Skip to content

CBSA Steel Derivative Goods Surtax

💡 TL;DR - A new business system, derived straight from a government regulation

Created by: 💬 create project demo_customs_surtax from samples/prompts/customs_cbsa.prompt.md

  • The prompt reads actual CBSA steel-surtax regulations off the web
  • AI distills that regulatory text directly into declarative rules
  • The ad-libs report lists every low-confidence decision, so you know exactly where it guessed

Browse the code: demo_customs_surtax on GitHub

Status: Reference implementation

CBSA Steel Derivative Goods Surtax

Audience: Technical GenAI-Logic evaluators

Project: CBSA Steel Derivative Goods Surtax Order calculator (PC Number 2025-0917, program code 25267A)

 

Executable Requirements - Governance By Architecture, At Scale


This demo creates an entire subsystem — database, API, business logic, and Admin App — from a single natural language prompt, using Method 4 (System Creation Services).

Unlike the Customs CLVS demo (which starts from an existing database and adds relationship/logic fixes), this project is generated fresh, end-to-end, from the prompt alone. The prompt is the requirement; Context Engineering ensures the result is enterprise-class — governed, auditable, and correct — not just a working demo.

 

Claude Code CLI Instructions


Execute these steps from the Manager, using the Claude Code terminal.

A. Activate Claude Code

Open the Claude Code terminal in the Manager.

B. Activate the venv

🤖 Paste into the terminal
! source ../venv/bin/activate

C. Implement the project from the prompt

🤖 Paste this into the Claude Code chat (Agent mode, Claude Sonnet 4.6 recommended)
implement project demo_customs_surtax from samples/prompts/customs_cbsa.prompt.md

This single instruction drives Method 4 (System Creation Services) end-to-end:

  1. Loads Context Engineering (.github/.copilot-instructions.md)
  2. Creates the project (genai-logic create --project_name=demo_customs_surtax ...), generating the database, models, API, and Admin App from the prompt
  3. Translates the prompt's business rules into declarative logic/logic_discovery rules (not procedural FrankenCode)
  4. Generates seed test data and runs the test suite
  5. Writes docs/requirements/readme.md (provenance) and docs/requirements/ad-libs.md (every assumption made beyond the prompt spec)

 

The Prompt

Prompt: samples/prompts/customs_cbsa.prompt.md
Create a fully functional application and database
 for CBSA Steel Derivative Goods Surtax Order PC Number: 2025-0917 
 on 2025-12-11 and annexed Steel Derivative Goods Surtax Order 
 under subsection 53(2) and paragraph 79(a) of the 
 Customs Tariff program code 25267A to calculate duties and taxes 
 including provincial sales tax or HST where applicable when 
 hs codes, country of origin, customs value, and province code and ship date >= '2025-12-26' 
 and create runnable ui with examples from Germany (CETA — exempt), US (CUSMA — exempt), Japan (CPTPP — exempt), and China (subject, 25%)
  Transactions are received as a CustomsEntry with multiple 
SurtaxLineItems, one per imported product HS code.

 

Domain Summary

Transactions are CustomsEntry records with one or more SurtaxLineItem rows (one per HS code).

Tax calculation chain

Step Rule Table
1 Copy effective_date, program_code, pc_number from SysConfig CustomsEntry
2 Copy country_surtax_rate from CountryOrigin CustomsEntry
3 Copy province_tax_rate from Province CustomsEntry
4 surtax_applicable = 1 when ship_date >= effective_date AND country_surtax_rate > 0 CustomsEntry
5 Copy base_duty_rate, is_steel_derivative from HsCodeRate SurtaxLineItem
6 surtax_applicable = 1 when entry surtax_applicable == 1 AND is_steel_derivative == 1 SurtaxLineItem
7 base_duty_amount = customs_value * base_duty_rate SurtaxLineItem
8 surtax_amount = customs_value * country_surtax_rate (if line surtax_applicable) SurtaxLineItem
9 Sum total_customs_value, total_duty_amount, total_surtax_amount CustomsEntry
10 duty_paid_value = total_customs_value + total_duty_amount + total_surtax_amount CustomsEntry
11 sales_tax_amount = duty_paid_value * province_tax_rate CustomsEntry
12 total_tax_due = total_duty_amount + total_surtax_amount + sales_tax_amount CustomsEntry

Example countries in seed data

Country Agreement Surtax rate
Germany (DE) CETA 0%
United States (US) CUSMA 0%
Japan (JP) CPTPP 0%
China (CN) — 25%

Provinces in seed data

Province Tax rate (pre-combined GST/PST/HST)
Ontario (ON) 13%
Alberta (AB) 5%
British Columbia (BC) 12%
Nova Scotia (NS) 15%
Manitoba (MB) 12%

 

Results: System, Test Suite and Report

System: API, Database, Logic, Admin App

The GenAI-Logic create command builds a complete, runnable project: the JSON:API server (with Swagger), a full CRUD Admin App, and 18 declarative rules in logic/logic_discovery/cbsa_steel_surtax.py implementing the tax calculation chain above.

Test Suite and Report

The GenAI-Logic create command also builds test services and Context Engineering. These enable the LLM to generate tests that prove the code works, and to produce readable test reports that elucidate the logic.

 

How it Works

Authoring

  1. Copilot loads Context Engineering (.github/.copilot-instructions.md, docs/training)
  2. Invokes genai-logic create --project_name=demo_customs_surtax ... to scaffold the project — database, models, API, Admin App — all runnable, but no logic yet
  3. Copilot then, under the guidance of Context Engineering:
    • Translates the prompt's business rules into declarative rules (logic/logic_discovery, not FrankenCode)
    • Generates seed test data (with values initialized per rules)
    • Runs the test suite

Execution

Execution uses deterministic runtime engines (ORM, API, Logic) — no probabilistic AI calls at runtime. The result is correct by architecture, auditable to regulators, and maintainable by a single developer.