Large File Handling for Claude Code

Context Limits

Claude Code has these file reading constraints:

25,000 tokens maximum per file read (~100KB of text)
200,000 tokens total context window
Files over 50MB may cause system hangs

Safe Reading Strategies

Use Offset and Limit Parameters

Read specific portions instead of entire files:

Read file with offset=0 limit=500      # First 500 lines
Read file with offset=1000 limit=500   # Lines 1000-1500

Search Before Reading

Find relevant sections first:

grep -n "pattern" large-file.log | head -20

Then read only around matching line numbers.

Blocked File Types

Never attempt to read directly:

Databases: .db, .sqlite, .sqlite3
Archives: .zip, .tar, .gz, .7z
Binaries: .exe, .dll, .so, .bin
Large media: videos, large images

Alternative Approaches by File Type

File Type	Alternative
SQLite DB	`sqlite3 file.db "SELECT * FROM table LIMIT 10"`
Large log	`tail -1000 file.log` or `grep "ERROR" file.log`
JSON (large)	`jq '.specific.path' file.json`
CSV (large)	`head -100 file.csv` or `csvtool`
PDF (large)	`pdftotext file.pdf - \| head -1000`
Minified JS	Usually not needed - read source instead

.claudeignore Best Practices

Add these patterns to prevent accidental reads:

# Binary and database
*.db
*.sqlite
*.exe
*.dll

# Large generated files
*.min.js
*.bundle.js

# Dependencies
node_modules/
vendor/
.venv/

# Build output
dist/
build/
.next/

# Logs
*.log
logs/

Commands Available

/file-check <path> - Check if a file is safe to read
/file-chunk <path> - Get chunking strategy for large file
/scan-large-files [dir] - Find problematic files in directory

When Encountering Large Files

Check size first using /file-check
For text files > 10MB: Use chunking with offset/limit
For logs: Search for relevant patterns first
For databases: Use CLI tools to query
For generated files: Often not needed - read source instead

Large File Handling