find-properties

/tdd-pbt:find-properties — PBT Safety Net: Find Properties

/tdd-pbt:find-properties launches the find-properties agent to analyze an existing TDD implementation and discover properties for property-based safety-net testing.

Step 0 — Detect language

Check whether .tdd-pbt/config.yml exists in the current working directory.

If it exists: read the language field. Use it for all subsequent steps.

If it does not exist: ask the user:

AskUserQuestion:
  question: "Which language and PBT library will you use for this project?"
  header: "Language setup"
  options:
    - label: "Java + jqwik 1.9.3"
      description: "Java project using Maven, JUnit 5, and jqwik 1.9.3"
    - label: "TypeScript + fast-check + Vitest"
      description: "TypeScript project using Vitest and fast-check"

Then write .tdd-pbt/config.yml to the current working directory:

language: java   # or typescript

Confirm: "Language set to . Config written to .tdd-pbt/config.yml."

What you do

1. Collect context from the user's invocation or the current codebase state:

   • Implementation file path (the production code to analyze)
   • Existing TDD test file path (to understand tested behaviors)
   • Target properties file path:
     • Java: src/test/java/<package>/<ClassName>Properties.java
     • TypeScript: src/<ClassName>.properties.test.ts

2. Call the find-properties agent with all collected context as the prompt. Include:

   Language: <java|typescript>
   Implementation file: <path to production code>
   TDD test file: <path to existing test file>
   Properties file: <path for new properties file>
   

3. The agent will:

   • Read the implementation and test file
   • Systematically check all property categories (invariants, roundtrips, idempotence, symmetry, hard-to-verify, test oracle)
   • Java: Create a *Properties.java file with @Disabled("todo") placeholders
   • TypeScript: Create a *.properties.test.ts file with test.todo(...) placeholders
   • Explain each discovered property and why it matters
   • Stop and ask for approval before implementing

4. After the agent completes and reports properties found, wait for the user to confirm before proceeding to /tdd-pbt:implement-properties.

What you must NOT do

• Must not implement property bodies — only signatures with @Disabled("todo") (Java) or test.todo(...) (TypeScript).
• Must not modify the existing implementation or TDD test files.
• Must not write weak properties ("result is not null").
• Must not reimplement the algorithm inside a property assertion.
• Must not proceed to implement-properties without explicit user approval.
• Must not overwrite .tdd-pbt/config.yml if it already exists.