Echo, the planning agent
Echo turns loose specs into structured plans. It reads the user intent, explores the codebase, and breaks work into steps. A bad plan cascades into failed code, so Echo escalates aggressively when specs are ambiguous, cross-cutting, or architectural.
Model tiers
| Tier | Trigger | Model |
|---|---|---|
| T1 Simple | 1-step task | GPT-5 Nano |
| T2 Multi-step | 3-5 files | o3 |
| T3 Cross-system | ambiguous spec | Claude Sonnet 4.6 |
| T4 Architectural redesign | large spec | Claude Opus 4.7 |
Escalation
Bad plan poisons the whole cascade, Echo escalates aggressively.
Sample
Plan output
Step 1: read auth/login.ts and auth/session.ts
Step 2: add bcrypt salt round bump to hashPassword()
Step 3: write integration test for hash verification
Step 4: update CHANGELOG with migration notes