build-pricing-model

Build Pricing Model

The user wants to create a Swallow pricing engine configuration. Follow this process:

1. Understand the product — Ask clarifying questions if needed: what's being insured, what factors affect the price, what exclusions exist, what the output fields are.

2. Build the input schema — Define all quote input fields. Every input MUST have key, exp, label, sub_label (min 20 chars, broker-facing), type, and def. Without key and exp, the engine ignores quote overrides and always uses def. Input types: string, number, integer, decimal, boolean, date only.

3. Design the step pipeline — Every step MUST have id, step, name, key, and description. Work through the logic in order:

   • Collection steps for rating table lookups (compressed format: [[headers], [row1], ...], must have retain: true)
   • Transform steps to parse/normalise/combine values (must have retain: true; min()/max() NOT supported in exp)
   • Exclusion steps for validity rules
   • Refer steps for manual review triggers
   • Calculation steps for premium, commission, tax (MathJS: use and/or not &&/||)
   • Excess and endorsement steps if needed

   Important: Never use a step type name or its plural as a step key — e.g. never key: "exclusion", "exclusions", "refer", "refers". These collide with Swallow's built-in aggregate variables. Use descriptive prefixed names (e.g. "uw_exclusions", "risk_refers"). Never use key as a data column name in collections. Never use factors, modular, batch, links, label, or code steps.

4. Define the output — Set the result formula, valid expression, and output format. Use {{exclusions.count()}} == 0 in the valid expression. output.format is mandatory — expose per-coverage premiums and key intermediate values. Multiplicative factor defaults must be 1.0 not 0.

5. Add tests — Create at least 3 test cases: happy path, exclusion trigger, and edge case. Every test must include an output object with result (number) and valid (boolean) — never leave output as {}. For excluded cases, set valid: false and result: 0. ALL tests must pass — zero exceptions.

6. Validate — Call validate_swallow_project via MCP to check the schema.

7. Test — Call test_swallow_project via MCP to run the pricing engine and verify results match expectations. If they don't, read result.debug.steps to trace intermediate values and find the FIRST step where values diverge.

8. Iterate — Fix any validation errors or test mismatches and re-run until all tests pass. Never set expected results to match engine output to force a pass — fix the model instead.

Write the final project JSON to a file for the user.