Design

1. Read $MIGRATION_DIR/.phase-status.json. If missing, invalid, or phases.clarify is not exactly "completed": STOP. Output: “Phase 2 (Clarify) not completed or phase state is missing/invalid. Run references/phases/clarify/clarify.md until Clarify finishes and .phase-status.json shows phases.clarify: completed.”
2. Read $MIGRATION_DIR/preferences.json. If missing: STOP. Output: “Phase 2 (Clarify) not completed. Run Phase 2 first.”

Check which discovery artifacts exist in $MIGRATION_DIR/:

• gcp-resource-inventory.json (IaC discovery ran)
• gcp-resource-clusters.json (IaC discovery ran)
• billing-profile.json (billing discovery ran)
• ai-workload-profile.json (AI workloads detected)

If none of these artifacts exist: STOP. Output: “No discovery artifacts found. Run Phase 1 (Discover) first.”

Routing Rules

Infrastructure Design (IaC-based)

IF gcp-resource-inventory.json AND gcp-resource-clusters.json both exist:

→ Load design-infra.md

Produces: aws-design.json

Billing-Only Design (fallback)

IF billing-profile.json exists AND gcp-resource-inventory.json does NOT exist:

→ Load design-billing.md

Produces: aws-design-billing.json

AI Workload Design

IF ai-workload-profile.json exists:

→ Load design-ai.md

Produces: aws-design-ai.json

Mutual Exclusion

• design-infra and design-billing never both run (billing-only is the fallback when no IaC exists).
• design-ai runs independently of either design-infra or design-billing (no shared state). Run it after the infra/billing design completes.

Phase Completion

Before marking Design complete, enforce route output gates (fail closed):

1. Determine which design routes ran:
   • IaC route: gcp-resource-inventory.json AND gcp-resource-clusters.json exist
   • Billing-only route: billing-profile.json exists AND gcp-resource-inventory.json does NOT exist
   • AI route: ai-workload-profile.json exists
2. Require at least one route to be active. If none active: STOP.
3. For each active route, require its expected artifact:
   • IaC route -> aws-design.json
   • Billing-only route -> aws-design-billing.json
   • AI route -> aws-design-ai.json
4. If any active route is missing its expected output: STOP and output: “Design route [name] did not produce required artifact(s). Re-run the failed sub-design before completing Phase 3.”

Completion Handoff Gate (Fail Closed)

Load shared/handoff-gates.md. Re-read from disk each active route artifact before checking.

Re-entry guard: If estimation-infra.json (or sibling estimate artifacts) exists and phases.estimate is "completed": STOP unless the user explicitly confirms re-running Design. Emit GATE_FAIL | phase=design | field=estimation-infra.json | reason=stale_downstream.

On any route gate FAIL: Emit GATE_FAIL | phase=design | field=<artifact> | reason=missing. Do NOT modify artifacts to pass the gate. Do NOT update .phase-status.json.

On PASS: Emit HANDOFF_OK | phase=design | artifacts=<comma-separated active design files>.

Inner workshop reprice — skip state transition

When Design is invoked from workshop-refresh.md (inner reprice): rewrite the active design artifact(s) (aws-design.json and siblings as applicable), then return to the workshop loop. Do not emit HANDOFF_OK, do not set phases.design to "in_progress" or re-stamp "completed", do not change current_phase, and do not treat Estimate as stale for a Generate reset unless the user is already past Generate (see workshop-refresh stale-Generate guard). Leave phases.design and phases.estimate as "completed" and current_phase at "estimate" while phases.workshop is "in_progress".

Design summary card (outer runs only — before the phase-status update)

After outer-run HANDOFF_OK, present a compact card built from the design artifact(s) so the user sees what Design decided before costs arrive. Chat only — not a file:

Use the user-facing vocabulary from design-refs/fast-path.md for “How we chose this” (Standard pairing / Tailored to your setup / Estimated from billing only) — never raw deterministic/inferred enum values. Cap the table at 5 rows (“+ N more in the design artifact”). Skip this card entirely on inner workshop reprices.

After the card, use the Phase Status Update Protocol (read-merge-write) to update .phase-status.json — in the same turn as the output message below:

• Set phases.design to "completed"
• Set current_phase to "estimate"

Output to user: “Phase 3 of 6 complete (Design). AWS architecture designed. Remaining: Estimate → Generate (+ optional Feedback). Next artifact: estimation-infra.json (and estimation-ai.json for AI workloads). Proceeding to Phase 4: Estimate Costs.”

Breadcrumbs are emitted only after outer-run HANDOFF_OK — never on GATE_FAIL, never from inner workshop reprices.

Reference Files

Sub-design files may reference rubrics in design-refs/:

• design-refs/index.md — GCP type → rubric file lookup
• design-refs/fast-path.md — Direct (table) mappings vs rubric path; User-facing vocabulary for presenting confidence to users (Standard pairing / Tailored to your setup / Estimated from billing only)
• design-refs/compute.md — Compute service rubric
• design-refs/elastic-beanstalk.md — Elastic Beanstalk reference (App Engine, managed platform)
• design-refs/database.md — Database service rubric
• design-refs/storage.md — Storage service rubric
• design-refs/networking.md — Networking service rubric
• design-refs/messaging.md — Messaging service rubric
• design-refs/ai.md — AI/ML service rubric

Scope Boundary

This phase covers architecture mapping ONLY.

FORBIDDEN — Do NOT include ANY of:

• Cost calculations or pricing estimates
• Execution timelines or migration schedules
• Terraform or IaC code generation
• Risk assessments or rollback procedures
• Team staffing or resource allocation

Your ONLY job: Map GCP resources to AWS services. Nothing else.