Borrowing it
Nothing to install: this file belongs to Rosenfan/Matrix. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/Rosenfan/Matrix/master/.claude/skills/matrix-claude/SKILL.mdgit clone --depth 1 https://github.com/Rosenfan/MatrixWrote 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/rosenfan/matrix/matrix-claude)<a href="https://agentmods.dev/skills/rosenfan/matrix/matrix-claude"><img src="https://agentmods.dev/badge/skills/rosenfan/matrix/matrix-claude.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 5.1 | $0.00035 | $0.00998 |
| Opus 5 | $0.00017 | $0.00499 |
| Sonnet 5 | $0.00007 | $0.00200 |
| Haiku 4.5 | $0.00003 | $0.00100 |
Grade A, and why
matrix-claude 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 — 99 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Matrix Claude Handoff
This is an optional Matrix sidecar, not a Matrix phase. It must not call transition, archive, or write matrix.yaml or events.jsonl. It supports only a matching full or legacy-full three-artifact Contract; new lightweight hotfix/tweak changes are intentionally unsupported.
Use artifact_language from inspect for human-readable handoff text while retaining the stable machine-readable headings and metadata keys.
When to Use
Use $matrix-claude when:
- The active change is in Build and the Design -> Build transition has approved the contract
- You want Claude Code (instead of Codex) to implement the design
- You need a bounded task package with all implementation details
Preconditions
The exporter performs this read-only check before writing anything:
node <matrix-skill-directory>/scripts/matrix-runtime.mjs guard build
If matrix is genuinely absent from PATH, use the bundled runtime from the installed root Matrix Skill. Do not fall back when the primary command starts and returns an error.
If the build guard reports CONTRACT_CHANGED or CONTRACT_UNAPPROVED, return to $matrix-design and approve a new contract through Build. The exporter reads the approved bytes of proposal.md, design.md, and plan.md; it does not invent missing facts.
Export
Treat explicit invocation of $matrix-claude as the user's choice of Claude Code as the implementation actor. Generate the package with the deterministic exporter; it refuses a non-matching approved contract and does not alter Matrix state.
# Generic project: only exports a Matrix artifact.
node <matrix-skill-directory>/scripts/matrix-runtime.mjs export --task-id <ID> --target generic
# FnSec: exports its formal task package. Add --apply-fnsec-board only when
# active.md is NO_ACTIVE_OBJECTIVE; an existing task is never overwritten.
node <matrix-skill-directory>/scripts/matrix-runtime.mjs export --task-id <ID> --target fnsec --apply-fnsec-board
What ships with it
1 file 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 Changed 454391ee978c
- 6d ago First seen · 99 lines · 35 tokens per session scan A d0f160949a75
matrix-claude is a skill published in the GitHub repository Rosenfan/Matrix (5 stars, last pushed 4d ago), licensed MIT. It adds 35 tokens to every session and 998 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 2026-08-31.
Other skills, from other repositories
systematic-debugging
Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.
local-ai-agents
Build local-first AI agents that run entirely on a developer workstation with Microsoft Foundry Local and Qwen function-calling models. Covers Small Language Models (SLMs), the OpenAI-compatible local endpoint, sandboxed local tools, local RAG with Chroma, local MCP servers, hybrid cloud/local routing, and the…
next-cache-components-adoption
Turn on Cache Components in a Next.js app and resolve the blocking routes it surfaces. Use when the user wants to enable, adopt, or migrate to Cache Components, flip the cacheComponents flag, work through a flood of blocking-prerender / instant validation errors, run the cache-components-instant-false codemod, or…
chat-pet-sprite-creation
Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.
cpu-profile-analysis
Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…
insight-error-page
Write or audit an insight-kind error page for the Next.js dev overlay. Use when creating a new errors/ .mdx page, auditing an existing one, or checking that a page matches the framework fix cards. Covers page structure, title alignment, FixCard cards with Copy prompt button, code snippets, terminology verification…