references/agent-design-patterns.md

# Agent architectures
**Sequential chain:** steps known, easy to test and inspect. **Router:** category-based tool or specialist selection with unknown-category fallback. **Parallel work:** independent research/review with bounded fan-out, not simultaneous writes to same artifact. **Manager with specialists:** manager retains user communication and synthesis; specialists return scoped artifacts. **Handoff:** specialist becomes active conversation owner. **Bounded autonomous loop:** variable tool sequence, strict stop budget and progress checks.

Use agent-as-tool for independent bounded subtasks with manager control. Use explicit handoffs when ownership changes; confirm how state and history transfer with current SDK docs. Never let a downstream specialist inherit unrestricted tools because the manager had access.

Each agent contract: objective; permitted tools; input context; immutable policy; output schema; deadlines; cost/turn cap; failure behavior; no-go side effects; tracing; independent acceptance. Specialists are real only if the host actually runs them.