dropbox/pyannotate

Health v2 · maintenance only

Flags: no_releases

Adoption not part of the score

1442 stars · 60 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

PyAnnotate auto-generates PEP-484 type annotations for Python code by collecting argument and return types observed at runtime, then inserting them into source files. It consists of a runtime collection module and a CLI tool that applies the inferred annotations as inline Python 3 annotations or Python 2 style type comments.

Use cases

• add type hints to an untyped Python codebase automatically
• generate PEP-484 annotations from runtime call data
• prepare a legacy project for mypy checking
• collect observed argument and return types during pytest runs
• insert type comments into Python 2 code

When to choose

• you want to bootstrap type annotations for a large untyped Python project
• you already run tests and can observe real call types at runtime
• you plan to adopt mypy and want a starting point for annotations

When to avoid

• you want fully accurate static type inference without running code
• your code paths are not exercised by tests, so few types are observed
• you need annotations maintained continuously rather than generated once

Facets

library · maturity maintenance

type-system developer-tools cli developer-tools programming-languages testing python cli cross-platform type-annotations pep-484 mypy runtime-type-collection code-annotation

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