Large File Handling

Documents

This skill should be used when the user asks about "reading large files", "file too big", "context limit", "chunking files", "offset and limit", "file causing crash", or when encountering files over 10MB. Provides strategies for safely reading large files without exhausting context.

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How to use this skill

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I want to install this Agent Skill for this project in Codex.

Source SKILL.md: https://github.com/majiayu000/claude-skill-registry/blob/HEAD/skills/development/large-file-handling/SKILL.md

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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