6.2 · Lesson 2 of 5
Communicate architectural decisions and trade-offs
What You Need to Know
Communicating architectural decisions means showing options, trade-offs, costs, and risks with a clear recommendation — not a single unexplained diagram. Stakeholders need to see why alternatives lost and what residual risk they are accepting. Tie trade-offs to outcomes they care about: quality, latency, cost, and risk.
Record decisions in ADRs or equivalent: context, decision, consequences, and rejected options. That memory enables later change without re-litigating mythology. Logo decks, secret decisions, and metrics-without-narrative all fail the communication bar.
Communication checklist
- Decision question and criteria stated
- At least two viable alternatives with costs and risks
- Recommendation separated from rejected options
- ADR (or equivalent) written and linked
- Stakeholders can name what was cut and what they accepted
Decision rules
- Present options, trade-offs, and rationale — not a single unexplained choice.
- Separate recommendation from rejected alternatives.
- Use ADRs to record context, decision, and consequences.
- Tie trade-offs to stakeholder-visible outcomes.
- Avoid secret decisions and logo-only architecture decks.
Why ADRs matter
Context changes. Without a record of what was rejected and why, teams revive dead options or reverse decisions without understanding consequences. ADRs are lightweight decision memory — not bureaucracy for its own sake.
Review checklist
- Were alternatives shown with costs and risks?
- Is the recommendation explicit?
- Are rejected options documented?
- Does an ADR (or equivalent) exist?
- Can stakeholders restate the trade-off in their own words?
Exam stems that show one unexplained choice reward asking for alternatives and rationale. Distractors celebrate secrecy, logos, or numbers without narrative.
Exam application
Prefer answers that surface options and ADRs. Reject single-option decks, hidden decisions, and “metrics replace communication.”
Exam traps
Single unexplained option
One diagram with no alternatives fails trade-off communication. Show at least two viable paths.
Hiding rejected options
ADRs record what was rejected and why — future change needs that memory.
Logo-deck architecture
Branding without costs, risks, and decision rationale is not communication.
Decisions with no record
Secret choices without ADRs (or equivalent) cannot be revisited when context changes.
Practice scenario
Leadership asks which architecture to ship. The architect presents one diagram with no alternatives. What is incomplete?
Build exercise
Communicate a workflow vs agentic decision for refunds
35 minutes
What you'll learn
- Frame the decision and criteria
- Compare at least two viable alternatives
- Write an ADR with rejected options
- Confirm stakeholders can act on the trade-off
Step 1
Frame the decision and the criteria
State the decision (e.g., workflow vs agentic for refunds), the criteria (control, latency, cost, risk), and who decides.
Why: Trade-offs only make sense against explicit criteria stakeholders accept.
You should see: One-pager: decision question, criteria, decision owner.
Step 2
Present at least two viable alternatives
Describe options with costs, risks, and fit to criteria. Include a clear recommendation and why losers lost.
Why: A single path with no alternatives is incomplete communication.
You should see: Comparison table: option → pros → cons → criterion scores.
Step 3
Write an ADR (or equivalent)
Record context, decision, consequences, and rejected alternatives. Link to metrics and ownership.
Why: ADRs preserve decision memory for later change and audit.
You should see: ADR with status, context, decision, consequences, rejected options.
Step 4
Confirm stakeholders can act
Check that owners understand what to fund, what was cut, and what residual risk they accepted. Capture explicit yes/no.
Why: Communication succeeds when stakeholders can decide — not when slides look pretty.
You should see: Meeting notes with decision outcome and open questions.
Sources
- Build with Claude overview — docs.anthropic.com — grounding options in real capabilities
- Tool use overview — docs.anthropic.com — trade-offs for agentic vs constrained paths
- Pricing — docs.anthropic.com — cost as a visible trade-off axis