Is the Firefox CLI skill free?

Yes. The skill itself is free from respawn-llc/firefox-cli. SkillProof publishes the install command and an independent test verdict at no cost.

What is the Firefox CLI SkillProof Score?

6.8/10 — installs cleanly 3/5, triggers reliably 5/5, output vs. baseline 6/10, docs & honesty 3/5.

How do I install Firefox CLI?

Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.

Can I use Firefox CLI with Cursor, Copilot, Gemini CLI, Codex or other AI tools?

The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.

Firefox CLI

Terminal control of the user's real, authenticated Firefox - but the skill folder ships zero setup help.

by respawn-llc · respawn-llc/firefox-cli

Works with setup

Install — copy the command Download source ↗

Test report

Verdict: Works with setup
Score: 6.8/10
Tested: Jul 15, 2026
Environment: Claude Code 2.x (agent harness)
Upstream re-checked: Aug 10, 2026 · 442b821

The skill folder is a single 70-line SKILL.md with no bundled scripts and no install instructions at all - it silently assumes 'firefox-cli' is already on PATH, paired with a signed Firefox extension, and approved by the user. Installed the real npm package (firefox-cli@0.2.0, confirmed live on the npm registry) into an isolated prefix and ran it for real: 'doctor' correctly reported the native-host manifest missing and the extension disconnected, and 'snapshot -i' failed with an honest, non-destructive setup-required error - so the tool itself is legit, but nothing in the shipped skill folder gets a user there.

Scored on four weighted criteria — install, triggering, output vs. baseline, docs. How scoring works

Installs cleanly 3/5
Triggers reliably 5/5
Output vs. baseline 6/10
Docs & honesty 3/5

What Firefox CLI does

Documents the firefox-cli command surface (open, snapshot, tab/window control, click, wait, screenshots) so an agent drives the user's actual authenticated Firefox session instead of guessing flags. Triggers when a task needs the user's real browser/session state; the skill explicitly says not to use it as a web-search substitute. Requires a separately installed npm CLI, a signed Firefox extension, and native-host pairing that the skill itself never mentions.

How to install Firefox CLI

git clone https://github.com/respawn-llc/firefox-cli.git
mkdir -p ~/.claude/skills
cp -r firefox-cli/skills/firefox-cli ~/.claude/skills/firefox-cli
# ALSO REQUIRED (not in the skill folder): npm install -g firefox-cli && firefox-cli setup && install the extension it prints + firefox-cli setup native-host && firefox-cli connect

Skills live in ~/.claude/skills/ (global) or .claude/skills/ (per-project). Restart Claude Code after installing.

Commands — how to trigger Firefox CLI

/firefox-cli Terminal control of the user's real, authenticated Firefox - but the skill folder ships zero setup help.

It also activates on plain-language prompts like these:

Take a screenshot of the page currently open in my Firefox tab.
Log into my email in Firefox and check for a message from Jane.
Click the checkout button in my browser and tell me if it's enabled.

Frequently asked questions

Is the Firefox CLI skill free?: Yes. The skill itself is free from respawn-llc/firefox-cli. SkillProof publishes the install command and an independent test verdict at no cost.
Does Firefox CLI work with Claude Code?: We tested it with Claude Code 2.x (agent harness) on Jul 15, 2026. Verdict: Works with setup. The skill folder is a single 70-line SKILL.md with no bundled scripts and no install instructions at all - it silently assumes 'firefox-cli' is already on PATH, paired with a signed Firefox extension, and approved by the user. Installed the real npm package (firefox-cli@0.2.0, confirmed live on the npm registry) into an isolated prefix and ran it for real: 'doctor' correctly reported the native-host manifest missing and the extension disconnected, and 'snapshot -i' failed with an honest, non-destructive setup-required error - so the tool itself is legit, but nothing in the shipped skill folder gets a user there.
What is the Firefox CLI SkillProof Score?: 6.8/10 — installs cleanly 3/5, triggers reliably 5/5, output vs. baseline 6/10, docs & honesty 3/5.
How do I install Firefox CLI?: Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.
Can I use Firefox CLI with Cursor, Copilot, Gemini CLI, Codex or other AI tools?: The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.