Privacy notice — Oh My Cassette plugin

Last reviewed: 2026-10-21, for 0.5.0. This file is versioned; git log docs/privacy.md is the change history.

This notice covers the Oh My Cassette plugin — the local MCP bridge and the skill in this repository.

Cassette is a separate hosted service that does the editing and rendering. This notice does not speak for it. Anything you send there is governed by your agreement with Cassette.

The short version

The bridge runs on your machine as a stdio child of your agent and opens no port (login briefly binds a loopback callback for the browser sign-in). It contains no telemetry, no analytics, no crash reporting and no update check — nothing reports back to this project. It talks to the Cassette MCP endpoint (https://mcp.trycassette.online/mcp unless you set CASSETTE_MCP_URL), to the sign-in service that endpoint names, and to the upload and download URLs the endpoint hands it (the endpoint’s own origin, or public HTTPS hosts only).

What leaves your machine

What To When
An OAuth access token, as a bearer token the service every call to the service, and to upload or download URLs on the service’s own origin; presigned URLs on other origins get no credential
The refresh token, and the grant to revoke the sign-in service when an expiring access token is renewed, and on logout
oh-my-cassette/<version> as the User-Agent the service every request
Your editing requests and answers, as your agent passes them the service every tool call your agent makes
The workspace: an opaque identifier for its directory and the directory’s name (not its path) the service every tool call
The host’s name and version (e.g. Claude Code 2.x), as the host reports it or CASSETTE_MCP_HOST sets it the service every tool call
For each file a call names: its name, its path relative to the workspace and its absolute path, its size and SHA-256, and its type the service when a tool call names it
The files themselves: prepared for a cloud project, as they are for a project a Mac elsewhere holds the upload URLs the service hands out only when a tool call names them; nothing uploads on startup, in the background or on a schedule

Before upload, video is transcoded on your machine with ffmpeg into the renditions the service declares, which drops the source’s metadata (camera, location, timestamps). Audio and images the service takes as they are upload unchanged, with their embedded metadata — for example a photo’s EXIF GPS position or a song’s ID3 tags; ones it does not take as they are get converted. Files come only from the workspace or CASSETTE_ALLOWED_ROOTS, and only media types unless you set CASSETTE_UPLOAD_ANY_TYPE.

A project made in Cassette for Mac takes its media only into that Mac’s library, so its files are not prepared here. When the bridge runs on that Mac, the app reads each file from its absolute path and nothing uploads. From any other machine each file uploads unchanged, with its embedded metadata, and Cassette deletes the cloud copy once the Mac has it.

Sign-in happens in your browser on Cassette’s own pages (an emailed code and a consent screen); the bridge never sees a password.

What stays on your machine

What Cassette keeps

A project the bridge starts is a cloud project unless you place it on one of your Macs. Cassette deletes it, with its media, after three idle days; every use pushes that back, and each answer says when it is due (retention_expires_at). A project made in Cassette for Mac stays on that Mac and is kept. For anything else Cassette stores, ask Cassette.

Your controls

You want to Do this
Limit what can be read Keep media in the workspace, or grant narrow CASSETTE_ALLOWED_ROOTS — never your whole home directory
Sign this machine out uvx oh-my-cassette==0.6.0 logout — revokes the grant, then deletes the keyring entry
Remove everything local Sign out, delete ~/.config/oh-my-cassette, and uninstall the plugin
Delete a cloud project now Delete it in Cassette, or leave it idle for three days

Reporting

Report a privacy or security problem privately through GitHub private vulnerability reporting, not a public issue. SECURITY.md documents the trust boundaries in more detail.