6.5Decision Logs

Decision logs record why certain choices were made. They are invaluable when a new team member asks "why do we do it this way?" or when the team revisits a decision months later.

Decision Log Format

# Decision: [Title]

**Date:** [YYYY-MM-DD]
**Decision-makers:** [Names]
**Status:** Accepted / Superseded by [link]

## Context
What situation prompted this decision?

## Options Considered

### Option A: [Name]
- Pros: ...
- Cons: ...

### Option B: [Name]
- Pros: ...
- Cons: ...

## Decision
Which option was chosen and why.

## Consequences
What trade-offs were accepted. What follow-up actions are needed.

Example Decision Log

# Decision: Choosing Playwright over Cypress for E2E Testing

**Date:** 2025-09-15
**Decision-makers:** QA Lead, Engineering Manager, Senior SDET
**Status:** Accepted

## Context
Our Cypress test suite has grown to 350 tests and is experiencing
significant pain points: single-browser limitation (we need Safari),
no native multi-tab support, and slow execution (45 min for full suite).

## Options Considered

### Option A: Stay with Cypress
- Pros: No migration cost, team is familiar, large community
- Cons: No Safari support, single-tab only, performance ceiling

### Option B: Migrate to Playwright
- Pros: Multi-browser (including Safari), multi-tab, faster execution,
  better debugging tools, auto-wait reduces flakiness
- Cons: Migration cost (~3 weeks), team retraining needed

### Option C: Use both (Cypress for existing, Playwright for new)
- Pros: No migration risk, gradual transition
- Cons: Two frameworks to maintain, double the learning curve

## Decision
Migrate fully to Playwright (Option B). The migration cost is
justified by the long-term benefits of multi-browser support
and performance improvements.

## Consequences
- 3-week migration sprint dedicated to converting tests
- Team training sessions scheduled for weeks 1-2
- Cypress will be fully removed after migration is verified
- Expected 40% reduction in suite execution time