Borrowing it
Nothing to install: this file belongs to moberghr/mtk-agent-toolkit. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/moberghr/mtk-agent-toolkit/main/.claude/skills/writing-skills/SKILL.mdgit clone --depth 1 https://github.com/moberghr/mtk-agent-toolkitWrote 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/moberghr/mtk-agent-toolkit/writing-skills)<a href="https://agentmods.dev/skills/moberghr/mtk-agent-toolkit/writing-skills"><img src="https://agentmods.dev/badge/skills/moberghr/mtk-agent-toolkit/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.
<a href="https://agentmods.dev/skills/moberghr/mtk-agent-toolkit/writing-skills"><img src="https://agentmods.dev/badge/skills/moberghr/mtk-agent-toolkit/writing-skills.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 | $0.00035 | $0.01974 |
| Opus 5 | $0.00017 | $0.00987 |
| Sonnet 5 | $0.00007 | $0.00395 |
| Haiku 4.5 | $0.00003 | $0.00197 |
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 yesterday.
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.
How it starts
The opening of the file, as written. The whole thing — 162 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Writing Skills
Overview
A skill is a reusable behavior contract that shapes how an agent approaches a category of work. Writing a good skill requires observing baseline failures first, then writing the minimum documentation that closes those gaps, then testing that the skill resists pressure.
When To Use
- Adding a new skill to the toolkit
- Substantially rewriting an existing skill
- Converting a one-off command pattern into a reusable skill
When NOT To Use
- One-off project-specific conventions (put those in CLAUDE.md)
- Mechanical constraints better handled by automation (put those in hooks or settings)
- Well-documented standard practices that don't need reinforcement
Workflow
Phase 1: Observe Baseline Failures
Before writing any skill content:
- Run 2-3 representative scenarios without the skill.
- Document what went wrong:
- What steps were skipped?
- What rationalizations were used to skip them?
- What outcomes were produced?
- This creates the "RED" baseline — the specific gaps the skill must close.
Phase 2: Write The Minimum Skill
-
Follow the anatomy defined in
docs/skill-anatomy.md:- Required: frontmatter (
name,description,type: skill— ortype: tech-stackfor tech stack skills),# Title,## Overview,## When To Use,## Workflow,## Verification - Recommended:
### When NOT To Use,## Red Flags,## Rules - The shared MTK rationalization table lives in
.claude/skills/context-engineering/SKILL.md. Do not duplicate universal rationalizations here. Only add a short## Common Rationalizationssection if the skill has one or two traps that are genuinely specific (and reference the shared table at the top).
- Required: frontmatter (
-
Apply the CSO principle: The
descriptionin frontmatter must trigger on conditions, not summarize the workflow.- Bad: "Create implementation plans with acceptance criteria and dependency ordering"
- Good: "Use after a spec is approved and before multi-file implementation begins"
- Why: Workflow summaries cause the agent to follow the description instead of reading the full SKILL.md
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.
- yesterday Changed c2a99e0f7c6b
- 10d ago First seen · 162 lines · 35 tokens per session scan A 04f158fb1555
writing-skills is a skill published in the GitHub repository moberghr/mtk-agent-toolkit (7 stars, last pushed yesterday), licensed MIT. It adds 35 tokens to every session and 1,974 once invoked, about $0.0002 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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