Module 04

Evidence and Proof

Learn how Ota captures and interprets execution evidence: receipts, archives, runtime and lifecycle proof, negative controls, freshness, replay, promotion, and semantic identity.

Module curriculum

Lessons in Evidence and Proof

Follow the sequence to build the model, then use the exercises to test the boundary.

Lesson 019 min read

Receipts and archives

Receipts are typed, producer-bounded evidence; archives preserve identity-bound history without expanding what the evidence proves.

Describe the structure of a receipt
Explain what makes a receipt tamper-evident

Lesson 028 min read

Runtime and lifecycle proof

Runtime proof evaluates selected runtime obligations; lifecycle proof additionally binds phase transitions, teardown authority, and exact cleanup.

Distinguish runtime proof from task exit-code proof
Run ota proof runtime and read the result

Lesson 037 min read

Negative controls

Runtime negative controls challenge a proof obligation; refusal canaries separately verify agent admission remains closed.

Explain why negative controls are essential for agent safety
Write a negative control for a protected path

Lesson 048 min read

Freshness, replay, promotion, and identity

How Ota tracks whether a receipt is still valid (freshness), whether an execution can be replayed, and how semantic identity ties inputs to outputs.

Explain what makes a receipt stale
Describe semantic identity hashing