Fastly Agent Toolkit

Fastly Agent Toolkit

A collection of skills for AI coding agents to work with the Fastly platform and edge computing tools.

Available skills

• fastly: Working with the Fastly platform, including services, caching, VCL, WAF, TLS, DDoS protection, purging, and API usage.
• fastly-cli: Using the Fastly CLI to manage services, compute apps, logging, WAF, TLS, key-value stores, and stats.
• fastly-fiddle: Testing VCL against real Fastly edge infrastructure with Fastly Fiddle, covering assertion-based tests, the Fiddle HTTP API, shareable bug reproductions, and CI integration.
• falco: VCL development with Falco, covering linting, testing, simulation, formatting, REPL, and Terraform integration.
• fastlike: Running Fastly Compute locally with Fastlike (Go-based), covering backend configuration, builds, and testing.
• viceroy: Running Fastly Compute locally with Viceroy (WASM-based), covering serving, configuration, testing, and SDK adaptation.
• xvcl: The XVCL VCL transpiler, covering syntax extensions, subroutines, header manipulation, and caching logic.

Each skill lives under skills/ with a SKILL.md entrypoint and a references/ directory containing detailed topic files.

Important: SKILL.md files reference companion files in their references/ directory. Make sure your agent is allowed to read from these directories, otherwise it won't be able to follow the references and will miss important context.

Usage

Pick the skills relevant to your project. You probably don't need all of them.

Using the skills CLI (recommended)

The skills CLI installs skills into the standard .agents/skills/ directory and automatically symlinks them into agent-specific directories. It supports most agents out of the box.

Install into the current project:

bunx skills add github:fastly/fastly-agent-toolkit --skill falco --skill viceroy
# or with node:
npx skills add github:fastly/fastly-agent-toolkit --skill falco --skill viceroy

Install globally (available across all projects via ~/.agents/skills/):

bunx skills add -g github:fastly/fastly-agent-toolkit --skill falco --skill viceroy

Manual copy

If your agent supports the .agents/skills/ convention, this is the most portable option. Agents that use this location include Amp, Cline, Codex, Cursor, Gemini CLI, GitHub Copilot, Kimi Code, OpenCode, Replit Agent, Swival, and Warp.

Install into the current project:

mkdir -p .agents/skills
cp -R ./skills/{falco,viceroy} .agents/skills/

Install globally (for agents that support ~/.agents/skills/):

mkdir -p ~/.agents/skills
cp -R ./skills/{falco,viceroy} ~/.agents/skills/

If your agent doesn't support .agents/skills/, use its agent-specific location below.

Claude Code

Plugin Marketplace

claude plugin install fastly-agent-toolkit@claude-plugins-official
claude plugin list

# If this fails, add skills manually in the next section.

Manual

mkdir -p .claude/skills
cp -R ./skills/{falco,viceroy} .claude/skills/

For a quick local setup, the manual copy is more reliable since it doesn't depend on the marketplace.

Codex

mkdir -p ~/.codex/skills
cp -R ./skills/{falco,viceroy} ~/.codex/skills/

Swival

Stage the collection in your library first, then add the skills you want:

swival skills add --global https://github.com/fastly/fastly-agent-toolkit  # stage into ~/.config/swival/library
swival skills add fastly-agent-toolkit                                     # install the collection into this project
swival skills add --global fastly-agent-toolkit                            # or activate it in every project

Prefer only a couple of skills? Activate them by name instead of the whole collection: swival skills add falco, swival skills add viceroy.

Qwen Code

Qwen Code requires the experimental skills feature. Enable it by adding to .qwen/settings.json:

{
  "tools": {
    "experimental": {
      "skills": true
    }
  }
}

Then copy skills to the project directory:

mkdir -p .qwen/skills
cp -R ./skills/{falco,viceroy} .qwen/skills/

Gemini CLI

Gemini CLI supports .agents/skills/ as shown above. You can also link the whole repository using Gemini's extension workflow:

gemini extensions link .

Swap {falco,viceroy} for whatever combination you need. For VCL work, falco and xvcl are the most useful. For Fastly Compute, grab fastly-cli and either viceroy or fastlike.

Skill format

Each skill lives in its own directory as a SKILL.md file with YAML frontmatter following the Agent Skills spec.