burn-after-login

name	burn-after-login
description	Create dev-only auth shortcuts so AI browser automation agents can authenticate instantly. Analyzes your auth system, creates guarded endpoints/scripts, detects your browser automation tools, and updates agent instructions. Use when setting up dev authentication for browser automation, or when agents struggle with login forms. Self-destructs after completion.
license	MIT
metadata	{"author":"pbakaus","version":"1.0"}
compatibility	Requires an existing authentication system and dev/local mode detection.

Burn After Login

Your mission, should you choose to accept it, is to create dev-only auth shortcuts so AI browser agents can authenticate instantly. This skill will self-destruct after completion.

Follow these phases in order. If a phase has an EXIT CONDITION that triggers, stop immediately and report the issue — do NOT continue to later phases.

---

Phase 1: Environment Validation

Verify this codebase has:

1. A way to detect development/local mode. Look for:

   • Environment variables: NODE_ENV, RAILS_ENV, FLASK_ENV, APP_ENV, DEBUG, ENVIRONMENT, etc.
   • Config files that distinguish dev from prod
   • Build flags or conditional compilation

2. An existing authentication system. Look for:

   • Auth-related directories: auth/, authentication/, identity/
   • Auth libraries in dependencies (check package.json, requirements.txt, Gemfile, go.mod, Cargo.toml, etc.)
   • Middleware or decorators that check auth
   • Login routes or handlers

EXIT CONDITIONS:

• If no dev mode detection exists: Stop and say "Could not find a way to detect development mode. Add environment-based detection first to ensure auth shortcuts are never exposed in production."
• If no auth system exists: Stop and say "No authentication system found. Set up authentication first."

---

Phase 2: Find Development Credentials

Search for existing dev/test credentials in:

• Seed/fixture files: seed.*, fixtures/, test-data/, mock/
• Scripts directory for user management tools
• Database migrations or seeders
• Documentation mentioning test accounts (README, CLAUDE.md, etc.)
• Environment files (.env.development, .env.local, .env.example)

Search patterns: username, password, testuser, demo, admin@, test@, seed, fixture

EXIT CONDITION:

• If no credentials found: Stop and say "No development credentials found. Create test users first (via seed script, admin panel, or auth provider dashboard), then run this again."

Document what you find — list the credentials with their roles.

---

Phase 3: Analyze Authentication

Discover:

1. How auth works in this codebase:

   • Token-based (JWT, API keys, Bearer tokens)
   • Session/cookie-based
   • Both (common in apps with API + web frontend)

2. What auth library/framework is used:

   • Identify from dependencies and imports
   • Understand how to programmatically authenticate a user
   • Understand how sessions/tokens are created and validated

3. What apps/services exist:

   • Web frontends (any framework)
   • Admin interfaces
   • API servers
   • List each with its path and auth pattern

---

Phase 4: User Selection

Ask the user which apps/services should have dev auth shortcuts.

If a tool to ask the user is unavailable, create shortcuts for all discovered apps.

---

Phase 5: Create Shortcuts

Create authentication shortcuts appropriate for the codebase's language, framework, and auth system.

For token-based auth — Token Generator

Create a script that:

• Accepts credentials (with sensible dev defaults)
• Calls the existing auth system to get a token
• Outputs only the token to stdout (for easy scripting)
• Example usage: TOKEN=$(./scripts/get-token) && curl -H "Authorization: Bearer $TOKEN" http://localhost:8000/api/...

For cookie/session auth — Dev Login Endpoint

Create an endpoint that:

• Accepts credentials via query params or JSON body
• Calls the existing auth system
• Sets session cookies
• Returns 404 in production (not an error — completely hidden)
• Example usage: open "http://localhost:3000/dev-login?user=demo&pass=demo"

Guidelines

1. Follow existing patterns — Match the codebase's style, conventions, and directory structure
2. Use the existing auth system — Don't reinvent; call the same auth functions the app uses
3. Guard with dev-only checks — The shortcut MUST refuse to work in production
4. Keep it simple — Minimal code that does one thing

Security Requirements

• Check for development mode BEFORE doing anything
• Return 404 or equivalent in production (not an error message that reveals the endpoint exists)
• Never log credentials
• Consider also checking for localhost/127.0.0.1 if appropriate

Reference Implementations

Use these for inspiration only. Adapt to the actual stack and auth system in use.

Node.js Token Generator

// scripts/get-token.ts
async function main() {
  const [user, pass] = process.argv.slice(2);
  const { token } = await yourAuthLib.signIn(
    user || '[e-mail]',
    pass || 'demo'
  );
  console.log(token);
}
main();

Next.js Dev Login

export async function GET(req: Request) {
  if (process.env.NODE_ENV !== 'development') {
    return new Response('Not found', { status: 404 });
  }
  const url = new URL(req.url);
  await yourAuth.signIn(
    url.searchParams.get('email'),
    url.searchParams.get('password')
  );
  return Response.json({ ok: true });
}

Django Dev Login

from django.conf import settings
from django.http import Http404, JsonResponse
from django.contrib.auth import authenticate, login

def dev_login(request):
    if not settings.DEBUG:
        raise Http404()
    user = authenticate(
        username=request.GET.get('user'),
        password=request.GET.get('pass')
    )
    if user:
        login(request, user)
        return JsonResponse({'ok': True})
    return JsonResponse({'error': 'Invalid'}, status=401)

Rails Dev Login

class DevSessionsController < ApplicationController
  skip_before_action :verify_authenticity_token

  def create
    raise ActionController::RoutingError, 'Not Found' unless Rails.env.development?
    user = User.find_by(email: params[:email])
    if user&.authenticate(params[:password])
      session[:user_id] = user.id
      render json: { ok: true }
    else
      render json: { error: 'Invalid' }, status: 401
    end
  end
end

Flask Dev Login

@app.route('/dev-login')
def dev_login():
    if not current_app.debug:
        abort(404)
    user = authenticate(
        request.args.get('email'),
        request.args.get('password')
    )
    if user:
        session['user_id'] = user.id
        return jsonify(ok=True)
    return jsonify(error='Invalid'), 401

Go Dev Login

func DevLogin(w http.ResponseWriter, r *http.Request) {
    if os.Getenv("ENV") != "development" {
        http.NotFound(w, r)
        return
    }
    user, err := auth.Authenticate(
        r.URL.Query().Get("email"),
        r.URL.Query().Get("password"),
    )
    if err != nil {
        http.Error(w, "Unauthorized", 401)
        return
    }
    session.Set(r, w, user)
    json.NewEncoder(w).Encode(map[string]bool{"ok": true})
}

---

Phase 6: Detect Browser Automation Tools

Scan the project for browser automation tools that are configured or in use. Check:

1. MCP server configurations — Look in .claude/settings.json, mcp.json, .cursor/mcp.json, or similar for:

   • claude-in-chrome or chrome-extension
   • playwright or @anthropic/mcp-playwright or @anthropic-ai/mcp-playwright
   • chrome-devtools or devtools-mcp
   • browserbase or stagehand

2. Dependencies — Check package.json, requirements.txt, Gemfile, go.mod, etc. for:

   • playwright, @playwright/test
   • puppeteer, puppeteer-core
   • selenium, selenium-webdriver
   • cypress
   • @browserbasehq/stagehand
   • agent-browser

3. Config files — Look for:

   • playwright.config.ts, playwright.config.js
   • cypress.config.ts, cypress.config.js
   • .puppeteerrc.js

4. Existing agent instructions — Scan CLAUDE.md, AGENTS.md, GEMINI.md, CURSOR.md, COPILOT.md, .github/copilot-instructions.md, README.md, and files in .claude/, .cursor/, .agents/, .windsurf/ for any mentions of browser automation, testing, or auth flows.

Record everything you find — you'll need it for the next phase.

---

Phase 7: Update Agent Instructions & Documentation

Based on what you found in Phase 6, update or create documentation so that AI agents using browser automation know about the dev auth shortcuts.

For each detected browser automation tool, add specific usage instructions:

Claude in Chrome / Chrome Extension MCP:

To authenticate in the browser, navigate to:
http://localhost:PORT/dev-login?email=EMAIL&password=PASSWORD
Then proceed to the authenticated page.

Playwright / Playwright MCP:

To authenticate before testing:
await page.goto('http://localhost:PORT/dev-login?email=EMAIL&password=PASSWORD');
// Session cookies are now set, proceed with authenticated actions
await page.goto('http://localhost:PORT/dashboard');

Token-based (for API testing with any tool):

To get an auth token for API requests:
TOKEN=$(./scripts/get-token EMAIL PASSWORD)
Use header: Authorization: Bearer $TOKEN

Where to add documentation:

• If CLAUDE.md exists — add a "Dev Authentication" section
• If AGENTS.md exists — add a "Dev Authentication" section
• If CURSOR.md exists — add equivalent instructions
• If GEMINI.md exists — add equivalent instructions
• If COPILOT.md or .github/copilot-instructions.md exists — add equivalent instructions
• If .windsurf/ config exists — add equivalent instructions
• If none of these exist — create an AGENTS.md with the auth instructions

Always match the existing style and formatting of each file you modify.

Documentation must include:

1. What dev auth shortcuts are available (endpoints and/or scripts)
2. The test credentials and their roles
3. Tool-specific usage examples (based on what was detected)
4. A note that these only work in development mode

---

Phase 8: Summary

Present a clear report:

• What was created (with file paths)
• How to use each shortcut (with copy-pasteable commands)
• Which agent instruction files were updated
• Security measures in place
• Test credentials reference

---

Phase 9: Self-Destruct

After presenting the summary, say:

Mission complete. All dev auth shortcuts are in place and your agent instructions have been updated.

This skill has served its purpose. Like any good secret agent tool, it should leave no trace. Want me to self-destruct? (y/n)

If the user agrees:

1. Check for skills.lock in the project root or common locations. If it exists and contains burn-after-login, the skill was installed via npx skills. Run:

   npx skills remove burn-after-login
   

   This handles all cleanup. Done.

2. If no skills.lock found, manually clean up by deleting the skill directory from all locations where it may exist:

   • .agents/skills/burn-after-login/
   • .claude/skills/burn-after-login/
   • .claude/commands/burn-after-login.md
   • .cursor/skills/burn-after-login/
   • .windsurf/skills/burn-after-login/
   • Any symlinks pointing to the above

3. After cleanup, say:

   This skill will self-destruct in 3... 2... 1...

   burn-after-login has been removed. Your dev auth shortcuts remain intact. Good luck out there, agent.

If the user declines:

Understood. The skill remains installed if you need to run it again. You can remove it anytime with npx skills remove burn-after-login.