matrix-optimizer

matrix-optimizer is a skill for Claude Code from armanzeroeight/fastagent-plugins. It costs 60 tokens per session (2,539 once invoked), scanned B, original, MIT.

A guide to configuring GitHub Actions test matrices across combinations such as operating systems, language versions, architectures, databases, and feature settings. A matrix creates separate workflow jobs for each selected combination.

In plain words
What is it for?
Use it to configure multi-version or cross-platform tests and improve matrix settings, caching, parallel work, and job combinations.
Why use it?
It helps test more environments while controlling duplicated work and CI resource use.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is uses: ./.github/workflows/reusable-matrix.yml.

Part of the github-actions-toolkit plugin — 2 skills shipped together

Good fit Use it to configure multi-version or cross-platform tests and improve matrix settings, caching, parallel work, and job combinations.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/armanzeroeight/fastagent-plugins
agentmods
npx agentmods add skills/armanzeroeight/fastagent-plugins/matrix-optimizer

Made for: Claude Code.

Or install github-actions-toolkit, the plugin that ships this one along with the rest of its 2 skills.

Wrote 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.

agentmods badge for matrix-optimizer

README.md
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Your own site
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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.

agentmods 80×15 button for matrix-optimizer

Your own site · 80×15
<a href="https://agentmods.dev/skills/armanzeroeight/fastagent-plugins/matrix-optimizer"><img src="https://agentmods.dev/badge/skills/armanzeroeight/fastagent-plugins/matrix-optimizer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 60 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,539 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00060 $0.02539
Opus 5 $0.00030 $0.01269
Sonnet 5 $0.00012 $0.00508
Haiku 4.5 $0.00006 $0.00254

Measured 6d ago against content hash a6dfb6dd9db8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade B, and why

matrix-optimizer scanned grade B 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 6d 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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

install-cmd: sudo apt-get install
plugins/github-actions-toolkit/skills/matrix-optimizer/SKILL.md · 423 lines

How it starts

The opening of the file, as written. The whole thing — 423 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Matrix Optimizer

Configure and optimize GitHub Actions matrix strategies for efficient multi-version and multi-platform testing.

Quick Start

Basic matrix for testing multiple Node.js versions:

strategy:
  matrix:
    node-version: [16, 18, 20]

Instructions

Step 1: Identify Matrix Dimensions

Common matrix dimensions:

  • Language versions: Node.js, Python, Ruby, Go versions
  • Operating systems: ubuntu, macos, windows
  • Architectures: x64, arm64
  • Dependency versions: Database versions, framework versions
  • Feature flags: Different configuration options

Example dimensions:

strategy:
  matrix:
    os: [ubuntu-latest, macos-latest, windows-latest]
    node-version: [16, 18, 20]
    # This creates 9 jobs (3 OS × 3 versions)

Step 2: Configure Matrix Strategy

Basic matrix:

jobs:
  test:
    runs-on: ${{ matrix.os }}
    strategy:
      matrix:
        os: [ubuntu-latest, macos-latest]
        node-version: [18, 20]
    steps:
      - uses: actions/checkout@v3
      - uses: actions/setup-node@v3
        with:
          node-version: ${{ matrix.node-version }}
      - run: npm test

Matrix with include:

strategy:
  matrix:
    os: [ubuntu-latest, macos-latest]
    node-version: [18, 20]
    include:
      # Add specific combination
      - os: windows-latest
        node-version: 20
      # Add extra variables for specific combination
      - os: ubuntu-latest
        node-version: 20
        experimental: true

Matrix with exclude:

strategy:
  matrix:
    os: [ubuntu-latest, macos-latest, windows-latest]
    node-version: [16, 18, 20]
    exclude:
      # Skip Node 16 on Windows
      - os: windows-latest
        node-version: 16
      # Skip Node 16 on macOS
      - os: macos-latest
        node-version: 16

Step 3: Optimize for Cost and Speed

Fail-fast strategy:

strategy:
  fail-fast: false  # Continue all jobs even if one fails
  matrix:
    node-version: [16, 18, 20]

Read the full file on GitHub · 423 lines

Changes

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.

  1. 6d ago First seen · 423 lines · 60 tokens per session scan B a6dfb6dd9db8

Subscribe to this mod's changes

matrix-optimizer is a skill published in the GitHub repository armanzeroeight/fastagent-plugins (29 stars, last pushed 1mo ago), licensed MIT. It adds 60 tokens to every session and 2,539 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.