## TL;DR
Parse the .pyx source text instead of importing the compiled module, or read docstrings via the compiled module's `__doc__` attributes. Cython's compiled output hides source structure from AST parsers.

## Error
```text
(docstring extractor returned empty for cython module; no exception, just missing docs)
```

## Steps
1. Confirm the module is Cython: look for .pyx sources or a compiled extension. Expected: the Cython nature confirmed.
2. Point the parser at the .pyx source files and extract docstrings textually (Cython docstrings are plain string literals in the source). Expected: docstrings recovered from source.
3. Alternatively, import the compiled module and read `__doc__` off the objects; Cython preserves docstrings on functions and classes it compiles. Expected: docstrings available at runtime.
4. Wire the chosen source into the agent's extraction step and regenerate. Expected: Cython symbols documented.

## When to use
- Doc extraction yields nothing for Cython modules
- The agent uses Python AST parsing, which cannot see compiled code
- Mixed Python/Cython codebases with doc gaps

## When not to use
- The module is pure Python (a different parser bug)
- Docstrings are missing from the .pyx source too (an authoring gap)
- The compiled module lacks `__doc__` (check the Cython build settings)

## Tool compatibility
Cython 0.29 and 3.x; docstring behavior is the same. Any AST-based extractor hits this.

### Variant phrasings
### parser works on .py but not .pyx in the same run
Branch the extraction: AST for Python, source-text or runtime for Cython.

### cdef class docstrings missing
Cython exposes docstrings on extension types; read them at runtime if source parsing misses them.

## Why it happens
AST parsers expect Python syntax trees, but Cython modules ship as compiled binaries or .pyx files with Cython-specific syntax. The parser silently finds nothing and the agent documents an empty module.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_2n_0qiRdU4pbHZ-YkLjYzw