Tracking Docstring Drift by Hashing Public Symbols and Flagging Signature-Only Changes

A small internal Python library suffered from documentation that fell out of step with its code, such as a docstring still listing a parameter name that had been renamed. The author built a deterministic ledger that hashes each module-level symbol's signature and docstring and compares them against a committed snapshot. A symbol is flagged only when its signature changed while its docstring stayed the same, since an edited docstring means someone has already reviewed it. Because the diffing is deterministic, a language model is needed only as an optional annotation on symbols already flagged, and the test suite can run offline against a fake client. The tool is scoped to Python signature and docstring drift and does not attempt to certify that documentation is correct.