This directory contains Architectural Decision Records (ADRs) for the Keystone Core project.

What is an ADR?

An Architectural Decision Record (ADR) is a document that captures an important architectural decision made along with its context and consequences.

ADRs help us:

• Document the reasoning behind significant decisions
• Communicate decisions to the team and stakeholders
• Provide historical context for future developers
• Track the evolution of the architecture over time

When to Write an ADR

Write an ADR when making decisions that:

• Affect the overall system architecture
• Are difficult to reverse or have long-lasting impact
• Involve trade-offs between competing concerns
• Affect security, performance, or scalability
• Change fundamental assumptions or patterns
• Introduce new dependencies or remove existing ones
• Affect the public API or user experience significantly

Examples:

• Choosing a database technology
• Adopting a new messaging pattern
• Changing authentication mechanisms
• Selecting a framework or major library
• Defining API versioning strategy

ADR Status

ADR Index

Creating a New ADR

1. Copy the template:

   cp docs/adr/0000-adr-template.md docs/adr/NNNN-short-title.md

2. Use the next sequential number (NNNN)

3. Fill in all sections of the template

4. Submit as a pull request for review

5. Update this index after the ADR is accepted

ADR Lifecycle

┌──────────┐     Review      ┌──────────┐
│ Proposed │ ─────────────→  │ Accepted │
└──────────┘                 └──────────┘
     │                            │
     │ Reject                     │ Supersede
     ▼                            ▼
┌──────────┐                 ┌────────────┐
│ Rejected │                 │ Superseded │
└──────────┘                 └────────────┘
                                  │
                                  │ or Deprecate
                                  ▼
                             ┌────────────┐
                             │ Deprecated │
                             └────────────┘

Best Practices

1. Be concise but complete: Include enough context for future readers
2. Focus on the “why”: Explain the reasoning, not just the decision
3. Document alternatives: Show what was considered and why it was rejected
4. Keep it current: Update status when decisions change
5. Link to related ADRs: Reference related decisions
6. Include examples: Show how the decision applies in practice

References

• ADR GitHub Organization
• Documenting Architecture Decisions - Michael Nygard
• ADR Tools