removing-and-replacing-backgroundslisted

# Removing & Replacing Backgrounds The capability is a composable **cutout asset** — one tool produces an alpha-matted file; everything after that (replacement, transplant, export) is libi's EXISTING compositing. Never write custom compositing code for this. > **Engine install:** if `libi.remove_background` returns > `dependency_not_ready` / `tracking_engine_not_installed`, follow the > libi-tracking install plan (`libi.get_install_plan` with > `mcpId: "libi-tracking"`, then — after disclosing ~10–20 min / ~2 GB on the > user's machine and getting approval — `libi.install_tracking_engine`, then > `libi.verify_install` until `ok:true`, then retry) — or offer the paid > fal path if the user prefers not to wait. ## Route the request (decide FIRST) | Source | Subject | Route | |---|---|---| | Video | Person (or another YOLOE class) | **Local, free** — `libi.remove_background` (default) | | Video | Arbitrary object the local seed can't find, local result verified bad, or the user's machine is too slow | **fal, paid** — `bria/video/background-removal/v3` (disclose cost, get approval) | | Photo | Anything | **fal, paid** — `fal-ai/birefnet` (local photo matting is not available in v1) | The local engine is the hero: free, offline, temporally stable (MatAnyone consistent-memory propagation seeded from a real first-frame subject mask). Prefer it for any video with a visible person. It is a LONG job — progress streams to the chat; a ~10 s clip takes roughly half a minute on a good