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/mp-web3/claude-starter-kit/create-skillnpx skills add mp-web3/claude-starter-kit --skill create-skillgit clone --depth 1 https://github.com/mp-web3/claude-starter-kitWhat 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 | $0.00052 | $0.00970 |
| Opus 5 | $0.00026 | $0.00485 |
| Sonnet 5 | $0.00010 | $0.00194 |
| Haiku 4.5 | $0.00005 | $0.00097 |
Grade A, and why
create-skill 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.
How it starts
The opening of the file, as written. The whole thing — 117 lines — stays where its author put it; the contents beside it link to each section on GitHub.
/create-skill — Skill Builder
First: Read LEARNINGS.md in this skill's directory.
Arguments: $ARGUMENTS
Process
Step 1: Understand
If $ARGUMENTS provides a skill name and description, proceed. Otherwise ask:
- What should this skill do? (one sentence)
- When should it trigger? (what would the user say/do?)
- What resources does it need? (scripts, reference docs, templates?)
Keep questions to one message. Don't over-interview.
Step 2: Scaffold
Run the init script:
python3 .claude/skills/create-skill/scripts/init_skill.py <skill-name> --path .claude/skills
This creates the directory with template files. If --path is omitted, defaults to .claude/skills in the current workspace.
Step 3: Write SKILL.md
Replace the template content. Follow these rules:
Frontmatter (required):
name: kebab-case, max 64 chars. Becomes the/slash-command.description: Comprehensive. This is how Claude decides when to activate. Include trigger phrases, contexts, use cases.
Frontmatter (optional, add only when needed):
allowed-tools: Restrict tool access (e.g.,Read, Grep, Glob, Bash)argument-hint: Autocomplete hint (e.g.,[filename],[--dry-run])fork: true: Run as sub-agent (use for data-heavy skills that would bloat main context)disable-model-invocation: true: Manual/nameonly, no auto-trigger
Body rules:
- Start with "Read LEARNINGS.md" instruction
- Use
$ARGUMENTSplaceholder for user input - Imperative form ("Run the script", not "You should run the script")
- Keep under 500 lines. Split longer content into
references/files. - Reference bundled resources with relative paths + describe when to read them
- Match freedom to fragility: exact scripts for brittle ops, text guidance for flexible tasks
Body structure (adapt as needed):
# /name -- One-Line Summary
**First:** Read `LEARNINGS.md` in this skill's directory.
**Arguments:** `$ARGUMENTS`
## Step 1: [Name]
[What to do, expected outcome]
## Step 2: [Name]
[What to do, expected outcome]
## Rules
[Constraints, gotchas, things to never do]
What ships with it
3 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.
- 2d ago First seen · 117 lines · 52 tokens per session scan A 3011b1dad619
create-skill is a skill published in the GitHub repository mp-web3/claude-starter-kit (106 stars, last pushed 5mo ago), licensed MIT. It adds 52 tokens to every session and 970 once invoked, about $0.0003 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.
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