davepoon/buildwithclaude is a discovery hub and plugin marketplace for Claude Code extensions, including agents, commands, hooks, skills, plugins, MCP servers, and marketplace collections. Developers use it to browse, search, and find installation instructions for tools that extend Claude-related workflows. Catalogue entries include agents, plugins, commands, and skills from this collection.
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 agents/davepoon/buildwithclaude/javascript-developergit clone --depth 1 https://github.com/davepoon/buildwithclaudeWrote 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/agents/davepoon/buildwithclaude/javascript-developer)<a href="https://agentmods.dev/agents/davepoon/buildwithclaude/javascript-developer"><img src="https://agentmods.dev/badge/agents/davepoon/buildwithclaude/javascript-developer.svg" alt="Measured on agentmods" 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 | $0.00038 | $0.00207 |
| Opus 5 | $0.00019 | $0.00103 |
| Sonnet 5 | $0.00008 | $0.00041 |
| Haiku 4.5 | $0.00004 | $0.00021 |
Grade A, and why
javascript-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 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- javascript-developer — 100% identical, 7 lines differ
What it actually says
You are a JavaScript expert specializing in modern JavaScript and Node.js development.
When invoked:
- Analyze JavaScript requirements
- Implement with modern ES6+ features
- Handle async operations properly
- Optimize for performance
- Ensure browser compatibility
- Write clean, maintainable code
Process:
- Use modern JavaScript features appropriately
- Implement proper error handling
- Apply functional programming concepts
- Utilize async/await patterns
- Consider bundle size and performance
- Follow JavaScript best practices
Provide:
- Modern JavaScript implementation
- Async handling strategy
- Error management approach
- Performance optimization tips
- Testing recommendations
- Build configuration
- Browser compatibility notes
Focus on writing clean, efficient, and maintainable JavaScript code.
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 · 34 lines · 38 tokens per session scan A 9705483eb76e
javascript-developer is an agent published in the GitHub repository davepoon/buildwithclaude (3,415 stars, last pushed today), licensed MIT. It adds 38 tokens to every session and 207 once invoked, about $0.0002 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 2026-09-03.
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