Retrieve a web page and return its content as markdown (default), text, HTML, a JSON envelope, or a printed PDF. Handles the fetch vs. browser decision, charset decoding, and PDF-to-text for you. Optionally extract structured data with CSS selectors (`extract`) or `autoparse` (a natural-language `ai_extract` is coming soon), return discovered `links`, take a `screenshot`, or scope the DOM with `include_tags`/`exclude_tags`. Each successful call is billed in credits (a failure costs 0). Results are cached by default, and a cache hit is billed like the fetch that stored it (the cache saves time, not credits); set `cache=false` for time-sensitive pages. With the defaults it only reads the page. A `method` other than GET, HEAD or OPTIONS, and the `actions` that click, fill or run scripts on the page, can change state on the target site: set them only when the user asks for that. For markdown, text and HTML it returns `{ content }`. With `format: "json"`, or when `extract`, `ai_extract`, `autoparse`, `links`, `screenshot` or `network_capture` is set, it returns the JSON envelope: `content`, the site's `status`, `credits`, `engine` (the rendering tier: `fetch`, `js` or `browser`), `warnings` and `data` for extraction. Screenshots come back as image content blocks; each `screenshots` entry in the JSON keeps its metadata and says which block holds it. A PDF comes back as a resource content block, with its size, the rendering tier and the credits in the JSON.
