xp-practices

The Five XP Values

| Value | Meaning | Practice |

|-------|---------|----------|

| Communication | Everyone knows what everyone does | Daily standups, pairing |

| Simplicity | Simplest thing that works | YAGNI, small design |

| Feedback | Get feedback early and often | TDD, CI, short iterations |

| Courage | Tell truth, adapt | Refactor, admit mistakes |

| Respect | Everyone contributes value | Sustainable pace, pairing |

Core Practices

| Practice | Description | Benefit |

|----------|-------------|---------|

| Pair Programming | Two devs, one workstation | Quality + knowledge sharing |

| TDD | Red-Green-Refactor | Confidence + design |

| CI | Integrate multiple times/day | Fast feedback |

| Collective Ownership | Anyone can change anything | No bottlenecks |

| Sustainable Pace | 40-hour weeks | Long-term productivity |

| Small Releases | Ship frequently | Risk reduction |

---

When to Pair

| Context | Pair? | Why |

|---------|-------|-----|

| Complex/risky code | ✅ Always | Needs multiple perspectives |

| New technology | ✅ Always | Learning accelerator |

| Onboarding | ✅ Always | Knowledge transfer |

| Critical bugs | ✅ Always | Two heads better |

| Simple tasks | ❌ Skip | Not worth overhead |

| Research spikes | ❌ Skip | Pair to discuss findings |

Pairing Dos and Don'ts

Do:

• ✅ Switch roles every 20-30 min
• ✅ Take breaks together
• ✅ Think out loud
• ✅ Ask questions
• ✅ Keep sessions 2-4 hours max

Don't:

• ❌ Grab keyboard without asking
• ❌ Check phone while pairing
• ❌ Dominate conversation
• ❌ Pair all day (exhausting)

---

Setup: 3+ developers, one screen, rotating driver

```

[Screen]

↓

[Driver] ← Directions from navigators

↑

[Navigator 1] [Navigator 2] [Navigator 3]

```

Rotation: Driver switches every 5-10 min

Best for:

• Complex problem solving
• Architectural decisions
• Learning new frameworks
• Resolving blockers

---

CI Workflow:

```

1. Pull latest from main
2. Make small change (<2 hrs work)
3. Run tests locally (all pass)
4. Commit and push
5. CI runs tests automatically
6. If fail → fix immediately

```

Best Practices:

• Commit frequently (small changes)
• Keep build fast (<10 min)
• Fix broken builds immediately
• Never commit to broken build

---

(In priority order)

1. Passes all tests - Works correctly
2. Reveals intention - Clear, expressive code
3. No duplication - DRY principle
4. Fewest elements - No speculative code

---

```typescript

// Agent-human pair testing

const charter = "Test payment edge cases";

const tests = await Task("Generate Tests", { charter }, "qe-test-generator");

const reviewed = await human.review(tests);

await Task("Implement", { tests: reviewed }, "qe-test-generator");

// Continuous integration with agents

await Task("Risk Analysis", { prDiff }, "qe-regression-risk-analyzer");

await Task("Generate Tests", { changes: prDiff }, "qe-test-generator");

await Task("Execute Tests", { scope: 'affected' }, "qe-test-executor");

// Sustainable pace: agents handle grunt work

const agentWork = ['regression', 'data-generation', 'coverage-analysis'];

const humanWork = ['exploratory', 'risk-assessment', 'strategy'];

```

---

Memory Namespace

```

aqe/xp-practices/

├── pairing-sessions/* - Pair/ensemble session logs

├── ci-metrics/* - CI health metrics

├── velocity/* - Team velocity data

└── retrospectives/* - XP retrospective notes

```

Fleet Coordination

```typescript

const xpFleet = await FleetManager.coordinate({

strategy: 'xp-workflow',

agents: [

'qe-test-generator', // TDD support

'qe-test-executor', // CI integration

'qe-code-reviewer' // Collective ownership

],

topology: 'parallel'

});

```

---

| Objection | Response |

|-----------|----------|

| "Pairing is 2x slower" | 15% slower writing, 15% fewer bugs, net positive |

| "No time for TDD" | Debugging takes longer than testing |

| "CI is hard to setup" | Start simple: one action, one test |

| "Collective ownership = chaos" | Only without tests + CI |

---

• [tdd-london-chicago](../tdd-london-chicago/) - TDD deep dive
• [refactoring-patterns](../refactoring-patterns/) - Safe refactoring
• [pair-programming](../pair-programming/) - AI-assisted pairing

---

XP practices work as a system. Don't cherry-pick randomly:

• TDD enables collective ownership
• CI enables small releases
• Pairing enables collective ownership
• Sustainable pace enables everything

With Agents: Agents amplify XP. Pair humans with agents. Agents handle repetitive work, humans provide judgment and creativity.