act

act is a skill for Claude Code from vinnie357/claude-skills. It costs 27 tokens per session (2,429 once invoked), scanned B, original, MIT.

A guide to using act, a command-line tool that runs GitHub Actions workflows on your own computer. It uses Docker containers to imitate GitHub's hosted runner environment.

In plain words
What is it for?
Use it to list workflows, run jobs locally, inspect workflow output, and troubleshoot GitHub Actions with Docker.
Why use it?
It lets you test workflow changes before pushing them to GitHub, which shortens the feedback loop when debugging failed jobs.

Skill for Claude Code

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

Part of the github plugin — 5 skills, 4 agents shipped together

Good fit Use it to list workflows, run jobs locally, inspect workflow output, and troubleshoot GitHub Actions with Docker.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/vinnie357/claude-skills/act
Install

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.

Any agent
npx skills add vinnie357/claude-skills --skill act
Clone the repo
git clone --depth 1 https://github.com/vinnie357/claude-skills

Made for: Claude Code.

Or install github, the plugin that ships this one along with the rest of its 5 skills, 4 agents.

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 act

README.md
[![agentmods](https://agentmods.dev/badge/skills/vinnie357/claude-skills/act/github.svg)](https://agentmods.dev/skills/vinnie357/claude-skills/act)
Your own site
<a href="https://agentmods.dev/skills/vinnie357/claude-skills/act"><img src="https://agentmods.dev/badge/skills/vinnie357/claude-skills/act/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.

agentmods 80×15 button for act

Your own site · 80×15
<a href="https://agentmods.dev/skills/vinnie357/claude-skills/act"><img src="https://agentmods.dev/badge/skills/vinnie357/claude-skills/act.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 27 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,429 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 $0.00027 $0.02429
Opus 5 $0.00014 $0.01215
Sonnet 5 $0.00005 $0.00486
Haiku 4.5 $0.00003 $0.00243

Measured 5d ago against content hash 17386e458c13, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade B, and why

act 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 5d 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.

sudo systemctl start docker
plugins/tools/github/skills/act/SKILL.md · 444 lines

How it starts

The opening of the file, as written. The whole thing — 444 lines — stays where its author put it; the contents beside it link to each section on GitHub.

act - Local GitHub Actions Testing

Activate when testing GitHub Actions workflows locally, debugging workflow issues, or developing actions without committing to remote repositories. This skill covers act installation, configuration, and usage patterns.

Installation

Install via mise: mise install act (pinned in the github plugin's mise.toml), then verify with act --version. Homebrew, Linux script, source, and Chocolatey methods: see references/setup-and-config.md.

How act Works

act reads workflow files from .github/workflows/ and:

  1. Determines which actions and jobs to execute
  2. Pulls or builds required Docker images
  3. Creates containers matching GitHub's runner environment
  4. Executes steps in isolated containers
  5. Provides output matching GitHub Actions format

Key Concept: act uses Docker to simulate GitHub's runner environment locally.

Prerequisites

act requires a running Docker daemon (verify with docker ps) and valid .github/workflows/*.yml files. Details: see references/setup-and-config.md.

Basic Usage

List Available Workflows

# List all workflows
act -l

# Output:
# Stage  Job ID  Job name  Workflow name  Workflow file  Events
# 0      build   build     CI             ci.yml         push,pull_request
# 0      test    test      CI             ci.yml         push,pull_request

Run Default Event (push)

# Run all jobs triggered by push event
act

# Run specific job
act -j build

# Run specific workflow
act -W .github/workflows/ci.yml

Run Specific Events

# Pull request event
act pull_request

# Manual workflow dispatch
act workflow_dispatch

# Push to specific branch
act push -e .github/workflows/push-event.json

# Schedule event
act schedule

Dry Run

# Show what would run without executing
act -n

# Show with full details
act -n -v

Event Payloads

Custom event JSON and workflow_dispatch input payloads, passed with -e file.json: see references/setup-and-config.md. A worked PR-event example stays under Common Patterns below.

Read the full file on GitHub · 444 lines

Files

What ships with it

2 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.

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. 5d ago First seen · 444 lines · 27 tokens per session scan B 17386e458c13

Subscribe to this mod's changes

act is a skill published in the GitHub repository vinnie357/claude-skills (25 stars, last pushed 3d ago), licensed MIT. It adds 27 tokens to every session and 2,429 once invoked, about $0.0001 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.

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