invariants

Scope: Architectural invariants.
Audience: Contributors.
Guarantees: Invariants map to tests.
Non-Goals: Rationale narrative.
Why: This doc exists to record its single responsibility for review.

Overview

This doc defines one responsibility.
Architecture components are defined in Architecture.
Read Docs Style before edits.
Read Triage for context.

Contracts

Each statement is a contract.
Contracts align with tests/regression/test_architecture_invariants.py.
Contracts link to Docs Style and Triage.

Invariants

Invariants describe stable behavior.
Checks align with tests/regression/test_architecture_invariants.py.
Invariants align with Docs Style.

Failure Modes

Failures are explicit and tested.
Failure coverage aligns with tests/regression/test_architecture_invariants.py.
Failures align with Triage.

Extension Points

Extensions require tests and docs.
Extensions are tracked in Docs Style.
Extensions align with tests/regression/test_architecture_invariants.py.

Exit Criteria

This doc becomes obsolete when the surface ends.
The replacement is linked in Triage.
Obsolete docs are removed.

Code refs: tests/regression/test_architecture_invariants.py.