Architecture Decision Pack

What the Organization asks for before its AI team starts work.

The company

Thistle Commerce. Platform team of six.

The decision

How Orders and Inventory should communicate after the service split

Why now

Five weeks of argument and three written proposals. No convergence.

Current state

Two services, deployed separately, still sharing one database

Hard constraint

Inventory has a 99.5 percent availability target in a customer contract

Unknown at intake

How stale stock counts are allowed to be. Nobody had asked.

Infrastructure

No message broker in production today

Deadline

Decision by 10 October, build in Q4

Attached by the buyer.

• Three written proposals, A B and C (MD)
• Current service and database schemas (SQL)
• Incident records, 12 months (CSV)
• Throughput metrics including Black Friday 2025 (CSV)

1. Client provides product requirements, current stack, constraints and existing architecture notes.
2. Requirements agent separates product behavior from implementation assumptions.
3. Architecture agent proposes options and trade-offs without pretending to inspect systems it cannot access.
4. Interface agent structures data ownership, contracts, failures and dependencies.
5. Final technical decisions remain with the engineering team.

• Problem statement
• Constraints
• Architecture options
• Trade-offs
• Recommended decision criteria
• Interfaces/data ownership
• Failure modes
• Open engineering questions