Privacy
Where each step runs
“Local” should not be a vague promise. Here is every step Prewatch takes and exactly where it happens.
On your MacClaude API · your keyYour Claude chat
Indexing: all on your Mac
Everything Prewatch needs to index a folder runs on the Mac, with no account and no key.
| Step | Where it runs | What happens |
|---|---|---|
| Decoding video | On your Mac | Hardware decoding with macOS's own AVFoundation and VideoToolbox, inside the app. No video is copied or uploaded. |
| Shots, keyframes and contact sheets | On your Mac | Cuts inside each clip, the sharpest frames of each shot at three sizes, and contact sheets mapped to times. |
| Camera motion and quality flags | On your Mac | Locked off, steady, handheld or shaky per shot; black, frozen, static and flat-log flags. |
| Camera metadata and location | On your Mac | Read from the file itself. Locations are shown as coordinates with no lookup over the network, and recording them can be switched off in Settings. |
| Voice activity and loudness | On your Mac | Finds the stretches with speech so only those are transcribed; loudness and loud moments. |
| Transcription | On your Mac | Whisper (whisper.cpp) on the Mac's GPU. The speech model is downloaded once from huggingface.co; no audio is sent anywhere. |
| Speakers told apart | On your Mac | On-device speaker models shipped inside the app. Labels are anonymous (S1, S2) and no voiceprint is stored. |
| Image tags | On your Mac | Apple's on-device Vision classifier labels the keyframes. |
| Days and scenes | On your Mac | Grouped from the clips' own capture times and locations. |
| Search index and Shotlog files | On your Mac | Written to your disk: next to the footage, or in a library on your Mac. |
Descriptions: the Claude API, with your key, only if you turn it on
Descriptions are opt-in. Nothing is sent until you turn them on in Settings and save your own Claude API key. Before a run, Prewatch shows its estimated cost.
| Step | Where it runs | What happens |
|---|---|---|
| Descriptions and summaries | Claude API · your key | Off until you turn them on and save a key. Sends each clip's keyframes (768 px JPEGs), one overview contact sheet and its facts: file name, duration, camera, shots, flags and the transcript lines with their times. |
| Moments with in-points and shot role | Claude API · your key | Returned by the same request as the description; scored on the Mac for sharpness, steadiness and exposure. |
| Translation into English | Claude API · your key | With descriptions on, transcript text in another language is translated by the same model. Without a key, Whisper translates on the Mac instead (rougher). |
- Never sent: video, audio, locations, and anything about speakers.
- Your key is stored in the macOS Keychain only, used for the request and never written to a file or a log.
- Requests go straight from your Mac to Anthropic. There is no Prewatch server in between.
Chatting: Claude Desktop
When you connect Prewatch to Claude Desktop, Claude reads Prewatch's answers in your conversation. Prewatch keeps them compact, but they are sent to Claude like anything else in the chat.
| Step | Where it runs | What happens |
|---|---|---|
| Prewatch's MCP server | On your Mac | Runs with the app on your Mac and answers Claude Desktop from the Shotlog files. |
| Your conversation | Your Claude chat | What you ask, and what Prewatch answers (clip names, times, transcript lines, descriptions, a scene’s approximate position when your clips carry one, and a frame when Claude checks one), is part of your Claude conversation, under your Claude account and Anthropic's terms. |
| DaVinci Resolve's MCP server | On your Mac | Runs inside DaVinci Resolve Studio on your Mac and makes the changes to your project. |
Privacy policy
The app. Prewatch has no account and collects no data about you or your footage. It contains no analytics or tracking. It connects to the internet only to reach the Claude API with your key when descriptions are on, and to download the speech model from huggingface.co the first time it is needed. Purchases and subscriptions are handled by Apple through the App Store.
This website is hosted on Cloudflare and sets no cookies. It does not run analytics. Cloudflare processes requests to serve the site.
Third parties you choose to use, such as Anthropic for the Claude API and Claude Desktop, and Blackmagic Design for DaVinci Resolve, handle data under their own terms.
Last updated 2026-10-18.