codebase-packager

TLDR Expert

Overview

Achieves high-fidelity codebase comprehension at a fraction of the token cost through semantic layers, structured digests, and advanced context packaging. Combines Repomix for context packing, Gitingest for repository digests, and llm-tldr for graph-based code analysis.

When to use: Reducing prompt overhead for large codebases, onboarding to unfamiliar repositories, mapping cross-file dependencies, creating AI-optimized context bundles.

When NOT to use: Small single-file tasks, final implementation debugging (read the full file), real-time code editing.

Quick Reference

Pattern	Tool / Command	Key Points
Context packing	repomix --include "src/**" --compress	Package subdirectories into AI-optimized bundles
Signatures only	repomix --include "src/**" --compress	Compression extracts signatures via Tree-sitter
Repository digest	gitingest . -o digest.txt	Prompt-friendly summary for quick onboarding
Dependency context	tldr context funcName --project .	LLM-ready context for a function with 95% token saving
Caller tracing	tldr impact functionName .	Reverse call graph to assess change blast radius
Forward call graph	tldr calls .	Build forward call graph across the project
Semantic search	tldr semantic "session expiry" .	Find logic by meaning when naming is inconsistent
Architecture audit	tldr arch .	Detect circular deps, layer violations, dead code
Dead code finder	tldr dead .	Find unreachable functions with zero callers
File extraction	tldr extract src/file.ts	Extract AST (functions, classes, imports) from a file
Secret scanning	Repomix built-in secretlint	Ensure context bundles contain no keys or PII

Common Mistakes

Mistake	Correct Pattern
Reading entire large files without checking structure first	Run tldr extract to get signatures before reading full files
Using grep for dependency tracing across files	Use tldr impact for reverse call graph that understands dynamic imports
Packing node_modules or dist into context bundles	Configure Repomix ignore-list to exclude generated and vendor directories
Assuming semantic search results are exhaustive	Verify top matches against actual source and cross-reference with rg
Running Repomix without compression on large directories	Use --compress flag to stay within context window limits
Including irrelevant context that dilutes signal quality	Follow top-down priority: index, signatures, core logic, then adjacent context

Delegation

• Repository structure discovery: Use Explore agent to map directory layout and identify key modules before building context bundles
• Multi-step context packing workflow: Use Task agent to run Gitingest digest, Repomix compression, and llm-tldr indexing in sequence
• Architecture analysis and planning: Use Plan agent to design context engineering strategy for large monorepos

References

• Context Engineering Patterns -- packing strategies, XML tagging, signal-to-noise optimization, warm-up prompts
• Repomix and Gitingest Mastery -- configuration, compression mode, digest generation, Tree-sitter extraction
• Semantic Graph Analysis -- llm-tldr CLI tools, impact analysis, semantic search, architectural audits