Single Source of Truth¶

Give each authoritative fact or policy one canonical owner.

Canonical interpretation¶

Derived views may be duplicated, but authority and synchronization rules must be explicit.

Purpose¶

Give each authoritative fact or policy one canonical owner.

Apply when¶

Knowledge or policy is duplicated in ways that can diverge.
A stable variation axis or public extension boundary has been demonstrated.

This does not mean¶

Do not require all data to live in one physical database.
Do not confuse caching or denormalization with multiple authorities when reconciliation is defined.

Trade-offs¶

An abstraction introduces coupling between its consumers.
Premature reuse can make independently changing concepts harder to modify.

Conflicts with canonical entries¶

eventual-consistency

Broader policy tensions¶

availability

Reinforces canonical entries¶

dry
information-hiding

Supports broader concerns¶

None recorded.

Core Skill ownership¶

Primary owner: abstraction-and-reuse

Positive example¶

Store the canonical status once and derive presentation labels.

Counterexample¶

Allow two services to independently decide the same business status without reconciliation.

Guidance for AI models¶

Apply this guidance only after considering the active project profile, constraints, and architecture authority.
State the concrete design consequence instead of citing the principle name as sufficient justification.

Editorial note¶

This page is generated from the canonical YAML entry. Edit principles/entries/single-source-of-truth.yaml and regenerate the compendium instead of editing this file directly.