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 skills add Razaib-khan/ForgeWeave --skill skill-buildergit clone --depth 1 https://github.com/Razaib-khan/ForgeWeaveWrote 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/razaib-khan/forgeweave/skill-builder)<a href="https://agentmods.dev/skills/razaib-khan/forgeweave/skill-builder"><img src="https://agentmods.dev/badge/skills/razaib-khan/forgeweave/skill-builder/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.
<a href="https://agentmods.dev/skills/razaib-khan/forgeweave/skill-builder"><img src="https://agentmods.dev/badge/skills/razaib-khan/forgeweave/skill-builder.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00158 | $0.01853 |
| Opus 5.5 | $0.00063 | $0.00741 |
| Sonnet 5.5 | $0.00032 | $0.00371 |
| Haiku 4.5 | $0.00016 | $0.00185 |
Grade A, and why
skill-builder 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.
How it starts
The opening of the file, as written. The whole thing — 169 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Claude Skill Builder
Skills are the primary way to give Claude persistent, domain-specific expertise. A skill is a folder containing a SKILL.md file plus optional scripts, references, and assets — all discoverable and loadable on demand without bloating context.
Deep dive references:
references/anatomy.md— structure, file layout, frontmatter spec, progressive disclosurereferences/writing.md— writing patterns, style guide, description engineering, pitfallsreferences/evals.md— testing, grading, iteration loop, packaging
The Mental Model: Onboarding Guide for an Expert Hire
Building a skill is like writing an onboarding guide for a new hire who is already highly capable but lacks your specific organizational knowledge. They don't need to be told what code is. They need to know: your naming conventions, your deployment dance, which script to run when, and why you do things a certain way.
The implication: don't explain what Claude already knows. Only encode knowledge Claude can't infer from its training — your procedures, your environment's quirks, your tools' gotchas, your output standards.
Quick Decision: What Kind of Skill?
| Need | Skill Type |
|---|---|
| Teach a workflow with multiple steps | Procedural — numbered steps, decision tree |
| Wrap an environment's constraints (libraries, paths, formats) | Environmental — code snippets, gotcha table |
| Layer expert guidance on top of an MCP server | MCP Enhancement — workflow + tool guidance |
| Router that dispatches to other skills/files | Router — dispatch table, references/ per domain |
| Style or quality standard | Standard — constraints, examples of good/bad |
Most skills combine types. Decide the primary type first; it governs the opening structure.
The Core Loop
Identify gap → Draft SKILL.md → Test on 2-3 real prompts → Review outputs →
Revise based on what Claude actually did wrong → Repeat → Package
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.
- 1mo ago First seen · 169 lines · 158 tokens per session scan A ab181f8c19b1
skill-builder is a skill published in the GitHub repository Razaib-khan/ForgeWeave (1 stars, last pushed 4mo ago), licensed MIT. It adds 158 tokens to every session and 1,853 once invoked, about $0.0006 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 2026-08-31.
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