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 agentmods add skills/alleneubank/claude-code/writing-skillsnpx skills add alleneubank/claude-code --skill writing-skillsgit clone --depth 1 https://github.com/alleneubank/claude-codeWrote 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/alleneubank/claude-code/writing-skills)<a href="https://agentmods.dev/skills/alleneubank/claude-code/writing-skills"><img src="https://agentmods.dev/badge/skills/alleneubank/claude-code/writing-skills.svg" alt="Measured on agentmods" 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 | $0.00028 | $0.00549 |
| Opus 5 | $0.00014 | $0.00275 |
| Sonnet 5 | $0.00006 | $0.00110 |
| Haiku 4.5 | $0.00003 | $0.00055 |
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 6d 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.
How it starts
The opening of the file, as written. The whole thing — 88 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Writing Skills
Overview
A skill should capture reusable judgment, not a story about one session.
Core principle: Write the minimum instructions that reliably change future agent behavior on the right class of tasks.
Directory Choice
Choose the source of truth before editing:
- Shared skill source: edit the repo-managed Claude skill, not the generated runtime copy
- Codex-only adaptation: edit the repo-managed Codex override, not the generated runtime copy
In this dotfiles setup, those live under:
claude-code/.claude/skills/<skill-name>/claude-code/codex-overrides/skills/<skill-name>/
Use a Codex override when the upstream shared skill exists but its workflow or wording does not cleanly fit Codex.
When to Create a Skill
Create or update a skill when:
- The technique is reusable across tasks
- The agent repeatedly misses the same judgment call
- A short document can prevent recurring mistakes
Do not create a skill for:
- One-off project context
- Purely mechanical rules that should be enforced by code or linting
- Content that belongs in repo instructions instead
Structure
Each skill directory should stay small:
skill-name/
SKILL.md
supporting-file.md # only when needed
Prefer one concise SKILL.md. Add supporting files only for heavy reference material.
Metadata Rules
Frontmatter supports only:
namedescription
Description rules:
- Start with
Use when... - Describe triggering conditions, not the workflow
- Stay specific enough for discovery
- Avoid harness-specific claims unless the skill is intentionally harness-specific
Authoring Rules
- Keep the workflow native to the target harness.
- Name real tools and files the agent actually has.
- Prefer concrete triggers over broad abstractions.
- Cut repeated explanations aggressively.
- Include red flags when the failure mode is predictable.
Testing the Skill
Validate the skill against realistic tasks:
- Observe baseline behavior on a representative request.
- Write or revise the skill to address the real failure.
- Re-run the task and compare behavior.
- Tighten wording only where the skill still leaves loopholes.
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.
- 6d ago First seen · 88 lines · 28 tokens per session scan A 1128393f611a
writing-skills is a skill published in the GitHub repository alleneubank/claude-code (52 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 28 tokens to every session and 549 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 2026-08-30.
Other skills, from other repositories
systematic-debugging
Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.
local-ai-agents
Build local-first AI agents that run entirely on a developer workstation with Microsoft Foundry Local and Qwen function-calling models. Covers Small Language Models (SLMs), the OpenAI-compatible local endpoint, sandboxed local tools, local RAG with Chroma, local MCP servers, hybrid cloud/local routing, and the…
chronicle
Analyze Copilot session history for standup reports, usage tips, session search, and session reindexing. Use when the user asks for a standup, daily summary, usage tips, workflow recommendations, wants to search or find past sessions by keyword/file/PR, wants to reindex their session store, or asks about deleting…
chat-pet-sprite-creation
Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.
cpu-profile-analysis
Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…
next-cache-components-adoption
Turn on Cache Components in a Next.js app and resolve the blocking routes it surfaces. Use when the user wants to enable, adopt, or migrate to Cache Components, flip the cacheComponents flag, work through a flood of blocking-prerender / instant validation errors, run the cache-components-instant-false codemod, or…