Languages

What is supported today

Language	Provider	Extensions
Python	python.py	.py, .pyi
TypeScript / JavaScript	typescript.py	.ts, .tsx, .js, .jsx, .mjs
Go	go.py	.go
Java	java.py	.java

Anything else is still read: a file no provider claims is chunked on line windows and embedded, so it is searchable and readable in the source viewer. What it does not get is symbols, imports, calls, or framework-aware facts.

What a provider does

A LanguageProvider is the only place in the codebase that knows anything language- specific. It answers:

• Which files are mine, by extension.
• What is declared here — every symbol with its kind, its qualified name, and its line span. This is what makes a chunk a whole function instead of an arbitrary window, and what fills graph_symbols.
• What does this file import, resolved to repository paths where it can be.
• What calls what, where the callee is unambiguous.
• What framework facts are visible — a FastAPI decorator is a route, a Gin handler is a route, an os.environ read is an env var.
• What to skip — node_modules, __pycache__, vendor, and the rest.

Python's provider is the most complete, because it was first and because the product was built in it. Go and Java extract symbols, imports and routes; TypeScript adds the studio's own idioms.

The rule

No language-specific code outside codelith/languages/

Python's ast, file extensions, framework idioms — all of it lives behind LanguageProvider. Agents and the knowledge base speak the neutral vocabulary in codelith/languages/taxonomy.py and codelith/knowledge/constants.py.

Adding a language means adding one provider. Not touching agents, not touching the schema, not touching the apps.

This is not a style preference. It is what keeps a thirteen-kind entity vocabulary meaningful across four languages, and what makes the fifth cheap.

Adding one

1. Write a provider in codelith/languages/providers/, implementing the interface.
2. Register it.
3. Run the conformance suite. tests/unit/languages/conformance.py is shared across providers: it asks every one of them the same questions and checks the shape of the answers, so a new provider is held to what the existing ones already do.

There is no step four. If you find yourself editing an agent, the agent is asking for something the provider should be answering.

Path handling

Paths inside the knowledge base are POSIX-style and repo-relative, always.

Backslashes are normalised to forward slashes wherever a path is compared, on every platform — not because Windows needs it, but because being wrong there is silent: one native path slipping past a filter means a whole vendored tree gets analysed, embedded, and paid for, with nothing to show that the filter did not fire.