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Local vs cloud AI assistants: what leaves the laptop and what doesn't

Where captured screens, audio, and transcripts live, which models run on your laptop, and what actually leaves the device.

Data boundaryOn-device modelsMCP and exportsSecurity review

Three concrete differences between local and cloud AI assistants

Where raw data lives

With Overshow, OCR text, audio transcripts, and metadata sit in a local SQLCipher-encrypted SQLite database on the laptop. No screen images or video files are persisted. Cloud assistants upload the same content to their provider by default.

Which models do the work

Overshow runs on-device speech-to-text for transcription, on-device speaker labelling, on-device semantic embeddings, and a local language model for chat. All on-device. Cloud assistants call an external API for each of those.

What leaves the device

By default, nothing does. On Pro and Enterprise, you can enable the shipping read-only Memory MCP integration and approve individual AI clients. A query and returned snippets reach a cloud client only when you approve one; an optional source-detail grant can also return a redacted source window. Exports are manual.

What runs on-device in Overshow today

On-device speech-to-text
Transcription

Runs over short rolling windows so words are not cut off at boundaries.

On-device embeddings
Semantic search

Vectors indexed locally alongside full-text search.

Local language model
Chat and questions

Runs on Apple Silicon. No external LLM calls.

Compare it against your current assistant

Install Overshow on one laptop, use it for a week on your real work, and see what you miss from a cloud assistant and what you gain from keeping data local.

The concrete differences that change the security review

Local vs cloud AI assistants

This is a practical comparison, not an ideological one. Both models work. They differ in where captured data sits, which AI runs where, and what you need to explain to your security team.

What runs where in Overshow

Capture, transcription, search, and chat all run on the laptop.

  • Screen capture: hybrid event-driven on macOS. Apple Vision does the OCR.
  • Audio: microphone and system audio, transcribed on-device with on-device speech-to-text over short rolling windows.
  • Speaker labelling: on-device speaker labelling per meeting; profiles are linked locally.
  • Search: full-text search, plus on-device semantic embeddings for semantic search.
  • Chat and Ask: a local language model on Apple Silicon.

Nothing in that list requires a network call to process your captured content.

What leaves the device, and when

The desktop app is local. The account does sit in the cloud, because sign-in, billing, device registration, and aggregate licence-usage counts need to. None of your captured content does. What stays on the machine is the captured content itself.

Optional paths where data does leave:

  • Memory MCP (Pro and Enterprise): the shipping read-only helper stays off until you enable it and approve each client. It returns bounded eligible screen, transcript, or document snippets while the app is running. You choose whether a client may read redacted source detail and can revoke it at any time. A cloud client sends the query and returned content to its provider.
  • Exports: you run them manually when you want to.
  • Cloud assistant integrations (if you add them): require explicit consent and default to local-first.

Where cloud-first is a better fit

Cloud-first assistants are usually the right choice when:

  • You want the most capable frontier models available without buying Apple Silicon.
  • You do not capture screens or audio, only chat transcripts.
  • Your security posture already permits sending work content to the provider.

Where local-first is a better fit

Local-first is usually the right choice when:

  • You record screens or meeting audio and would rather not upload that material to a third party.
  • You work across clients, vendors, or regulated environments and need the boundary to be the laptop.
  • You want semantic search over your own history without an external index service.

Questions to ask before deciding

  • Does the assistant capture your screen or audio? If yes, where is it stored?
  • Can the assistant run transcription and embeddings without a cloud call?
  • What does exporting or deleting everything look like?
  • What does a security reviewer have to approve: an API or a database file?