Foundations · Lesson 02 of 04
Contract, execution, admission, and evidence
The four pillars of Ota: a declared contract, deterministic execution, admission gates, and receipts that prove what actually ran.
Learning objectives
- Name the four pillars and state what each covers
- Explain why evidence must be separate from execution
- Describe what an admission gate prevents
Prerequisites
Ota separates declaration, admission, execution, and evidence because each answers a different question. Collapsing them creates false confidence: valid YAML is not readiness, an admitted plan is not completed execution, and a receipt is not automatically an acceptance decision.
Four distinct layers
The contract declares supported intent. Admission resolves one invocation against that contract and applicable policy before side effects. Execution performs the selected work. Evidence records the bounded observations and outcomes produced by that operation.
- Declaration answers: what should this repository require?
- Admission answers: may this exact invocation begin?
- Execution answers: what work ran and with which resolved selection?
- Evidence answers: what can another consumer inspect afterward?
ota run --dry-run --json testAcceptance belongs at an adopted gate
Ota produces contract, admission, execution, and evidence truth. A team decides which Ota verdicts and proof identities are mandatory for merge or release through branch protection, CI policy, or another adopted chokepoint. A receipt is evidence consumed by that gate; it does not appoint itself as organizational approval.
Canonical terminology
Evidence boundary for this lesson
Establishes
- The four pillars are understood conceptually
Does not establish
- Any specific contract is valid or well-formed
Knowledge check
Why can a valid receipt not appoint itself as a merge approval?
A receipt is bounded evidence. An adopted branch-protection, CI, or organizational policy decides which evidence is mandatory for acceptance.