Architecture

For readers who want to know why DD is built this way, or who want to change it.

• Behavioural contract: what the code guarantees today. Where it and src/ disagree, the code wins and the document is fixed.
• Plugin constraints: seven limits a plugin for coding-agent harnesses lives inside. A proposal that fails one is rejected on that basis alone.
• Invariants: properties that must never break, and what enforces each.
• Where DD came from: what v1 was, what measurement showed, and the mistakes v2 must not repeat.