skill-writer

skill-writer is a skill for Claude Code, Codex from lessweb/deepcode-cli. It costs 59 tokens per session (2,229 once invoked), scanned A, original, MIT.

A guide for creating and maintaining Agent Skills, which are instruction packages that teach AI agents how to handle specific kinds of work.

In plain words
What is it for?
Use it to plan a skill's scope, write or update its SKILL.md file, set its metadata, and check its structure.
Why use it?
It helps avoid unclear instructions, invalid files, and discovery problems when building or changing a skill.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to plan a skill's scope, write or update its SKILL.md file, set its metadata, and check its structure.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/lessweb/deepcode-cli/skill-writer
About the project

Deep Code CLI is a terminal-based AI coding assistant optimized for the DeepSeek V4 model, with controls for reasoning depth and support for extensible agent skills. Developers use it to work with code from any project directory. The catalogue skills extend its capabilities.

lessweb/deepcode-cli · 2,158 stars · on GitHub · deepcode.vegamo.cn

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 lessweb/deepcode-cli --skill skill-writer
Clone the repo
git clone --depth 1 https://github.com/lessweb/deepcode-cli

Made for: Claude Code, Codex.

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 skill-writer

README.md
[![agentmods](https://agentmods.dev/badge/skills/lessweb/deepcode-cli/skill-writer/github.svg)](https://agentmods.dev/skills/lessweb/deepcode-cli/skill-writer)
Your own site
<a href="https://agentmods.dev/skills/lessweb/deepcode-cli/skill-writer"><img src="https://agentmods.dev/badge/skills/lessweb/deepcode-cli/skill-writer/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 skill-writer

Your own site · 80×15
<a href="https://agentmods.dev/skills/lessweb/deepcode-cli/skill-writer"><img src="https://agentmods.dev/badge/skills/lessweb/deepcode-cli/skill-writer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 59 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,229 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 warn 7 Sept 2026
SkillSpector: 4 findings, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Rogue Agent · line 77
    Skill modifies its own code, configuration, or behavior at runtime. Self-modification enables an agent to escalate privileges, disable safety constraints, or install persistent backdoors.
    Fix: Prevent the skill from modifying its own code, SKILL.md, or configuration files. Treat skill files as read-only at runtime.
  • medium Rogue Agent · line 8
    Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.
    Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
  • medium Agent Snooping · line 269
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
  • medium Agent Snooping · line 270
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
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 $0.00059 $0.02229
Opus 5.5 $0.00024 $0.00892
Sonnet 5.5 $0.00012 $0.00446
Haiku 4.5 $0.00006 $0.00223

Measured 1mo ago against content hash 05cd9502973f, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

skill-writer 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 1mo 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.

packages/core/templates/skills/bundled/skill-writer/SKILL.md · 403 lines

How it starts

The opening of the file, as written. The whole thing — 403 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill Writer

This Skill helps you create well-structured Agent Skills for AI agents that follow best practices and validation requirements.

When to use this Skill

Use this Skill when:

  • Creating a new Agent Skill
  • Writing or updating SKILL.md files
  • Designing skill structure and frontmatter
  • Troubleshooting skill discovery issues
  • Converting existing prompts or workflows into Skills

Instructions

Step 1: Determine Skill scope

First, understand what the Skill should do:

  1. Ask clarifying questions:

    • What specific capability should this Skill provide?
    • When should AI agents use this Skill?
    • What tools or resources does it need?
    • Is this for personal use or team sharing?
  2. Keep it focused: One Skill = one capability

    • Good: "PDF form filling", "Excel data analysis"
    • Too broad: "Document processing", "Data tools"

Step 2: Choose Skill location

Determine where to create the Skill:

Personal Skills (~/.agents/skills/):

  • Individual workflows and preferences
  • Experimental Skills
  • Personal productivity tools

Project Skills (.agents/skills/):

  • Team workflows and conventions
  • Project-specific expertise
  • Shared utilities (committed to git)

Step 3: Create Skill structure

Create the directory and files:

# Personal
mkdir -p ~/.agents/skills/skill-name

# Project
mkdir -p .agents/skills/skill-name

For multi-file Skills:

skill-name/
├── SKILL.md (required)
├── reference.md (optional)
├── examples.md (optional)
├── scripts/
│   └── helper.py (optional)
└── templates/
    └── template.txt (optional)

Step 4: Write SKILL.md frontmatter

Create YAML frontmatter with required fields:

---
name: skill-name
description: Brief description of what this does and when to use it
---

Field requirements:

  • name:
    • Lowercase letters, numbers, hyphens only
    • Max 64 characters
    • Must match directory name
    • Good: pdf-processor, git-commit-helper
    • Bad: PDF_Processor, Git Commits!

Read the full file on GitHub · 403 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. 1mo ago First seen · 403 lines · 59 tokens per session scan A 05cd9502973f

Subscribe to this mod's changes

skill-writer is a skill published in the GitHub repository lessweb/deepcode-cli (2,158 stars, last pushed yesterday), licensed MIT. It adds 59 tokens to every session and 2,229 once invoked, about $0.0002 per session on Opus 5.5. 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.

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