---
title: "Architect Agent: AI System Design From Your PRD | ProductOS"
description: "The ProductOS Architect Agent turns your PRD into system architecture: database and API design, deployment and security architecture, ADRs, and cost estimates."
url: https://productos.dev/agents/architect-agent
---

Stage 3 · Define (optional)

# Architect Agent

A system design specialist for the technical half of Define

[All agents](https://productos.dev/agents)

## 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_section`
Writes one of eight architecture sections, the main deliverable
- `record_architecture_decision`
Captures an ADR with context and consequences
- `estimate_infrastructure_cost`
Projects the running cost of the proposed architecture
- `load_constraints`
Reads locked tech-stack facts and project constraints

Reads
- PRD sections
- Structured project constraints
- Locked tech-stack facts

Produces
- Eight architecture sections, from system overview to technical risks
- Architecture decision records
- Infrastructure cost estimates

In the pipeline

[Before: PRD Agent](https://productos.dev/agents/prd-agent) [After: Design Agent](https://productos.dev/agents/design-agent)

## Put the Architect Agent to work.

Every agent works from the same shared context. Describe your idea once and the whole team builds on it.

[Start on Free](https://beta.productos.dev/sign-up?utm%5Fsource=productos.dev/agents/architect-agent) [Meet the whole team](https://productos.dev/agents)