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Fagun - One MCP server that gives any AI tool a real browser to click, crawl, and find real bugs — functional, security,
Give any AI a browser to use your product like real customers, run full UAT, hunt real bugs, and tell you if it's ready to ship.
Fagun is a single tool that plugs into Claude, Cursor, Codex, Antigravity, Windsurf,
Cline, or VS Code. Once it's set up, you just type fagun (or /fagun) and your
AI can open a real browser and:
You set it up once. It works in every AI tool. Chrome installs itself.
🌐 Website: https://mejbaurbahar.github.io/fagun/ · 📦 PyPI: https://pypi.org/project/fagun/
Fagun does not require users to bring a Groq, OpenAI, Anthropic, Gemini, or other model API key. It runs inside the AI app the user already chose. Claude, Codex, Antigravity, Cursor, Windsurf, or a local MCP-capable model does the reasoning; Fagun supplies the browser, QA, security, evidence, and report tools.
For plain-English browser tests, ask your AI:
fagun https://example.com: search for "pricing" and verify results load
The AI should call autoqa_prompt(url, goal), create a small plan with its own
model, then execute it with Fagun tools like navigate, click, fill,
screenshot, get_console, and get_network. Fagun should open Chrome through
Chrome DevTools MCP automatically when the AI client exposes it, using the user's
default Chrome session. It should only fall back to Fagun's browser if Chrome MCP
is unavailable or attach fails, and the fallback should be shown in the report.
Fagun remains the main tool and report brand, but it should call installed
supporting MCPs when useful. Jam MCP should be used when available for each
important Interactive Test Flow step and for reproducible bugs, attaching a
screenshot or screen recording with console/network context. At the end it should
call autoqa_write_html_report to create a branded HTML report under
./reports/, then open the returned Report URL with Chrome DevTools MCP/default
Chrome. The report includes project name, collected target URL, opened website
logo, full prompt, Fagun Tools title, Interactive Test Flow steps, per-step
evidence, Jam links/recordings, bugs, and fixes.
Supporting MCPs are routed by job:
Phased power workflow:
autoqa_write_html_report stores structured JSON run
records under reports/runs/; inspect them with autoqa_list_runs(limit).autoqa_replay_prompt(run_ref) turns any
stored run into a replay prompt for regression testing.autoqa_compare_runs(before_ref, after_ref)
shows fixed, still-open, and new findings.autoqa_power_plan(url, goal), then use
evidence timeline fields, list_test_data,
a11y_audit + keyboard_walk, map_api, deep_test(include_api_map=true),
auth/session tools, and optional LangGraph orchestration.Issue-tracker export is intentionally not included in this workflow.
Recommended, no Python needed:
uvx fagun init
Already installed but still seeing old output? Force the newest release:
uvx --upgrade --reinstall fagun init
If you prefer pip/Python:
pip install --upgrade fagun
fagun init
That's the whole install. fagun init installs the Chrome engine and auto-detects
every AI tool on your machine (Claude Code, Claude Desktop, Cursor, Codex, Windsurf)
and registers the fagun browser tools, Chrome DevTools MCP, + the /fagun
skill in each one. It also opens chrome://inspect/#remote-debugging so Chrome
can show the official Allow remote debugging? popup when Fagun attaches to
your signed-in default Chrome session.
The setup output is a modern CLI dashboard: task, progress table, configuration
files, final summary, and next commands. Paths are shortened with ~ so users can
see exactly what changed without reading noisy logs.
If your terminal still says Fagun init — setting up everything…, you are running
an old cached package. Refresh it with uvx --upgrade --reinstall fagun init or
pip install --upgrade fagun && fagun init.
Then restart your AI tool and type fagun — followed by what you want tested.
After setup, use Fagun inside your AI tool:
fagun deep test https://example.com
fagun security scan https://example.com
fagun check links on https://example.com
fagun test the signup form on https://example.com
Paste-prompt (let the AI do it):
Install and set up fagun for me: install
uvif missing, then runuvx fagun init. Follow https://github.com/mejbaurbahar/fagun/blob/main/install.md if anything fails.
Claude Code plugin:
/plugin marketplace add mejbaurbahar/fagun
/plugin install fagun@fagun
Target one tool:
uvx fagun install claude-code # or: cursor | claude | vscode
uv yet? (one line, no Python needed)macOS / Linux: curl -LsSf https://astral.sh/uv/install.sh | sh
Windows: powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | iex"
Then restart your terminal.
Step 1 — install uv (it brings its own Python, so nothing else is required):
macOS / Linux:
curl -LsSf https://astral.sh/uv/install.sh | sh
Windows (PowerShell):
powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | iex"
⚠️ Restart your terminal after this so
uvis on your PATH. (macOS/Linux: or runsource $HOME/.local/bin/envin the current shell.)
Step 2 — set up Fagun:
uvx fagun init # installs browser + wires AI tools + Chrome DevTools MCP + /fagun skill
That's it. Restart your AI tool, type fagun, and go.
Already have
pip/Python? Runpip install --upgrade fagun && fagun init.
💡 Don't want to think about config? Just tell your AI: "Install and set up fagun for me — follow https://github.com/mejbaurbahar/fagun/blob/main/install.md" and it does everything above for you.
Every tool gets two MCP servers:
uvx fagun init writes both automatically. Manual config:
| Tool | How |
|---|---|
| Claude Code | claude mcp add fagun -- uvx fagun and claude mcp add chrome-devtools -- npx -y chrome-devtools-mcp@latest --auto-connect --no-usage-statistics |
| Claude Desktop | add the JSON below to claude_desktop_config.json |
| Cursor | uvx fagun install cursor (writes ~/.cursor/mcp.json) |
| VS Code (Copilot) | uvx fagun install vscode (writes .vscode/mcp.json) |
| Windsurf / Cline / Antigravity | paste the JSON below into their MCP settings |
| Codex CLI | add the TOML below to ~/.codex/config.toml |
// Claude Desktop / Cursor / Windsurf / Cline / Antigravity
{
"mcpServers": {
"fagun": { "command": "uvx", "args": ["fagun"] },
"chrome-devtools": {
"command": "npx",
"args": ["-y", "chrome-devtools-mcp@latest", "--auto-connect", "--no-usage-statistics"],
"env": {
"CHROME_DEVTOOLS_MCP_NO_USAGE_STATISTICS": "1",
"CHROME_DEVTOOLS_MCP_NO_UPDATE_CHECKS": "1"
}
}
}
}
# Codex — ~/.codex/config.toml
[mcp_servers.fagun]
command = "uvx"
args = ["fagun"]
[mcp_servers.chrome-devtools]
command = "npx"
args = ["-y", "chrome-devtools-mcp@latest", "--auto-connect", "--no-usage-statistics"]
env = { CHROME_DEVTOOLS_MCP_NO_USAGE_STATISTICS = "1", CHROME_DEVTOOLS_MCP_NO_UPDATE_CHECKS = "1" }
startup_timeout_ms = 20_000
The -y flag prevents npx from asking the user to confirm package download.
--auto-connect makes Chrome DevTools MCP attach to the user's running Chrome.
On first setup, Fagun opens chrome://inspect/#remote-debugging; turn on remote
debugging there, then click Allow when Chrome shows the permission popup.
Users do not need to run fagun connect to my Chrome first; fagun deep test <url>
should auto-use Chrome DevTools MCP when the AI client exposes it.
If the target is still logged out, Fagun checks auth_status: the user can log in
manually in Chrome, or provide authorized test credentials for login_with_credentials.
Passwords are masked in output and the resulting session can be saved for future
authenticated tests.
Fagun opts out of Chrome DevTools MCP usage statistics and update-check noise in
generated configs.
Restart the tool after adding it. Then type fagun.
▶️ Live animated demo (macOS / Windows / Linux): https://mejbaurbahar.github.io/fagun/#see-it-in-action
Setup + first bug on each OS:
macOS / Linux
curl -LsSf https://astral.sh/uv/install.sh | sh # get uv (once)
uvx fagun init # browser + all AI tools + skill
# then, inside your AI tool, type:
# fagun deep test https://example.com
Windows (PowerShell)
powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | iex" # get uv (once)
uvx fagun init # browser + all AI tools + skill
# then, inside your AI tool, type:
# fagun audit https://example.com
That's the whole flow: install uv → uvx fagun init → type fagun <task> in any AI tool.
Just talk to your AI in plain English:
fagun → shows the menu and starts upgo to example.com and take a screenshotrun QA on https://example.comdeep test https://example.com and save the report to ./report.mdcheck for broken links on https://example.comtest the forms on the signup pageare there any console errors? · any failed network requests?log in with test@x.com / password123, then check the dashboard/fagun bug hunterFagun ships with a skill that turns your AI into a methodical QA tester. It sweeps the full product-readiness surface and only reports bugs it can actually reproduce (no guessing):
| # | Checks for |
|---|---|
| 1 | Functional — broken journeys, buttons/links that lie |
| 2 | JavaScript errors — crashes, console errors on load & on click |
| 3 | Network / API — 4xx/5xx, failed calls, mixed content |
| 4 | Forms — missing validation, insecure submission, no labels |
| 5 | Auth / sessions — login errors, leaks, access control |
| 6 | Accessibility — missing alt text, labels, keyboard traps |
| 7 | Performance — slow loads, heavy resources |
| 8 | Visual / responsive — layout breakage, overflow, cut-off text |
| 9 | Security — missing CSP/HSTS, exposed versions, secrets in code |
| 10 | SEO / discoverability — titles, H1s, metadata, crawlability |
| 11 | UX / product clarity — confusing flows, blockers, weak empty states |
| 12 | Business logic — wrong outcomes, bad totals, broken lead/checkout paths |
| 13 | Mobile / desktop parity — breakpoint and device-specific failures |
| 14 | Keyboard / screen-reader use — focus order, traps, labels, contrast |
| 15 | Headers / CORS / CSP — browser security posture and misconfigurations |
| 16 | Edge cases — reloads, back button, huge inputs, unicode, offline-ish states |
| 17 | AI/security orchestration — optional safe tool planning for deeper authorized tests |
Every finding comes with steps to reproduce, what was observed, and the impact.
Browser tools normally flood your AI's context with huge JSON blobs and full network/console dumps — burning tokens fast. Fagun is built to be token-lean:
FAGUN_TERSE=0 for full JSON, or pass
verbose=true to any tool for one call.deep_test crawls + checks console, network, forms,
headers, a11y, perf across the whole site in a single tool call, instead of
many manual navigate + get_console + get_network round-trips.+N more marker; duplicate findings are collapsed.report_path and raw detail is
written there; the final chat answer still shows the full user-facing result:
verdict, all findings, evidence, fixes, coverage, and report link.💡 Cheapest workflow:
deep test <url> and save the report to ./report.md→ one call, full Fagun answer in chat, raw evidence/report on disk.
Set these as environment variables if you need them:
| Variable | Default | What it does |
|---|---|---|
FAGUN_HEADLESS | 1 | Set to 0 to watch the browser work |
FAGUN_BROWSER | chromium | Use firefox or webkit instead |
FAGUN_CDP_URL | — | Attach to your own open Chrome, e.g. http://127.0.0.1:9222 |
FAGUN_TERSE | 1 | Compact token-lean output. Set 0 for full JSON or mini for extra-short summaries. |
FAGUN_FINDING_CAP | 40 | Max findings shown per page in chat output. Full report still goes to disk. |
FAGUN_PAGE_CAP | 12 | Max pages shown in multi-page chat summaries. |
FAGUN_DETAIL_CHARS | 100 | Max chars per finding detail in terse output. |
FAGUN_URL_CHARS | 60 | Max chars per URL in terse output. |
For the lowest-token workflow, use:
FAGUN_TERSE=mini
Then ask: deep test <url> and save the report to ./fagun-report.html. The chat
gets a tiny summary; the full evidence stays in the report file.
Fagun ships a reusable response contract so Claude, Codex, Cursor, Gemini, Qwen, DeepSeek, or a custom wrapper can show results in the same style:
fagun_style_prompt — copy into system/custom instructions for Markdown output.fagun_style_prompt(mode="json") — tells the model to return structured JSON.fagun_style_schema — JSON schema for a frontend renderer with cards/panels.fagun_render_response — converts JSON or plain text into Fagun-style Markdown.Default sections: Executive Summary, Problem, Analysis, Solution, Implementation, Test Cases, Edge Cases, Risks, Production Impact, API Validation, Performance, Jira Ticket, and Final Recommendation.
For deeper authorized bug-hunting workflows, Fagun now includes an AI security engineer prompt and an external-tool catalog. It does not blindly run exploit tools; it plans adapters, explains when each tool fits, and keeps execution scope-gated:
fagun_security_prompt — improved enterprise prompt for authorized security testing.list_external_security_tools — catalog for Loxs, Skill Security Scanner,
Shannon, Lonkero, recon-skills, payload corpora, RFC822 Email Validator,
LostFuzzer, img-payloads, customBsqli, BeeXSS, TimeVault, and NextSploit.recommend_security_tools — picks the smallest relevant tool plan from the
target profile and goal, then tells the AI how to validate and report evidence.Use it for attack-graph planning, tool selection, deduplication, validation, remediation, and regression tests. Active probes still require authorization.
recon-skills is treated as a read-only methodology pack first: Fagun can use it
to pick relevant recon, red-team, sector, chain, SAML, Docker, WordPress, CORS,
XMLRPC, JS-secret, metrics, and API-flow checklists, then translate those into
authorized Fagun-safe test plans.
security scan <url> runs the bug classes hunters get paid for — non-destructive,
GET/HEAD only, no attacks on third parties:
/.git, /.env, /.aws/credentials, backups, actuator)⚠️ Only scan sites you own or are authorized to test.
--auto-connect during normal deep tests, so it can
reuse your already-signed-in default Chrome after you allow remote debugging.
Great for testing behind a login without giving credentials to the AI.login-required and asks for manual
login or authorized test credentials. login_with_credentials records the
login action trace but prints the password only as [hidden].connect to my Chrome is only a troubleshooting fallback that launches a
dedicated debuggable Chrome profile and attaches to it.browser_exec → when no built-in tool fits, the AI writes Python against the live
page (full Playwright). save_helper persists what works, so Fagun gets smarter
every run.fagun_start · product_map · auth_status · login_with_credentials ·
open_browser · navigate · click · fill · press_key ·
screenshot · evaluate_js · get_console · get_network · crawl · run_qa ·
check_links · test_forms · fuzz_forms · list_test_data · perf_audit ·
a11y_audit · security_headers · security_scan · advanced_security ·
deep_test · full_qa_sweep · write_report · browser_exec · save_helper ·
list_helpers · load_helper · connect_chrome · fagun_security_prompt ·
list_external_security_tools · recommend_security_tools · close_browser
What's new in v0.7.0 — deeper, smarter, evidence-backed:
fuzz_forms — actively fills every form field with a labelled test-data
catalog (valid / invalid / negative / empty / whitespace / special character /
unicode / boundary / out-of-box / injection) and reads the browser's real
Constraint-Validation verdict. Reports include a field-by-field scenario matrix
and screenshots for failed cases. A validation gap is reported only when the
browser itself accepted a value it should have rejected.perf_audit — real Core Web Vitals (LCP, CLS, TBT, FCP, TTFB) from the
browser's Performance APIs + a Lighthouse-comparable 0-100 score. No estimates.a11y_audit — deep WCAG 2.1 checks incl. real computed color-contrast.advanced_security / bigger security_scan — CSP quality, clickjacking,
risky HTTP methods, mixed content, missing SRI, sensitive-page caching, host-
header injection, CRLF, path-traversal/LFI, SSTI, command-injection, GraphQL
introspection, error/stack-trace disclosure, sensitive-data-in-URL.git clone https://github.com/mejbaurbahar/fagun && cd fagun
pip install -e .
python -m playwright install chromium
python -m fagun # runs the MCP server on stdio
Release (maintainer): publishing is automatic via GitHub Actions +
PyPI Trusted Publishing. Bump the
version in pyproject.toml and src/fagun/__init__.py, then:
git tag v0.3.0 && git push origin v0.3.0
MIT © Mejbaur Bahar Fagun
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