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ADR-0001: Record Architecture Decisions

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Status

Accepted

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Date

2024-01-15

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Context

As the Skyflow platform grows, we need a way to document significant architectural decisions. Without proper documentation:
  • New team members struggle to understand why certain decisions were made
  • We risk revisiting the same decisions repeatedly
  • Institutional knowledge is lost when team members leave
  • It’s difficult to evaluate past decisions in light of new information
We need a lightweight but consistent approach to documenting these decisions that:
  • Is easy to write and maintain
  • Lives alongside the code
  • Is searchable and versioned
  • Encourages thoughtful decision-making

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Decision

We will use Architecture Decision Records (ADRs) as described by Michael Nygard in his article “Documenting Architecture Decisions.” Each ADR will:
  1. Be stored in the adr/ directory of this repository
  2. Be numbered sequentially (e.g., 0001-decision-title.md)
  3. Follow the template defined in adr/template
  4. Use Markdown format for easy reading and editing
  5. Be immutable once accepted (superseded by new ADRs if changed)
The ADR format includes:
  • Status: The current state of the decision
  • Context: The situation and constraints
  • Decision: What we decided to do
  • Consequences: The results of the decision
  • Alternatives Considered: Other options we evaluated

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Consequences

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Positive

  • Decisions are documented and searchable
  • New team members can understand historical context
  • Forces explicit consideration of alternatives and consequences
  • Creates a decision log that can be reviewed and learned from
  • Lightweight enough to not be burdensome

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Negative

  • Requires discipline to write ADRs for significant decisions
  • May create overhead for smaller decisions
  • Documentation may become stale if not maintained

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Risks

  • ADRs might not be written if the process is seen as too heavyweight
  • The definition of “significant decision” may vary between team members

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Alternatives Considered

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Alternative 1: Wiki-based documentation

We considered using a wiki (Confluence, Notion) for architecture documentation. Rejected because:
  • Wikis are separate from the code
  • Version history is less clear
  • Harder to review as part of PRs
  • May become outdated more easily

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Alternative 2: No formal documentation

We considered relying on code comments and verbal communication. Rejected because:
  • Knowledge is lost when team members leave
  • Difficult to understand historical context
  • Same decisions get revisited repeatedly
  • Onboarding is more difficult

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Alternative 3: Formal architecture documents

We considered creating formal architecture documents with detailed specifications. Rejected because:
  • Too heavyweight for most decisions
  • Discourages documentation due to high effort
  • Becomes outdated quickly
  • Harder to write incrementally

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References