steel-developer

# Steel Developer ## Skill Boundary - Use this skill when the user wants code or implementation guidance they will run later. - Do not use this skill when the user wants the agent to browse, extract, screenshot, create a PDF, or fill a form now; use `steel-browser`. - Use `steel-session-debugging` when the main task is diagnosing a failed session. - Use `steel-reliability` when the main task is bot detection, proxy, CAPTCHA, identity, pacing, or login reliability mitigation. ## Route By Need Load the relevant reference before writing code: - CLI setup and local verification: `references/cli-setup.md` - TypeScript, JavaScript, Node.js, Playwright, Puppeteer, Stagehand: `references/typescript.md` - Python, Playwright Python, Browser Use: `references/python.md` - First-party APIs, exact docs/API/SDK lookup, browser tools, files, extensions, auth context, embeds, traces, mobile mode, multi-region: `references/apis.md` - Framework choice, Stagehand, Browser Use, typed agent frameworks, coding-agent integrations: `references/ecosystem.md` - Stale SDK/API patterns to avoid: `references/anti-patterns.md` - Computer-use loops: `references/computer-use.md` - Live and past session embeds: `references/live-embed.md` - Reliability boundary and handoff: `references/reliability-handoff.md` ## Non-Negotiables - Auth env var is `STEEL_API_KEY`. - Node examples import `Steel` from `steel-sdk`; SDK source is `steel-dev/steel-node`. - Node SDK constructor uses `steelAPIKey`. - Python SDK constructor uses `steel_api_key`. - Always release sessions in cleanup. - Construct the CDP URL explicitly as `wss://connect.steel.dev?apiKey=...&sessionId=...`. - Reuse the default browser context after connecting; do not create a new context unless the user explicitly needs isolation. - Keep target-site credentials out of prompts, code comments, page scripts, and logs. - For exact API fields or SDK method signatures, inspect the API reference, SDK docs, local installed types, or Steel docs via `curl -sSfL`. - Never use stale patterns listed in `references/anti-patterns.md`. ## Minimal Session Shape TypeScript: ```ts const steelAPIKey = process.env.STEEL_API_KEY; if (!steelAPIKey) throw new Error("STEEL_API_KEY is required"); const client = new Steel({ steelAPIKey }); const session = await client.sessions.create(); const cdpUrl = `wss://connect.steel.dev?apiKey=${steelAPIKey}&sessionId=${session.id}`; const browser = await chromium.connectOverCDP(cdpUrl); const context = browser.contexts()[0]; const page = context.pages()[0] ?? (await context.newPage()); try { await page.goto("https://example.com"); } finally { await browser.close(); await client.sessions.release(session.id); } ``` Python: ```python steel_api_key = os.environ["STEEL_API_KEY"] client = Steel(steel_api_key=steel_api_key) session = client.sessions.create() cdp_url = f"wss://connect.steel.dev?apiKey={steel_api_key}&sessionId={session.id}" browser = await playwright.chromium.connect_over_cdp(cdp_url) context = browser.contexts[0] page = context.pages[0] if context.pages else await context.new_page() try: await page.goto("https://example.com") finally: await browser.close() await playwright.stop() client.sessions.release(session.id) ``` ## Setup Verification ```bash steel --version steel login steel doctor --preflight steel skills doctor ``` ## Source-Of-Truth Links - API reference: https://steel.apidocumentation.com/api-reference - Node SDK/types: https://github.com/steel-dev/steel-node - Python SDK/types: https://github.com/steel-dev/steel-python - Docs index: `curl -sSfL https://docs.steel.dev/llms.txt` - Full docs bundle: `curl -sSfL https://docs.steel.dev/llms-full.txt` - Single docs page: `curl -sSfL https://docs.steel.dev/llms.mdx/<page-path>`