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 mgiovani/cc-arsenal --skill implement-featuregit clone --depth 1 https://github.com/mgiovani/cc-arsenalWrote 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/mgiovani/cc-arsenal/implement-feature)<a href="https://agentmods.dev/skills/mgiovani/cc-arsenal/implement-feature"><img src="https://agentmods.dev/badge/skills/mgiovani/cc-arsenal/implement-feature/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/mgiovani/cc-arsenal/implement-feature"><img src="https://agentmods.dev/badge/skills/mgiovani/cc-arsenal/implement-feature.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00134 | $0.02978 |
| Opus 5.5 | $0.00054 | $0.01191 |
| Sonnet 5.5 | $0.00027 | $0.00596 |
| Haiku 4.5 | $0.00013 | $0.00298 |
Grade A, and why
implement-feature 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 22d 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 — 260 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Feature Implementation
Implement a new feature as a Senior Staff Engineer would (SOLID, DRY, YAGNI) to produce a secure, fast, reliable change.
This skill produces exactly one of two outputs: an implemented feature (Phases 0-6 below), or (when the Ambiguity Gate at the start of Phase 0 fails) 2-3 clarifying questions and nothing else. Never both in the same turn.
Feature to Implement
$ARGUMENTS
Anti-hallucination guidelines
Before implementing anything:
- Discover project commands first: do not assume
bun,npm,make, etc. exist. - Read CLAUDE.md: every project has different conventions.
- Verify tools exist: check for
Makefile,justfile,package.json,pyproject.toml. - Never guess the test command: find the one this project actually uses.
- Any number reported at the end (files changed, tests added, pass count) must come from a command actually run in this session: never state a count or percentage you didn't verify by running something.
Lean Code
Write the smallest change that fully does the job, and that the next person can change without fear. Two goals at once: minimal footprint, easy to change.
Before you add code, search this codebase, the standard library, the framework, and installed dependencies first: reuse beats reimplementation. Build only what a current, concrete requirement needs, skip speculative flags, options, or extension points for a future that may never come. Watch for abstraction that isn't earning its keep: no interface with a single implementation, no factory for one product, no wrapper that only forwards; add indirection once a second caller actually appears.
While you write it, put logic where a future change touches one spot, fixing the shared function once instead of guarding every caller. Favor the change that reuses or deletes code over the one that adds it, fewer files and a shorter diff, as long as it stays complete. Trace the real flow of the code you touch, end to end, before changing it: a tiny diff written without understanding is a liability, not lean.
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.
- 22d ago Changed · -1 lines 17626f97bfca
- 1mo ago Changed · -9 lines 81fde3abba2c
- 1mo ago Changed · -7 tokens per session 22ac9d3dca89
- 1mo ago Changed · +2 lines 5655a5347204
- 1mo ago First seen · 268 lines · 141 tokens per session scan A 844d4be75765
implement-feature is a skill published in the GitHub repository mgiovani/cc-arsenal (8 stars, last pushed 2d ago), licensed MIT. It adds 134 tokens to every session and 2,978 once invoked, about $0.0005 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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