The Dual-Layer Contract

This document describes the contract between the Commit Engine and applications.

The Contract

The Commit Engine guarantees structural integrity but NOT semantic integrity.

Layer

Guarantees

Commit

Deterministic merge, DAG consistency, immutability

Application

Semantic validation when consuming state

When concurrent streams converge, mutations are applied using a “best effort” algorithm:

  • Mutations targeting non-existent documents or unresolved paths are silently ignored

  • Business rule violations are NOT detected by the engine

What Commit Provides

Guarantee

Description

DAG Consistency

Commits form a valid directed acyclic graph

Immutability

Once committed, data cannot be modified

Deterministic Merge

Same inputs always produce the same output

Content-Addressable

CommitId = SHA-1(content), tamper-evident

What Commit Does NOT Provide

Not Provided

Description

Intent Preservation

Deterministic arbitration (LWW)

Semantic Validation

No business rule checking

Mutation Notification

No alert when mutations are silently ignored

Conflict Detection

No notion of conflict — just deterministic merge

Summary

“I guarantee structural integrity. You guarantee semantic integrity. Together, we guarantee data integrity. Separately, neither of us can.”

— The Dual-Layer Contract

See Also