pulser

A diagnostic and testing tool for Claude Code skills. It checks skill files against a set of quality rules and reports issues with their structure, instructions, metadata, and usage guidance.

In plain words
What is it for?
It is for scanning one skill or a collection of skills, producing a report, and suggesting fixes for detected issues.
Why use it?
It helps find incomplete or inconsistent skill definitions before they cause problems during use.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/thestack-ai/pulser/skill
Any agent
npx skills add TheStack-ai/pulser --skill skill
Clone the repo
git clone --depth 1 https://github.com/TheStack-ai/pulser

Made for: Claude Code, Codex.

Per session 126 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 780 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00126 $0.00780
Opus 5 $0.00063 $0.00390
Sonnet 5 $0.00025 $0.00156
Haiku 4.5 $0.00013 $0.00078

Measured 2d ago against content hash e7bc5be2d916, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

pulser 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 2d 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.

skill/SKILL.md · 92 lines

How it starts

The opening of the file, as written. The whole thing — 92 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Pulser — Skill Diagnostics & Testing

Run pulser to diagnose and test Claude Code skills, then present results conversationally.

How to Run

pulser --format json ~/.claude/skills/

If pulser is not installed globally, use:

npx pulser-cli --format json ~/.claude/skills/

For a single skill:

pulser --format json --skill <name> ~/.claude/skills/

How to Present Results

  1. Run the command above and capture JSON output
  2. Parse the JSON result
  3. Present a conversational summary:
    • Total skills, score, healthy/warning/error counts
    • Top issues (max 5) with skill name + issue
    • "Fix these issues?" prompt
  4. If user says yes, apply prescriptions one by one:
    • Show the before/after diff
    • Ask for confirmation
    • Apply via Edit tool (NOT via --fix flag — you have more context than the CLI)

Summary Format

스킬 진단 완료:

📊 30개 스킬 스캔 | Score: 76/100
✓ 22 healthy  ⚠ 6 warnings  ✗ 2 errors

주요 이슈:
1. cardnews — Gotchas 없음, allowed-tools 미설정
2. geo-audit — 338줄 단일파일, Gotchas 없음
3. detailpage — Gotchas 없음, allowed-tools 미설정

고칠까요?

When Fixing

Use the prescription data from JSON. For each fix:

  • Read the actual SKILL.md file
  • Apply the suggested change using Edit tool
  • Verify the change makes sense in context
  • You can improve on the template prescriptions — you understand the skill's purpose

Eval — Skill Testing

Run pulser eval to test skills that have eval.yaml files:

pulser eval --format json

For a single skill:

pulser eval --format json --skill <name>

Present eval results conversationally:

  • Total tests, passed, failed, regressions
  • Failed test details with assertion info
  • Regression warnings (previously passing tests that now fail)

Gotchas

  1. Do not dump raw JSON to the user — always summarize conversationally
  2. If pulser is not installed, suggest npm install -g pulser-cli first
  3. For --fix operations, use Edit tool directly rather than CLI --fix (you have better context)
  4. Score below 50 is critical — highlight urgently
  5. Don't fix all skills at once — group by priority, confirm with user
  6. Eval only works for text-output skills (analysis, research, generation, reference) — execution-type skills cannot be tested this way
  7. Eval requires Claude Code CLI installed (claude -p must be available)

Read the full file on GitHub · 92 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. 2d ago First seen · 92 lines · 126 tokens per session scan A e7bc5be2d916

Subscribe to this mod's changes

pulser is a skill published in the GitHub repository TheStack-ai/pulser (18 stars, last pushed 2mo ago), licensed MIT. It adds 126 tokens to every session and 780 once invoked, about $0.0006 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.