Cloudflare Browser Rendering

Overview

Use this skill to bridge the gap between lightweight web_fetch and full interactive browser automation.

Routing rule:

• Use web_fetch for simple static pages and quick reads.
• Use this skill when content depends on JavaScript rendering or when you need to crawl many related pages.
• Use browser when the task requires interaction such as login, clicking, typing, or manual flow control.

Quick decision guide

• Single page, static, fastest path matters -> web_fetch
• Single page, JS-heavy, want clean markdown -> /markdown
• Whole docs/blog/help center crawl -> /crawl
• Needs login/UI actions -> browser

If uncertain, start with web_fetch. Escalate to /markdown if the page is incomplete or empty. Escalate to /crawl only when multiple pages are needed.

Read references/decision-guide.md for routing details and references/*.md for endpoint notes.

Prerequisites

Expect these environment variables to be available before running the scripts:

• CLOUDFLARE_API_TOKEN
• CLOUDFLARE_ACCOUNT_ID

The token needs Browser Rendering Write for /markdown and crawl creation. Reading crawl results can use Browser Rendering Read or Write.

Single-page extraction with /markdown

Use scripts/cf_markdown.py.

Examples:

python3 scripts/cf_markdown.py --url https://example.com
python3 scripts/cf_markdown.py --url https://example.com --wait-until networkidle0
python3 scripts/cf_markdown.py --url https://example.com --wait-until networkidle0 --timeout-ms 60000
python3 scripts/cf_markdown.py --url https://example.com --cache-ttl 0 --json
python3 scripts/cf_markdown.py --html '<div>Hello</div>'
python3 scripts/cf_markdown.py --url https://example.com --user-agent 'Mozilla/5.0 ...'
python3 scripts/cf_markdown.py --url https://example.com --cookies-json '[{"name":"session","value":"abc","domain":"example.com"}]'
python3 scripts/cf_markdown.py --url https://example.com --authenticate-json '{"username":"u","password":"p"}'
python3 scripts/cf_markdown.py --url https://example.com --reject-request-pattern-json '["/^.*\\\\.(css)$/"]'

Guidelines:

• Prefer --wait-until networkidle0 or networkidle2 for SPA/JS-heavy pages.
• If a JS-heavy page times out, first raise --timeout-ms (for example 60000), then consider falling back to domcontentloaded if full idle waiting is too slow.
• Use --cache-ttl 0 when freshness matters more than speed.
• Use --json when you want full API output for debugging.
• Use raw JSON flags when you need advanced body fields without patching the script.

Multi-page crawling with /crawl

Use scripts/cf_crawl.py.

Examples:

python3 scripts/cf_crawl.py start --url https://developers.cloudflare.com/workers/ --depth 2 --limit 20 --format markdown
python3 scripts/cf_crawl.py wait --job-id <job_id> --poll-seconds 5
python3 scripts/cf_crawl.py results --job-id <job_id> --limit 20 --status completed
python3 scripts/cf_crawl.py run --url https://developers.cloudflare.com/workers/ --depth 2 --limit 20 --format markdown --wait
python3 scripts/cf_crawl.py run --url https://developers.cloudflare.com/workers/ --depth 2 --limit 20 --format markdown --wait --fetch-results --results-status completed --out-json out/crawl.json --out-markdown out/crawl.md
python3 scripts/cf_crawl.py start --url https://example.com --source links --goto-options-json '{"timeout":30000}'

Guidelines:

• Keep initial crawls small: low depth and modest limit.
• Use run --wait for one-shot jobs.
• Use run --wait --fetch-results when you want a full one-command workflow.
• Use start + wait + results when you want more control.
• Poll lightly; do not tight-loop.
• Prefer markdown format for downstream summarization or embeddings.
• Use --out-json and --out-markdown for large outputs instead of dumping everything into chat.

Output handling

For large crawls:

• First inspect summary fields: job status, total, finished, browser seconds used.
• Then fetch filtered results, usually status=completed.
• Avoid dumping huge markdown blobs into chat; summarize and point to saved output if needed.

Failure and fallback rules

• If /markdown returns incomplete content, retry with --wait-until networkidle0.
• If /crawl is overkill for the task, fall back to /markdown on key URLs.
• If the site requires interaction or login, stop using this skill and switch to browser.
• If the API is unavailable or credentials are missing, report that clearly and fall back to web_fetch when possible.

Resources

• scripts/cf_markdown.py - rendered single-page Markdown extraction
• scripts/cf_crawl.py - async crawl job helper
• references/decision-guide.md - routing and fallback guidance
• references/markdown-endpoint.md - focused notes on /markdown
• references/crawl-endpoint.md - focused notes on /crawl