Behavior Characterization

Detect what the system does today without judging whether it is ideal.

Observable signals

• Return values.
• Exceptions and error codes.
• Side effects and state changes.
• Persistence writes/reads.
• Published events.
• Relevant logs.
• External calls.
• Edge conditions and branch behavior.
• Implicit business rules.

Every behavior claim needs code evidence or must be marked as a hypothesis.

Characterization method