Estimate

Calculate projected monthly AWS costs for the designed Heroku-to-AWS architecture, producing estimation-infra.json (conforming to references/vendored/estimate/estimation-infra.schema.json) and classifying migration complexity using the tier thresholds in references/vendored/estimate/complexity-tiers.json.

Composed of a cost-engine fragment + one assembler (declared in the frontmatter _fragments/_assemble); the interpreter runs the fragment, then the assembler, and evaluates the _knowledge guards to load the pricing/defaults/tier data. The fragment selects the pricing mode and computes the financial picture; the assembler writes the final artifact, runs the completion gate, presents the summary, and offers the optional what-if workshop sidebar (references/phases/workshop/workshop.md, _kind: sidebar), then the post-Estimate Decision gate — read each unit file for its own contract. Outer Estimate defers current_phase → generate until both the workshop AND the Decision gate are resolved (see estimate-assemble.md).

Decision gate deviation from _advances_to (documented exception): this phase’s frontmatter declares _advances_to: generate, which the interpreter loop treats as the default next current_phase on HANDOFF_OK. The Decision gate’s choice A (“Done for now”) deliberately overrides that default and sets current_phase: "complete" instead, leaving phases.generate at "pending" (the decide-complete state) — see estimate-assemble.md § “Post-Estimate: Decision Gate”. This is a documented exception to “advance to _advances_to“, in the same spirit as the inner-workshop-reprice path documented below skipping HANDOFF_OK entirely: both exist because the phase orchestrates a user choice the frontmatter’s static routing cannot express. Choice C (“Generate Terraform and migration scripts”) follows _advances_to normally.

Scope Boundary

This phase covers financial analysis ONLY.

FORBIDDEN — Do NOT include ANY of:

• Changes to architecture mappings from Phase 3 (Design)
• Execution timelines or migration schedules (beyond tier classification)
• Terraform or IaC code generation
• Detailed migration procedures or runbooks
• Team staffing, human labor costs, or professional services fees
• AI workload estimation (not applicable to Heroku migrations)

Your ONLY job: Show the financial picture of moving from Heroku to AWS. Nothing else.