Lesson Content

How file work happens in Cowork.

Cowork allows you to work with documents directly – uploading files to a Project or session and giving Claude assignments that reference them. Claude can read, analyze, summarize, extract from, compare, and produce output based on the content of those files.

What works well.

• Text-rich documents: reports, proposals, research papers, emails, policies, presentations
• Multiple documents compared or synthesized: "given these three documents…"
• Structured data in tables or spreadsheets: analysis, summarization, pattern identification
• Long documents that would be tedious to manually extract from

Uploading files – in session vs. in Project.

In-session uploads: Files uploaded during a conversation are available for that conversation only. Good for one-off tasks involving a specific document.

Project uploads: Files uploaded to a Project are available across all conversations in that Project. Good for reference materials you will use repeatedly: style guides, client briefs, product documentation, standards documents.

Referencing files in assignments.

When a file is available in the session or Project, tell Claude explicitly which file(s) to use and what to do with them. "Using only the uploaded [document name]…" or "Based on all three uploaded contracts…" are natural references. Ambiguity about which file to use can cause Claude to work from the wrong source or blend sources inappropriately.

Multi-document task patterns.

Common patterns that work well in Cowork:

• Synthesis: "Combine the key points from the three research reports into a single briefing document."
• Comparison: "Compare the approaches described in Document A and Document B on the topic of X."
• Gap analysis: "Given the requirements in Document 1, review Document 2 for any gaps."
• Extraction: "Extract all action items from the meeting notes uploaded here."

For each pattern, specify which documents, what to produce, and in what format.

Reviewing file-based outputs.

When Claude produces output based on documents you uploaded, review it against those documents:

• Did Claude draw from the right sections of the source material?
• Are any key points from the source missing from the output?
• Are any claims in the output not supported by the source documents?

Claude can misread dense or complex documents, summarize at the wrong level of detail, or skip sections it deemed less relevant. Cross-reference significant outputs against source material before use.