Record E2E Gif
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Record a Firefox performance profile with the firefox-devtools MCP.
Install Profile Capture
$ npx skills add mozilla-firefox/firefox --skill profile-capture -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install mozilla-firefox/firefox profile-capture --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/mozilla-firefox/firefox.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/profile-capture .claude/skills/profile-capture && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "profile-capture" agent skill from https://github.com/mozilla-firefox/firefox/tree/main/.agents/skills/profile-capture into .claude/skills/profile-capture/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "profile-capture", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/mozilla-firefox/firefox/tree/main/.agents/skills/profile-captureType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add mozilla-firefox/firefox --skill profile-capture -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install mozilla-firefox/firefox profile-capture --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mozilla-firefox/firefox.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/profile-capture .agents/skills/profile-capture && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "profile-capture" agent skill from https://github.com/mozilla-firefox/firefox/tree/main/.agents/skills/profile-capture into .agents/skills/profile-capture/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "profile-capture", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add mozilla-firefox/firefox --skill profile-capture -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install mozilla-firefox/firefox profile-capture --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mozilla-firefox/firefox.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/profile-capture .cursor/skills/profile-capture && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "profile-capture" agent skill from https://github.com/mozilla-firefox/firefox/tree/main/.agents/skills/profile-capture into .cursor/skills/profile-capture/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "profile-capture", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/mozilla-firefox/firefox.git --path .agents/skills/profile-capture--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add mozilla-firefox/firefox --skill profile-capture -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install mozilla-firefox/firefox profile-capture --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mozilla-firefox/firefox.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/profile-capture .gemini/skills/profile-capture && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "profile-capture" agent skill from https://github.com/mozilla-firefox/firefox/tree/main/.agents/skills/profile-capture into .gemini/skills/profile-capture/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "profile-capture", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install mozilla-firefox/firefox profile-captureInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add mozilla-firefox/firefox --skill profile-capture -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/mozilla-firefox/firefox.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/profile-capture .github/skills/profile-capture && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "profile-capture" agent skill from https://github.com/mozilla-firefox/firefox/tree/main/.agents/skills/profile-capture into .github/skills/profile-capture/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "profile-capture", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add mozilla-firefox/firefox --skill profile-capture -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install mozilla-firefox/firefox profile-capture --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mozilla-firefox/firefox.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/profile-capture .opencode/skills/profile-capture && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "profile-capture" agent skill from https://github.com/mozilla-firefox/firefox/tree/main/.agents/skills/profile-capture into .opencode/skills/profile-capture/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "profile-capture", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
profile-capture- GitHub stars
- 13k
- Token cost
- ~714 tokens
- SKILL.md length
- 291 words
- Files
- 1
- Skills in repo
- 7
- Repo updated
- First seen
- Licence
- Custom licence
At a glance
Record a Firefox performance profile with the firefox-devtools MCP.
- Diagnosing slowness in Firefox: startup
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
- A browser feature
- A reduced test case
What it does
Profile Capture is an agent skill from mozilla-firefox/firefox. Record a Firefox performance profile with the firefox-devtools MCP. Use when diagnosing slowness in Firefox: startup, page load, an interaction, a browser feature, a benchmark, a reduced test case, to obtain profiles - then analyze with profile-analysis.
Its SKILL.md is about 710 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Testing & QA, covering Test generation. It works with Chrome DevTools. The repository describes itself as: The official repository of Mozilla's Firefox web browser.
When your agent uses it
- Diagnosing slowness in Firefox: startup
- A browser feature
- A reduced test case
- Obtain profiles - then analyze with profile-analysis
Example prompts
- “/profile-capture”
Requirements
- Pre-approved tools (allowed-tools): mcp__firefox-devtools__*, Skill(profiler-analysis), Read, Grep, Glob
What it can do on your machine
Read from SKILL.md and the folder at commit 59c8a94. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves these tools, so the agent can use them without asking each time:
mcp__firefox-devtools__*Skill(profiler-analysis)ReadGrepGlob
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Profile Capture loads about 714 tokens when it runs. Until then it costs about 68 tokens; SKILL.md has 291 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
Its licence (Custom licence) doesn't allow us to republish the file, so here is its outline and opening line. It has 291 words (~714 tokens).
- name
- profile-capture
- allowed-tools
- mcp__firefox-devtools__*, Skill(profiler-analysis), Read, Grep, Glob
Files
Just SKILL.md in .agents/skills/profile-capture of mozilla-firefox/firefox.
Open the folder on GitHubat commit 59c8a94
Compare with similar skills
Profile Capture next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Profile Capture this skillmozilla-firefox/firefox | 13k | — | ~714 | Automated safety check: Pass | Custom licence | |
| Record E2E Giflablup/backend.ai-webui | 133 | — | ~907 | Automated safety check: Notes | LGPL-3.0 | |
| Write and Verify Playwright Testsappsmithorg/appsmith | 41k | — | ~2.9k | Automated safety check: Notes | Apache-2.0 | |
| Browser Testing with Chrome DevToolsaddyosmani/agent-skills | 103k | 4 repos | ~3.5k | Automated safety check: Warn | MIT | |
| Adk Verify Snippetsgoogle/adk-python | 22k | — | ~1.4k | Automated safety check: Pass | Apache-2.0 | |
| Engine E2Ewix/react-native-navigation | 13k | — | ~1.1k | Automated safety check: Pass | MIT |
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Related
Works with
Categories
Questions about Profile Capture
What does Profile Capture do?
Record a Firefox performance profile with the firefox-devtools MCP. Profile Capture is an agent skill from mozilla-firefox/firefox. Record a Firefox performance profile with the firefox-devtools MCP.
When should I use Profile Capture?
Profile Capture fits situations like: diagnosing slowness in Firefox: startup; A browser feature; A reduced test case; obtain profiles - then analyze with profile-analysis.
How do I install Profile Capture in Claude Code?
Run `npx skills add mozilla-firefox/firefox --skill profile-capture -a claude-code`. Or copy the skill folder (.agents/skills/profile-capture in mozilla-firefox/firefox) into .claude/skills/profile-capture in your project. Claude Code loads it when a task matches its description.
How do I install Profile Capture in Codex?
Run `npx skills add mozilla-firefox/firefox --skill profile-capture -a codex`. Or copy the skill folder (.agents/skills/profile-capture in mozilla-firefox/firefox) into .agents/skills/profile-capture in your project. Codex loads it when a task matches its description.
Can I use Profile Capture in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add mozilla-firefox/firefox --skill profile-capture -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/profile-capture, .gemini/skills/profile-capture, .github/skills/profile-capture and .opencode/skills/profile-capture in your project.
What does Profile Capture need to run?
SKILL.md names no scripts, command-line tools or credentials: Profile Capture is instructions for the agent only. Its frontmatter pre-approves these tools: mcp__firefox-devtools__*, Skill(profiler-analysis), Read, Grep, Glob.
Does Profile Capture access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Profile Capture safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Profile Capture use?
Profile Capture has a licence file (the repository's licence) that doesn't match a standard licence. Read it on GitHub before reusing the skill.
How many tokens does Profile Capture use?
About 714 tokens (SKILL.md is roughly 2.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Profile Capture?
Skills that share tags, products or a category with Profile Capture: Record E2E Gif (lablup/backend.ai-webui, 133 stars), Write and Verify Playwright Tests (appsmithorg/appsmith, 41k stars), Browser Testing with Chrome DevTools (addyosmani/agent-skills, 103k stars) and Adk Verify Snippets (google/adk-python, 22k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Profile Capture?
mozilla-firefox (a GitHub organization) maintains it in mozilla-firefox/firefox, which has 13,384 GitHub stars. The repository holds 7 skills in this directory. The repository was last updated on October 8, 2026.
Source: mozilla-firefox/firefox on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.