Compare products on the same criteria, with prices checked

---
name: compare-products
description: Compares products or options side by side on the same criteria, researches each one on the web, checks every price and spec, then recommends one.
spec: skill-graph/1
topology:
  nodes:
    - id: wish
      type: input
      label: WHAT TO COMPARE
    - id: shortlist
      type: orchestrator
      label: SHORTLIST
      model: sonnet
      tools: [WebSearch, WebFetch]
      output_format: json
    - id: research_product
      type: worker
      label: RESEARCH EACH PRODUCT
      model: sonnet
      tools: [WebSearch, WebFetch]
      foreach: shortlist.products
      max_items: 6
    - id: fact_check
      type: verifier
      label: CHECK THE FACTS
      isolated_context: true
      model: opus
      tools: [WebSearch, WebFetch]
      gate: Every price and spec has a source, every product is judged on the same criteria, and nothing is claimed that was not found.
      on_fail: retry
      max_retries: 1
    - id: verdict
      type: synthesizer
      label: VERDICT
      model: sonnet
      tools: [WebFetch]
  edges:
    - from: wish
      to: [shortlist, fact_check, verdict]
    - from: shortlist
      to: research_product
      contract: shortlist_json
    - from: research_product
      to: fact_check
      contract: product_notes
    - from: fact_check
      to: verdict
      contract: checked_notes
contracts:
  shortlist_json:
    format: json
    description: "{ products: the 2 to 5 products to compare, criteria: what to compare them on, budget: the budget or null }"
    required: [products, criteria]
  product_notes:
    format: json
    description: One entry per product, in shortlist order; each has its price and a value for every criterion, each with a source.
  checked_notes:
    format: markdown
    description: The checked facts per product, with sources, and what was corrected or could not be found.
---

# Node Prompts & Edge Contracts

## @node: shortlist
Decide what to compare from this request:

{{wish}}

If the request names products, use those. If not, search the web and pick the 3 that fit it best. Choose 4 to 6 criteria that matter for this choice, such as price, quality, size or support, and note the budget if one is given.

Return JSON: {"products": ["..."], "criteria": ["..."], "budget": "the budget, or null"}.

## @node: research_product
Research this one product:

{{item}}

Criteria to cover: {{shortlist.criteria}}

Find its current price from a shop or the maker, and a value for every criterion from reviews, specs or tests. Note where each fact comes from.

Return a JSON object: {"product": the name, "price": {"value": "...", "source": "link", "date": "..."}, "criteria": {"<criterion>": {"value": "...", "source": "link"}}, "notes": "anything a buyer should know"}.

## @node: fact_check
You are a fact checker. Check this research as if a stranger wrote it.

What the user wants: {{wish}}

The research, one entry per product:
{{research_product}}

Open the sources of the prices and of the specs that decide the choice, and confirm them. Make sure every product is judged on the same criteria. Correct what is wrong, and mark what could not be confirmed.

Return the checked facts per product, each with its source, then a short list of what you corrected or could not confirm.

## @node: verdict
Recommend one option for this request:

{{wish}}

Using only these checked facts:
{{fact_check}}

Return Markdown: a comparison table (one row per product, one column per criterion, plus price), the pick and why in two sentences, the best choice for a different need if there is one, and what to double-check before buying.