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/diet103/claude-code-infrastructure-showcase/skill-developernpx skills add diet103/claude-code-infrastructure-showcase --skill skill-developergit clone --depth 1 https://github.com/diet103/claude-code-infrastructure-showcaseWhat 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 | $0.00097 | $0.03354 |
| Opus 5 | $0.00048 | $0.01677 |
| Sonnet 5 | $0.00019 | $0.00671 |
| Haiku 4.5 | $0.00010 | $0.00335 |
Grade A, and why
skill-developer 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 3d 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.
Copies of this mod
5 near-identical copies found in the catalogue:
- skill-developer — 86% identical, 119 lines differ
- skill-developer — 86% identical, 54 lines differ
- skill-developer — 86% identical, 156 lines differ
- skill-developer — 86% identical, 54 lines differ
- skill-developer — 80% identical, 91 lines differ
How it starts
The opening of the file, as written. The whole thing — 449 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Skill Developer Guide
Purpose
Comprehensive guide for creating and managing skills in Claude Code with auto-activation system, following Anthropic's official best practices including the 500-line rule and progressive disclosure pattern.
When to Use This Skill
Automatically activates when you mention:
- Creating or adding skills
- Modifying skill triggers or rules
- Understanding how skill activation works
- Debugging skill activation issues
- Working with skill-rules.json
- Hook system mechanics
- Claude Code best practices
- Progressive disclosure
- YAML frontmatter
- 500-line rule
System Overview
Hook Architecture (five wired hooks)
1. UserPromptSubmit Hook (Proactive Suggestions)
- File:
.claude/hooks/skill-activation-prompt.ts - Trigger: BEFORE Claude sees user's prompt
- Purpose: Suggest relevant skills based on keywords + intent patterns (regex or optional AI classification)
- Method: Injects formatted reminder as context (stdout → Claude's input)
- Enforcement: Only
enforcement: "block"skills are marked MANDATORY;suggest/warnskills always appear as recommendations
2. PreToolUse Hook - Skill Verification Guard (Enforcement)
- File:
.claude/hooks/skill-verification-guard.ts - Trigger: BEFORE Edit/MultiEdit/Write executes
- Purpose: Enforce mandatory skill activation (two-try model) and guardrail file/content patterns; optional AI edit analysis
- Method: Exit code 2 + stderr blocks the tool; only
enforcement: "block"skills can block
3. PostToolUse Hook - Edit Tracker
- File:
.claude/hooks/post-tool-use-tracker.sh - Trigger: AFTER Edit/MultiEdit/Write completes
- Purpose: Track edited files and repos (feeds build checks and the error-handling reminder)
4. PostToolUse Hook - Skill Activation Tracker
- File:
.claude/hooks/skill-activation-tracker.ts - Trigger: AFTER the Skill tool runs
- Purpose: Clear the activated skill from pending lists so the guard stops blocking
What ships with it
6 files 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.
- 3d ago First seen · 449 lines · 97 tokens per session scan A bb3f8bd7400a
skill-developer is a skill published in the GitHub repository diet103/claude-code-infrastructure-showcase (10,016 stars, last pushed 1mo ago), licensed MIT. It adds 97 tokens to every session and 3,354 once invoked, about $0.0005 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.
brainstorming
You MUST use this before any creative work - creating features, building components, adding functionality, or modifying behavior. Explores user intent, requirements and design before implementation.
auto-perf-optimize
Run agent-driven VS Code performance or memory investigations. Use when asked to launch Code OSS, automate a VS Code scenario, run the Chat memory smoke runner, capture renderer heap snapshots, take workflow screenshots, compare run summaries, or drive a repeatable scenario before heap-snapshot analysis.
chat-perf
Run chat perf benchmarks and memory leak checks against the local dev build or any published VS Code version. Use when investigating chat rendering regressions, validating perf-sensitive changes to chat UI, or checking for memory leaks in the chat response pipeline.
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…