A system design specialist for the technical half of Define
What does the Architect Agent do?
“A system design and technical architecture specialist.”From the agent's actual system prompt
The Architect Agent is the optional technical deep-dive inside the Define stage. From the PRD and your locked constraints it produces real architecture documents: system overview, container architecture, database and API design, deployment and security architecture, design patterns, and technical risks.
It records architecture decisions as ADRs and can estimate infrastructure cost, so the build that follows starts from decisions, not defaults. It designs the system; it does not write the app code.
What tools does the Architect Agent use?
write_architecture_sectionWrites one of eight architecture sections, the main deliverable
record_architecture_decisionCaptures an ADR with context and consequences
estimate_infrastructure_costProjects the running cost of the proposed architecture
load_constraintsReads locked tech-stack facts and project constraints
Put the Architect Agent
Every agent works from the same shared context. Describe your idea once and the whole team builds on it.