Fix: Context Window Exceeded Error

Error Message:

"Request too large" "Context window exceeded" "Please reduce the length of the input"

The Cause

Claude Cowork has a large context window (200K tokens for standard, up to 1M tokens for Enterprise/Opus 4.6 Beta), but it's not infinite. This error happens when:

1. You uploaded too many large PDFs at once.
2. You asked it to read a massive codebase (thousands of files).
3. The conversation history has become too long.

The Fix

1. Reset the Session

The most common fix. Old conversation history eats up tokens.

• Type /reset or click the New Chat button.
• This clears the history but keeps your files.

2. Use "RAG" Instead of "Read All"

Don't ask: "Read every file in my computer and tell me..." Instead, ask: "Search for files related to 'Quarterly Report' and read only those."

Cowork is smarter when you guide it to the relevant files first.

3. Split the Task

If analyzing a 500-page PDF:

• Step 1: Ask for a summary of Chapters 1-5.
• Step 2: Ask for a summary of Chapters 6-10.
• Step 3: Ask it to combine the summaries.

4. Check for "Junk" Files

Sometimes a folder contains hidden junk files (like node_modules or .git) that are huge but useless.

• Tell Claude: "Ignore any node_modules or .git directories."
• Create a .coworkignore file (similar to .gitignore) in your root directory.