Learn

Practical articles for developers who have to read, draw or document code they did not write.

Reading code

• How to understand a new codebase: a step-by-step method, from the README and the run command to tracing one request and checking what an AI tells you against the code.
• How to understand an agentic AI codebase quickly: where to look for the agent loop, tools, memory, prompts and guardrails.

Documenting code

• Draw an architecture diagram from your code: why hand-drawn diagrams drift, and what a diagram derived from code can and cannot show.
• How to document a LangGraph project: find the graph, the state, the nodes and edges, the interrupts and the checkpoints, and verify each claim in the code.

See it applied

How RepoLantern turns a repository into a guide and how every guide is checked. The full documentation covers each feature step by step.

Who uses it, and for what

• Joining a team or taking over legacy code. Ask "how do I understand this codebase?" and get a quick start, the main modules, how data flows and a glossary, with every claim linked to the lines it rests on. A method you can follow by hand
• Tech leads and architects. Review a system from architecture diagrams drawn from the code's real imports, and read the deep dive for design decisions and readiness checks. Diagrams from code
• Consultants and reviewers. Get a first read of a client's repository, with the names it could not verify listed rather than hidden. Private repositories work with a read-only token that is used once.
• Open-source newcomers and students. Learn from a real project with the beginner's guide, then ask questions beside it.
• Engineering managers. Hand new hires a guide to the code and a glossary instead of a stale wiki page.
• People building AI agents. Read an open-source agent or LangGraph project quickly. Agentic AI codebases · LangGraph projects