What runs locally, what goes to the cloud, and how to use Cowork mode safely with sensitive business data.
Claude Cowork mode runs locally on your computer — meaning the task execution, file creation, and processing happen on your machine, not on a remote server. However, the AI itself (Claude) is cloud-based: your prompts and context are sent to Anthropic’s servers to generate responses. This is a key distinction that matters for how you handle sensitive information.
When you use Claude Cowork mode, there are two separate data flows happening:
1. The AI conversation (sent to Anthropic): When you type a prompt and Claude generates a response, the content of your conversation — including your prompt and any context Claude needs — is transmitted to Anthropic’s servers. This is how all Claude products work: the AI model runs in the cloud. Anthropic processes this data to generate your response.
2. File operations (local only): When Cowork mode reads a file from your computer, creates a new document, or moves files in your folder, these operations happen locally on your machine. The file contents are not uploaded to a server — they are read and processed locally, and the output is written locally.
The practical implication: the content of a document you ask Claude to read may be sent to Anthropic as part of the conversation context (so Claude can understand and respond to it). The file itself stays on your computer and is not separately stored on Anthropic’s servers.
Anthropic’s privacy policy (available at anthropic.com/privacy) covers how your conversation data is used. Key points for Cowork mode users:
For the most current and accurate information, always check Anthropic’s official privacy policy directly, as terms can change.
For most standard business tasks — writing reports, creating presentations, drafting emails, doing market research — Claude Cowork mode is safe to use in the same way you would use any cloud productivity tool like Google Docs or Microsoft 365. Your data is transmitted to generate responses but is not sold or publicly disclosed.
However, there are categories of information where you should exercise extra caution:
When you connect apps via MCP connectors — Slack, Gmail, Google Drive — you authorise Claude to access those apps on your behalf. Here is how the security works:
OAuth authorisation: You never give Claude your passwords. The connection uses OAuth, the industry-standard authorisation protocol. You grant specific, scoped permissions — for example, read-only access to specific Slack channels, not your entire account.
Revocable at any time: You can disconnect a connector through Claude’s settings at any time. You can also revoke access directly through the connected app’s security settings (e.g. Google Account → Security → Third-party apps).
Minimal permissions principle: Well-implemented MCP connectors request only the permissions they need. Check what permissions you are granting before authorising any connector.
Anonymise where possible. If you need Claude’s help with something involving real people’s data, anonymise names and identifiers before pasting into your prompt. This significantly reduces privacy risk without limiting Claude’s ability to help.
Check your training data settings. In Claude’s settings, you can opt out of having your conversations used for model training. If you regularly use Cowork mode for business work, enabling this setting is worth doing.
Use Team or Enterprise plans for sensitive work. If you are using Cowork mode for work that involves sensitive business data at scale, a Claude Team or Enterprise plan comes with stronger privacy protections and a data processing agreement — important for GDPR compliance in the UK and EU.
Be aware of what you paste. The most common privacy mistake is not the tool itself but users pasting more sensitive information than they need to. Use the minimum data necessary to achieve the task.
Claude Cowork mode has a comparable privacy model to other major AI productivity tools — Microsoft Copilot, Google Gemini, and ChatGPT all involve sending conversation context to cloud servers for AI processing. Anthropic’s privacy practices are well-documented and the company has a strong stated commitment to AI safety and responsible data handling.
For everyday business and personal productivity use, Claude Cowork mode is a safe and legitimate tool. The key is to understand how the data flow works and make informed decisions about what you include in your prompts.
For the most accurate and up-to-date privacy information, review Anthropic’s Privacy Policy and the Claude usage policies at anthropic.com. If you have specific compliance requirements (GDPR, HIPAA, etc.), contact Anthropic directly to discuss Enterprise options.
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