Why does this matter?
There is no single "Claude". You have the regular chat on claude.ai, the agentic Cowork mode, and Claude Code for actually building, and the last two each exist in a web and a local variant. People lump them together and then wonder why one can "reach their files" and the other can't. Keep the forms apart and you pick the right one faster, and you know exactly what happens with your files and data.
These forms evolve fast and some are still young. The underlying logic is stable, though, and that is what we put front and centre here.
The two questions that decide everything
- Where does it run? On your device (local) or in the vendor's cloud (Anthropic). This decides whether it can reach your real, local files.
- What is it for? For knowledge work and no-code (chatting, writing, research) or for real projects: your own files, systems and automation, up to software.
With those two questions, every form falls into place.
The forms at a glance
- claude.ai Chat / Project: the regular chat. Runs in the cloud and only knows what you type or upload (with a Project: fixed instructions and uploaded context). No access to your local drive.
- Cowork (web/mobile): Claude's agentic mode. The session runs on Anthropic's servers, keeps going in the background and syncs across your devices. Great for agentic knowledge work, but without direct access to your local files.
- Cowork (desktop app): the same Cowork, but the app on your computer acts as the bridge to your device. That lets Cowork reach local files, but scoped: only the folders you connect, and only while the app is open. Local connectors and MCP also work through the desktop app only (and through Claude Code).
- Claude Code, local (CLI, VS Code extension or a local session in the app): the engineering agent that works natively on your machine. Full access to the folder or repo you open, plus commands, git, tools and MCP. This is the heavy variant for real projects.
- Claude Code, web/cloud: the same agent, but in a cloud sandbox with a cloned GitHub repo, not your local drive. Handy when you're away from your own machine. Such cloud sessions can later be resumed locally in VS Code.
Everything side by side
| Mode | Where it runs | Access to your local files | What for |
|---|---|---|---|
| claude.ai Chat / Project | Vendor's cloud | No, only what you type or upload (instructions + context) | Quick conversation, writing, no-code |
| Cowork, web/mobile | Cloud session (keeps running in the background) | No, only indirectly via the desktop app as a bridge | Agentic knowledge work, building something without code |
| Cowork, desktop app | Session in the cloud, the app is the bridge to your device | Limited: only connected folders, and only while the app is open. Plus local connectors/MCP | Same as Cowork web, with access to local files and tools |
| Claude Code, local (CLI / VS Code / desktop extension) | Your machine (local) | Yes, full & native (the folder/repo you open) + commands, git, tools, MCP | Real projects: files, systems, automation (incl. software) |
| Claude Code, web/cloud | Cloud sandbox | No, works on a cloned GitHub repo in the cloud | Same as local, but without your own machine |
Web or local: where's the real difference?
"Web versus local" means something different for Cowork than for Claude Code.
- With Cowork, the session always runs in the cloud. Only the desktop app can reach your local files, and even then only the folders you explicitly connect and while the app is open. So web versus app really comes down to: can it reach my device or not?
- With Claude Code, the difference is more fundamental. Local means it works natively on your real files (the folder you open), without a connector. Web/cloud means a cloned repo in a sandbox, so not your local drive.
In short: with Cowork, web-versus-app is about whether there's a bridge to your device; with Claude Code, it's the real difference between your files and a copy in the cloud.
When do you choose what?
- Just asking or writing something → Chat or a Project.
- Agentic knowledge work, no code → Cowork. Use the desktop app if you need to reach local files or tools.
- Real files or systems on your machine → Claude Code local (CLI or VS Code).
- Claude Code, but you're away from your own machine → Claude Code web/cloud on a repo.
Two questions settle it: where does it run (your machine or the cloud) and what is it for (knowledge work or real projects). Everything else follows from that.
Related terms
- Claude subscription or API key?: how you access the model and where the application around it runs, regardless of which form you use.
- What is MCP?: the standard Claude uses to reach your tools and data through connectors.
- What is a CLI?: the command line, the environment where Claude Code runs locally.
