Does this skill require Dafny to be installed?

Yes, the skill utilizes the local dafny_compile tool, so you must have the Dafny environment installed and configured on your system.

What testing frameworks does it support for property-based testing?

It currently generates test suggestions for Python using the Hypothesis library and for Go using the Rapid library.

Can I track if future changes break my verified logic?

Yes, the skill can register your verified functions in a spec registry, allowing you to run regression checks that verify if the logic still holds after code edits.

How does it handle complex Dafny types like BigRational?

The skill identifies Dafny-specific types in the output and provides a mapping guide to replace them with native equivalents, such as Python's fractions.Fraction or Go's big.Rat.

Dafny Code Extractor

Name: Dafny Code Extractor
Author: nicholls-inc

bynicholls-inc

•

Security & Testing

Compiles verified Dafny programs into clean, production-ready Python or Go code with automated property-based test generation.

The extract-code skill bridges the gap between formal verification and production implementation by automating the conversion of verified Dafny logic into idiomatic Python or Go. It eliminates runtime boilerplate, provides native type mapping suggestions, and identifies potential semantic divergences. Crucially, it translates formal postconditions into executable property-based tests using frameworks like Hypothesis or Rapid, ensuring that the extracted code maintains its mathematical guarantees within the target environment's constraints.

Key Features

01Registers verified specs for automated regression tracking in your project

02Flags abstraction gaps and potential semantic divergences (e.g., float precision)

03Compiles verified Dafny to clean, boilerplate-free Python or Go

04Generates property-based test suites derived from formal postconditions

05Provides native type mappings for Dafny-specific types like BigRational and Seq

063 GitHub stars

Use Cases

01Maintaining a registry of verified properties to prevent regressions during refactoring

02Integrating formally verified algorithms into production Go backends

03Converting verified logic into Python modules with Hypothesis test coverage

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add nicholls-inc/claude-code-marketplace extract-code

For use in Claude.ai and ChatGPT

Key Features

01Registers verified specs for automated regression tracking in your project

02Flags abstraction gaps and potential semantic divergences (e.g., float precision)

03Compiles verified Dafny to clean, boilerplate-free Python or Go

04Generates property-based test suites derived from formal postconditions

05Provides native type mappings for Dafny-specific types like BigRational and Seq

063 GitHub stars

Use Cases

01Maintaining a registry of verified properties to prevent regressions during refactoring

02Integrating formally verified algorithms into production Go backends

03Converting verified logic into Python modules with Hypothesis test coverage

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add nicholls-inc/claude-code-marketplace extract-code

For use in Claude.ai and ChatGPT