Add Brain Provider

Files (in order)

1. src/engines/<provider>.ts — BrainEngine: name, isAvailable, chat
2. src/engines/index.ts — getEngine() switch
3. src/types/index.ts — BrainType, ApiKeys if BYOK
4. src/lib/brainResolver.ts — isBrainConfigured(), getBrainCostLabel(); fallback copy if BYOK
5. src/lib/brainLabels.ts — getBrainDisplayName()
6. src/components/settings/SettingsPanel.tsx — key + models (free options first)
7. src/components/inspector/NodeInspector.tsx — brain + model dropdown
8. tests/engines/<provider>.test.ts — positive, negative, edge (see test-engineer rule)

BYOK pattern

export function createProviderEngine(apiKey: string): BrainEngine {
  return {
    name: 'Provider',
    isAvailable: () => !!apiKey,
    async chat(messages, options) { /* fetch provider */ },
  }
}

Local engine pattern

• Dynamic import() for heavy deps
• createModelLoadCallback() for download UI
• isAvailable() checks WebGPU / browser support
• Prefer smallest default model

Prometheus

• Register in free-brain selection if usable without key
• Missing key → brainResolver fallback, not crash
• Settings: label cost clearly (Free (local), Free tier, etc.)

Validate

npm run ci

Manual: Demo workflow + agent node on new brain; verify activity log on fallback.

Rules: .cursor/rules/zeroagent-engineer.mdc · .cursor/rules/zeroagent-test-engineer.mdc