policyengine-model-development

Load when editing a PolicyEngine country model repo (policyengine-us, policyengine-uk, policyengine-canada) — adding or changing variables, parameters, YAML tests, or contributed reforms. This is the engineering layer (how formulas, parameter YAML, and tests are written), distinct from running analysis. Triggers: add a variable, add a parameter, write a formula, defined_for, adds/subtracts, value_type, definition_period, entity, SPMUnit, TaxUnit, vectorize, where/select, period vs period.this_year, monthly_age, YAML test, absolute_error_margin, contrib reform, in_effect, create_x_reform, neutralize_variable, modify_parameters, changelog.d, StateCode, TANF/SNAP encoding, bracket parameter, -.inf, single_amount. NOT for: household calculations, microsimulation, reform scoring, or distributional analysis (use the policyengine skill); calling the REST API (use policyengine-api).