Documenting Principles
Architecture principles guide consistent decision-making across teams. Learn how to capture, communicate, and maintain principles that shape your technical direction.
Principles establish the rules your architecture follows. They encode hard-won lessons, organisational values, and technical standards into reusable guidance. Without documented principles, teams make inconsistent choices and repeat the same debates.
The Principle Block
A dedicated block type for principles includes fields that capture not just the rule, but the reasoning behind it.
This example uses the NeoArc Principle content block.
Principle Scope
Principles apply at different levels. The scope field clarifies where a principle is relevant:
This example uses the NeoArc Principle content block.
Rationale and Implications
The most important parts of a principle are often the rationale and implications, not the statement itself.
Handling Exceptions
Most principles have exceptions. A principle that allows no flexibility is either too narrow to be useful or will be routinely violated.
This example uses the NeoArc Principle content block.
Principle Lifecycle
Principles evolve as organisations learn and technology changes. The status field tracks where each principle stands:
The reviewDate field schedules periodic reviews. Technology principles from five years ago may no longer reflect current best practice.
Principles vs Constraints
Principles and constraints both guide architecture decisions, but they differ in important ways:
| Type | Definition | Flexibility |
|---|---|---|
| Principles | Chosen guidelines you adopt because they lead to better outcomes | Can be revisited when circumstances change |
| Constraints | Imposed limitations from outside your control | Require escalation to whoever imposed them |
"We use TypeScript for all frontend code" is a principle if your team chose it for maintainability. It becomes a constraint if mandated by enterprise standards you cannot change.
Writing Good Principles
Effective principles share common characteristics:
| Quality | Description |
|---|---|
| Actionable | Clear enough to guide decisions. "Design good APIs" is too vague. "APIs must be versioned using URL path segments" is actionable. |
| Testable | You can verify whether code follows the principle. Include examples of compliance and violation. |
| Justified | The rationale is documented and convincing. Principles without rationale feel arbitrary. |
| Scoped | Clear about where they apply. Organisation-wide principles need broader buy-in than team conventions. |
Adding a Principle Block
The principle blocks you see throughout this documentation site were created using this same workflow.
Common Principle Categories
Architecture teams typically document principles in these areas: