Falco

fastly/fastly-agent-toolkit/skills/falco

by fastly6db70eaf54ba885d56091861224987d6cf06c429No licenseListed Oct 9, 2026Updated Oct 9, 2026

Lints, tests, simulates, and formats Fastly VCL code using the falco tool. Also serves as the authoritative VCL reference via the falco Go source, which implements Fastly's full VCL dialect. Use when validating VCL syntax, running VCL linting, testing VCL locally, simulating VCL request handling, formatting VCL files, writing VCL unit tests with assertions, debugging VCL logic errors, looking up VCL function signatures or variable scopes, understanding VCL subroutine behavior, or running `falco lint`/`falco simulate`/`falco test`/`falco fmt`. Also applies when working with VCL syntax errors, type mismatches in VCL, choosing which VCL subroutine to use, or setting up a local VCL development and testing environment.

Instructions onlySoftware Development

Add to a SourceWeft workspace

  1. Open the skill in your dashboard and add it to a workspace.
  2. Enable it for the chats that should use it.

This skill is instructions only: it ships no scripts to execute.

Add to SourceWeft

You will be asked to sign in first, then taken straight to this skill.

Ask your agent to install it

Paste this prompt into Claude Code, Codex, Cursor or another agent that can run commands — or into SourceWeft chat. The agent reads this skill's install guide, shows you its source, license and scripts, and installs it with the SourceWeft CLI once you agree.

Read https://sourceweft.com/skills/gh-fastly-fastly-agent-toolkit-falco-skills-falco-3ff9dd37e3c34a3e/install.md and install the skill it describes. Before installing, show me its source, license and whether it ships scripts, and wait for my OK. Ask me before changing anything else on my machine.

Read the install guide the agent follows

Install it yourself from a terminal

For Claude Code, Codex, Cursor and other local agents. The SourceWeft CLI fetches the skill from its source repository at the commit scanned here, and verifies every file against the hashes recorded when the skill was scanned. If anything differs, nothing is written.

npx @sourceweft/cli skills install @fastly/falco

Add --agent claude-code, codex, cursor or universal to choose which agent gets it (Claude Code by default).

Upstream installer — not verified by SourceWeft

The open-source skills installer fetches the same pinned commit, but does not check the files against the hashes SourceWeft recorded.

npx skills add https://github.com/fastly/fastly-agent-toolkit/tree/6db70eaf54ba885d56091861224987d6cf06c429/skills/falco

Source and attribution

Source:fastly/fastly-agent-toolkitinskills/falcoat commit6db70ea

License: No license

Content belongs to its original authors. SourceWeft indexes it from a public repository.

Report or request removal