing-skills/github.svg)](https://agentmods.dev/skills/andreymudri/claude-teammates/writing-skills)
Your own site
<a href="https://agentmods.dev/skills/andreymudri/claude-teammates/writing-skills"><img src="https://agentmods.dev/badge/skills/andreymudri/claude-teammates/writing-skills/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 writing-skills

Your own site · 80×15
<a href="https://agentmods.dev/skills/andreymudri/claude-teammates/writing-skills"><img src="https://agentmods.dev/badge/skills/andreymudri/claude-teammates/writing-skills.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 21 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,561 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.
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 $0.00021 $0.01561
Opus 5 $0.00010 $0.00781
Sonnet 5 $0.00004 $0.00312
Haiku 4.5 $0.00002 $0.00156

Measured 12d ago against content hash e91f8f56cfed, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

writing-skills 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 12d 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/writing-skills/SKILL.md · 127 lines

How it starts

The opening of the file, as written. The whole thing — 127 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Writing Skills

Adapted from the MIT-licensed superpowers plugin by Jesse Vincent. See NOTICE.md.

Overview

Writing a skill is Test-Driven Development applied to process documentation. Watch an agent fail without the skill (baseline), write the skill, then watch a fresh agent comply. If you never watched the failure, you don't know whether the skill teaches the right thing — or whether there was anything to teach at all.

A skill is a reusable technique, pattern, or reference — not a narrative about how you solved something once. Don't create one for a one-off fix or a project-specific convention (put that in the project's own instructions file instead).

Start from the template

Copy templates/SKILL.template.md as the starting structure for a new skill. It carries the required frontmatter shape and the section skeleton (When to use / Process / Red flags) — fill it in rather than improvising frontmatter from scratch.

Rules this plugin's test suite enforces

These are checked mechanically by tests/skills.test.mjs and tests/skill-contracts.test.mjs on every skill under skills/ — get them wrong and the suite fails, not just a reviewer:

  • name matches the containing folder exactly. skills/writing-skills/SKILL.md must declare name: writing-skills.
  • description starts with Use when. It states triggering conditions, not what the skill does — see "Write the description as a trigger" below.
  • Every CLI subcommand named in the body must actually exist. Only init-run, gate, digest, claim, unclaim, and workflow are real subcommands of the CLI entrypoint. Naming a subcommand that doesn't exist fails the suite, not just the reader.
  • Every tm-* agent named in the body must actually exist. Only tm-implementer, tm-reviewer, and tm-integrator exist under agents/.
  • The CLI is always invoked through $CLAUDE_PLUGIN_ROOT, never a relative path: node "$CLAUDE_PLUGIN_ROOT/scripts/cli.mjs" <subcommand> --root <project root>. A relative invocation works from the author's shell and breaks for everyone else.

Read the full file on GitHub · 127 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. 12d ago First seen · 127 lines · 21 tokens per session scan A e91f8f56cfed

Subscribe to this mod's changes

writing-skills is a skill published in the GitHub repository andreymudri/claude-teammates (2 stars, last pushed 10d ago), licensed MIT. It adds 21 tokens to every session and 1,561 once invoked, about $0.0001 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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