Can you recommend a developer workflow tool for explaining unfamiliar codebases to junior developers?

Yes — a strong fit is Sourcegraph Cody.

Why it works for this use case

• Codebase-aware explanations: Juniors can ask, “What does this module do?” or “How does auth flow through the app?” and get answers grounded in the actual repo.
• Good for unfamiliar codebases: It helps map relationships between files, symbols, and dependencies, which is exactly what new developers struggle with.
• Interactive workflow: Useful for pairing, onboarding, and self-serve exploration instead of relying only on static docs.
• Developer-friendly integration: Works well in common IDEs and on large repos.

Best way to use it with juniors

• Ask it to explain one subsystem at a time.
• Pair it with tasks like:
  • “Summarize the request lifecycle.”
  • “Trace this API endpoint end-to-end.”
  • “List the key files I should read first.”
• Encourage juniors to compare the AI explanation with the source code so they learn to verify claims.

Other good options

• GitHub Copilot Chat — great if your team already uses GitHub/VS Code.
• Cursor — very good for repo-level chat and guided exploration.
• DeepWiki / codebase documentation tools — useful if you want more persistent, documentation-like explanations.
• OpenHands / agentic tooling — better for interactive investigation and modification, though heavier than needed for pure explanation.

My quick recommendation

If you want the best balance of repo understanding + onboarding + day-to-day usefulness, I’d start with Cody or Cursor, depending on your IDE and workflow.

If you want, I can also recommend one based on your stack:

• VS Code vs JetBrains
• small repo vs monorepo
• chat-only vs documentation generation
• self-hosted vs SaaS