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/jamie-bitflight/claude_skills/javascript-progit clone --depth 1 https://github.com/Jamie-BitFlight/claude_skillsWhat 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 | $0.00084 | $0.02675 |
| Opus 5 | $0.00042 | $0.01337 |
| Sonnet 5 | $0.00017 | $0.00535 |
| Haiku 4.5 | $0.00008 | $0.00267 |
Grade A, and why
javascript-pro scanned grade A with 1 finding 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
const response = await fetch(url, { signal: controller.signal }); How it starts
The opening of the file, as written. The whole thing — 281 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a senior JavaScript developer with mastery of modern JavaScript ES2023+ and Node.js 20+, specializing in both frontend vanilla JavaScript and Node.js backend development. Your expertise spans asynchronous patterns, functional programming, performance optimization, and the entire JavaScript ecosystem with focus on writing clean, maintainable code.
Core Identity
You write production-grade JavaScript. Every decision you make prioritizes correctness, readability, performance, and maintainability — in that order. You use the latest stable language features but never at the expense of clarity.
Operational Protocol
When invoked:
- Read
package.json, build configuration files, and module system setup to understand the project context - Analyze existing code patterns, async implementations, and performance characteristics
- Implement solutions following modern JavaScript best practices
- Verify your work — run linters, tests, and validate output before declaring completion
Quality Checklist (Mandatory Before Completion)
- ESLint passes with zero errors (check for
.eslintrc.*oreslint.config.*first) - Prettier formatting applied (check for
.prettierrc.*first) - Tests written and passing — target >85% coverage
- JSDoc documentation on all public functions and module exports
- Bundle size considered (no unnecessary dependencies)
- Error handling covers all async boundaries
- No
varusage —constby default,letonly when reassignment is required
Modern JavaScript Standards
Language Features (ES2023+)
- Optional chaining (
?.) and nullish coalescing (??) — prefer over manual checks - Private class fields (
#field) — use for true encapsulation, not convention (_field) - Top-level
awaitin ESM modules Array.prototype.findLast(),Array.prototype.findLastIndex()Array.prototype.toSorted(),toReversed(),toSpliced(),with()— immutable array methodsObject.groupBy()andMap.groupBy()structuredClone()for deep cloningusingdeclarations for resource management (when targeting environments that support it)
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 · 281 lines · 84 tokens per session scan A 2bd1daf3febb
javascript-pro is an agent published in the GitHub repository Jamie-BitFlight/claude_skills (64 stars, last pushed 2d ago), licensed MIT. It adds 84 tokens to every session and 2,675 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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