Start a recording session: launches a themed headless browser and begins capturing video. Returns the session config and the output directory. One session at a time — studio_finish or studio_cancel ends it. Set theme to the PRODUCT'S brand (bg = its app background — wrong bg causes visible flashes on page loads); use storage_state_path (a Playwright storageState JSON) to record logged-in areas without sharing credentials; list chat widgets / dev overlays / consent banners in hide_selectors so they never appear on tape.

Navigate to a URL behind a designed transition card (eyebrow + big title on the theme background) — the viewer never sees a loading flash or half-hydrated page. Use for the opening shot AND every surface change; give each a short title so the cut reads as a chapter. Waits for real content (network settle + optional wait_for selector + skeleton loaders cleared) before lifting the card.

Glide the visible cursor to a target and click it, slow enough to read as a deliberate action on camera. Use for every button / link / menu interaction in the walkthrough. Precondition: the target must be on screen — studio_goto or studio_scroll to it first if it isn't. Prefer a stable CSS selector; fall back to visible text. After clicking it waits for the page to settle and re-applies the theme overlays, so the next beat is on a hydrated page. Returns 'clicked <target>', or errors 'target not visible' — then take a studio_screenshot and pick a better target.

Glide to an input and type text at a human pace (keystroke by keystroke — it reads as real usage, not a paste). Use realistic demo content; whatever you type is on tape.

Cubic-eased scroll to an absolute Y offset or until a target element is in view — never a jump cut. Use between story beats to bring the next area on camera. Side effect: changes only the page scroll position (no click, no navigation). Pass exactly ONE of to_y or to_target. Returns 'scrolled' on completion. To reveal an off-screen element before studio_click or studio_highlight, scroll to it first.

Show (or replace) the bottom-left storyline caption — an eyebrow kicker plus one sentence that narrates the current beat. Keep it under ~12 words and leave it up 2–4s (studio_hold) so it reads. Pass clear=true to fade it out before a scene change. The caption_text is ALSO recorded as the voice-over script: if you call studio_finish with voiceover:true it's spoken aloud (locally) timed to this moment — write captions as speakable sentences. Set no_voice:true for a caption you want on screen but NOT narrated.