What is PDD?

Puzzle Driven Development breaks features into small, working increments. Each increment leaves @todo puzzle comments marking deferred work. This lets multiple agents (AI or human) work in parallel and progress without being blocked by incomplete pieces.

A good increment:

• Passes tests — never leave failing tests as technical debt
• Has working stubs — throws an error indicating that the stub is still unimplemented; never silently swallow unimplemented behaviour
• Documents context — the @todo comment should give the next agent enough to start without reading all the history

@todo Comment Format

// @todo #1234 Short description of what to implement:
//  - Bullet point of expected behaviour
//  - Reference to related patterns (e.g., "See <file> for ...")
//  - Dependency notes (e.g., "Needs <something> from #1235")
//  - Acceptance criteria
doSomething() {
  throw new Error("doSomething not yet implemented")
}

Key rules:

• @todo followed by the ticket you are working on. For example, if you are working on issue #1234 say @todo #1234. The ticket reference will depend on the issue tracking system used, e.g. #1234 for GitHub, or ABC-1234 for Jira/Linear, or CLAUDE-1 for Claude Code's built-in task list. If it is unclear which ticket is being worked on, ask the operator for this information before continuing.
• No iteration or phase numbers — don't write @todo Add create action in phase 2; implementation order can change
• For subsequent lines after the // @todo, indent by one space, i.e. add 2 spaces after the line comment, e.g. // -.
• Always pair the comment with a stub so callers fail loudly

When to Wrap Up With a Stub

If you think you're spending too long on a task:

1. Get tests to pass with a minimal implementation
2. Write a @todo comment that explains:
   • The context on what you are working on
   • What you tried and why it didn't work so far
   • What the next agent needs to know to continue the work without repeating your failed attempts
3. Create a task in your task list referring to the todo comment you created.

Picking Up an Existing Puzzle

When you find a @todo to implement:

1. Read the comment fully — it should have context, bullets, and file references
2. Check the ticket numbers in issue tracker for acceptance criteria
3. Study the referenced files/patterns before writing code
4. Remove the @todo comment when the implementation is complete
5. Run the relevant tests to confirm nothing breaks