> ## Documentation Index > Fetch the complete documentation index at: https://docs.stably.ai/llms.txt > Use this file to discover all available pages before exploring further. # Verify Your App with stably verify > Use stably verify to check that your application works correctly against a natural language description — no test files needed `stably verify` checks whether your application works correctly by describing what it should do in plain English. It launches an AI agent that navigates your app with a real browser, interacts with it, takes screenshots, and reports a structured **PASS / FAIL / INCONCLUSIVE** verdict. No test files are generated — it verifies and reports. ```bash theme={null} stably verify "the login form accepts email and password and redirects to /dashboard" ``` To run verification in a Stably-hosted browser, add `--browser=cloud` or set `STABLY_CLOUD_BROWSER=1`. See [Cloud Browsers for Stably CLI](/stably-cli/cloud-browser). ## How It Works ``` 1. You run: stably verify "users can add items to cart and see updated total" | 2. Interactive preflight (auto-detects your dev server and credentials) | 3. AI agent launches a browser and systematically verifies each requirement - Navigates to the app - Interacts with the UI (clicks, fills forms, scrolls) - Takes screenshots as evidence at each step - Checks DOM state, network responses, and visual output | 4. Agent reports a structured verdict: PASS, FAIL, or INCONCLUSIVE | 5. CLI prints a formatted summary and sets the exit code - Exit 0 = PASS - Exit 1 = FAIL - Exit 2 = INCONCLUSIVE ``` ## Prerequisites Install and initialize the Stably CLI in your project. ## Usage ```bash theme={null} # Verify a feature works stably verify "the login form accepts email and password and redirects to /dashboard" stably verify "the login form accepts email and password and redirects to /dashboard" --browser=cloud # Verify with a specific starting URL stably verify "the pricing page shows 3 tiers" --url https://localhost:3000/pricing # Set a budget cap (default: $5) stably verify "checkout flow completes successfully" --max-budget 10 ``` ### Options | Option | Description | | ------------------------ | ------------------------------------------------------------------------ | | `-u, --url ` | Starting URL to verify against (auto-detected from localhost if omitted) | | `--max-budget ` | Maximum budget in USD for the session (default: `5`) | | `--no-interactive` | Skip interactive preflight (for CI or agent use) | ### Exit Codes | Code | Verdict | Meaning | | ---- | ------------ | ------------------------------------------------------------------- | | `0` | PASS | All requirements in the prompt were verified | | `1` | FAIL | One or more requirements were not met | | `2` | INCONCLUSIVE | Could not determine pass or fail (app unreachable, auth wall, etc.) | ## Example Output ### PASS ``` VERIFICATION PASSED Prompt: "users can add items to cart and see updated total" Steps performed: 1. Navigated to /products 2. Clicked "Add to Cart" on first product -> cart badge updated to 1 3. Clicked "Add to Cart" on second product -> cart badge updated to 2 4. Opened cart -> shows 2 items with correct total of $45.98 Evidence: - Screenshot: products page with items visible - Screenshot: cart showing 2 items and $45.98 total - DOM check: .cart-total element contains "$45.98" ``` ### FAIL ``` VERIFICATION FAILED Prompt: "users can add items to cart and see updated total" Steps performed: 1. Navigated to /products 2. Clicked "Add to Cart" on first product -> cart badge updated to 1 3. Clicked "Add to Cart" on second product -> cart badge stayed at 1 Failure reason: Cart badge did not update after adding second item. Expected "2", saw "1". The cart total also only reflects one item ($22.99) instead of two. Evidence: - Screenshot: cart badge showing "1" after adding 2 items ``` ## Using stably verify with AI Agents `stably verify` is especially powerful when used inside AI coding agents. The agent writes code, then runs `stably verify` to check if the feature actually works — creating a build-then-verify iteration loop. ### Install the Skill Install the `stably-verify` skill to teach your agent how to use the command: ```bash theme={null} npx skills add https://github.com/stablyai/agent-skills --skill stably-verify ``` ### Agent Iteration Loop ``` Agent makes code changes ↓ stably verify "feature description" ↓ ┌─ PASS? → Done └─ FAIL? → Agent reads the verdict, fixes code, re-verifies ``` ### Example: Claude Code ``` You: Build a search bar that filters products by name Agent: I'll add the search component to the products page... [writes code] Let me verify this works. $ stably verify "the products page has a search bar that filters products by name as you type" --url http://localhost:3000/products VERIFICATION FAILED Steps performed: 1. Navigated to /products — 12 product cards visible 2. Found search input and typed "blue" 3. Product list did not change — still showing all 12 products Failure reason: Search input exists but typing does not filter. Agent: The search input isn't wired up to filter state. Let me fix that... [fixes code] $ stably verify "the products page has a search bar that filters products by name as you type" --url http://localhost:3000/products VERIFICATION PASSED Steps performed: 1. Navigated to /products — 12 product cards visible 2. Typed "blue" in search bar → 2 products shown 3. Cleared search → all 12 products restored Agent: Search bar is working correctly. ``` ### Example: Cursor / Windsurf Ask your agent naturally — the skill is triggered automatically: ``` "Use stably verify to check that the checkout flow works end to end" "Verify the dashboard shows the correct charts after my changes" ``` ### The Skill Prompt ```markdown theme={null} --- name: stably-verify description: | Verify that an application works correctly using stably verify. Use when an AI agent has made code changes and needs to validate the feature works in a real browser. Triggers on: "verify this works", "stably verify", "check if this works", "validate my changes", "verify my feature". license: MIT metadata: author: stably version: '1.0.0' --- # Verify App Behavior with stably verify Use `stably verify` to check that your application behaves correctly against a natural language description. The command launches an AI agent that navigates your app in a real browser, interacts with it, and reports a PASS/FAIL/INCONCLUSIVE verdict. No test files are generated. ## Pre-flight Always run `stably --version` first. If not found, install with `npm install -g stably` or use `npx stably`. ## Usage stably verify "description of expected behavior" stably verify "pricing page shows 3 tiers" --url http://localhost:3000/pricing stably verify "checkout completes" --max-budget 10 stably verify "login works" --no-interactive ## Options --url Starting URL (auto-detected if omitted) --max-budget Budget cap in USD (default: $5) --no-interactive Skip preflight prompts (for CI/agents) ## Exit Codes 0 = PASS (all requirements verified) 1 = FAIL (one or more requirements not met) 2 = INCONCLUSIVE (unable to determine — app not reachable, auth wall, etc.) ## Iteration Loop After making code changes, verify with stably verify. If the verdict is FAIL: 1. Read the failure reason and evidence from the output 2. Fix the application code based on the specific failure 3. Re-run stably verify with the same prompt 4. Repeat until PASS Important: stably verify does not create or modify files. It only observes and reports. Fix the code yourself based on its findings. ## Composing in Scripts stably verify "login works" && echo "Feature verified!" stably verify "checkout completes" ; code=$? if [ $code -eq 0 ]; then echo "PASS"; elif [ $code -eq 1 ]; then echo "FAIL"; else echo "INCONCLUSIVE"; fi ``` ## Combining with Other Stably Commands | Command | Purpose | When to Use | | --------------- | ----------------------------------------- | ---------------------------------------------- | | `stably verify` | Verify app behavior against a description | Quick feature validation, no test files needed | | `stably create` | Generate Playwright test files | Building lasting regression tests | | `stably test` | Run existing Playwright tests | Running your committed test suite | | `stably fix` | Auto-fix failing tests | Tests broke and need AI-powered repair | A typical workflow with an AI agent: Use `stably verify` to quickly check that your feature works as you build it. No test files to manage — just describe what should happen. Once the feature is stable, use `stably create` to generate Playwright test files for regression coverage. For future changes, run `stably test` to check the suite and `stably fix` to auto-repair failures. ## CI/CD Integration `stably verify` works in CI pipelines with `--no-interactive`: ```yaml theme={null} # .github/workflows/verify.yml - name: Verify feature run: npx stably verify "checkout flow completes successfully" --no-interactive env: STABLY_API_KEY: ${{ secrets.STABLY_API_KEY }} STABLY_PROJECT_ID: ${{ secrets.STABLY_PROJECT_ID }} ``` Use exit codes to gate deployments: ```bash theme={null} stably verify "all critical flows work" --no-interactive && deploy.sh ``` ## Next Steps Get set up with the Stably CLI Full command reference Generate Playwright test files with AI AI-powered test fixing