Sub-Phase 1.4: Failure Hardening

Handle all failure scenarios gracefully.

Objective

Must handle:

• Ethos down, Talent up
• Talent unauthorized, Ethos up
• Both unavailable
• Wallet exists in neither

Rules:

• Never fabricate defaults
• Never hide absence
• Never throw on valid input

Analysis Result

The implementation from Sub-Phases 1.1-1.3 ALREADY SATISFIES Phase 1.4 requirements.

No code changes are required. This document formally verifies compliance.

Scenario Verification

Scenario 1: Ethos down, Talent up

Component	Behavior	Status
fetchEthosProfile	HTTP failure → { availability: 'error' }	✅
Promise.allSettled	Does not block Talent call	✅
Output	{ availability: { ethos: 'error', talent: 'available' }, talent: {...} }	✅

Scenario 2: Talent unauthorized (401), Ethos up

Component	Behavior	Status
fetchTalentScore	401 response → { availability: 'error' }	✅
Promise.allSettled	Does not block Ethos call	✅
Output	{ availability: { ethos: 'available', talent: 'error' }, ethos: {...} }	✅

Scenario 3: Both unavailable

Component	Behavior	Status
fetchEthosProfile	Returns { availability: 'error' } independently	✅
fetchTalentScore	Returns { availability: 'error' } independently	✅
Output	{ availability: { ethos: 'error', talent: 'error' } }	✅

Scenario 4: Wallet exists in neither

Component	Behavior	Status
Ethos	Empty array → { availability: 'not_found' }	✅
Talent	Returns points: 0 → { availability: 'available' }	✅
Output	{ availability: { ethos: 'not_found', talent: 'available' }, talent: {...} }	✅

Rule Compliance

Rule	Status	Evidence
Never fabricate defaults	✅	Meta fields use null when unknown
Never hide absence	✅	Availability always explicit
Never throw on valid input	✅	Try/catch in repositories, Promise.allSettled in use case

Output Examples

Ethos Error, Talent Available

{
  "identity": { "address": "0xabc..." },
  "availability": { "ethos": "error", "talent": "available" },
  "talent": {
    "data": { "builderScore": 85 },
    "signals": { "verifiedBuilder": true },
    "meta": { "lastUpdatedAt": "2024-01-15T10:30:00Z" }
  }
}

Both Error

{
  "identity": { "address": "0xabc..." },
  "availability": { "ethos": "error", "talent": "error" }
}

Exit Checklist

Failure Scenarios

• Ethos down, Talent up → handled
• Talent unauthorized (401), Ethos up → handled
• Both unavailable → handled
• Wallet exists in neither → handled

Rule Compliance

• Never fabricate defaults → uses null for unknown values
• Never hide absence → availability always explicit
• Never throw on valid input → try/catch + Promise.allSettled

Architecture

• Repositories return result objects, never throw
• Use case handles all failure states gracefully
• Parallel execution with independent failure handling