DSPy Nomenclator

DSPy Nomenclator is a Python library for explainable Harmonized System (HS) code classification built on DSPy.

It combines deterministic retrieval over the official HS nomenclature with structured LLM reasoning to produce accurate, transparent, and legally grounded classifications.

The library uses a multi-stage retrieval and reasoning pipeline to progressively narrow the search space—from product analysis, through chapter and heading retrieval, to final HS code classification with supporting rationale.

Features

• 🌳 Parses the official HS 2022 nomenclature into a structured tree
• 🔎 Two-stage hybrid retrieval over chapters and headings (semantic + BM25)
• 🤖 Multi-stage DSPy pipeline for product analysis, research, and classification
• ⚖️ Applies chapter notes and the General Rules for Interpretation (GIR) during classification
• 📊 Built-in benchmarking framework for evaluating classification quality
• 🧩 Modular architecture with typed intermediate models and independently testable components

Installation

pip install dspy-nomenclator

Configure an OpenAI-compatible API key before running DSPy.

For example:

export OPENAI_API_KEY=...

Quick Start

Install the package and classify a product directly from the command line:

nomenclator "Men's cotton knitted shirts"

Example output:

╭────────────────────────────────────────────────────────────────────────╮
│ Nomenclator (openai/gpt-4.1-mini)                                      │
╰────────────────────────────────────────────────────────────────────────╯

Product
  Men's cotton knitted shirts

╭───────────── Best Classification───────────────────────────────────────╮
│ HS Code       6105.10                                                  │
│ Confidence    1.00                                                     │
│ Description   Men's or boys' shirts, knitted or crocheted — Of cotton  │
│ Chapter       6101-2022E                                               │
╰────────────────────────────────────────────────────────────────────────╯

Reasoning
├── Product is a knitted cotton shirt for men, matching heading 61.05 and subheading 6105.10 criteria.
├── Chapter 61 notes specify applicability to knitted or crocheted garments, confirming the correct chapter.
├── Heading 61.05 is the most specific heading for men's knitted shirts, consistent with GIR 3(a).
├── Other headings, including those for woven shirts or women's garments, do not apply.
└── No competing heading provides a more specific classification.

╭─────────────────────── Performance ────────────────────────╮
│ Prompt tokens          18,053                              │
│ Completion tokens      648                                 │
│ Total tokens           18,701                              │
│ Estimated cost        $0.00826                             │
╰────────────────────────────────────────────────────────────╯

The CLI also accepts input from standard input:

echo "Fresh bananas" | nomenclator

Run nomenclator --help to see all available options.

How it works

Q: "Men's cotton knitted shirts"
        │
        ▼
┌─ Product Analyst ──────────────────────────────────────────────┐
│  normalized: men's cotton knitted shirts                       │
│  category:   textile apparel                                   │
│  attrs:      type=shirt · material=cotton · knit               │
│  keywords:                                                     │
│    • cotton shirt                                              │
│    • knitted shirt                                             │
│    • knitted apparel                                           │
│    • textile apparel                                           │
│    • garments                                                  │
└────────────────────────────┬───────────────────────────────────┘
                             │
                             ▼
┌─ Chapter Retriever (1st retrieval) ────────────────────────────┐
│  hybrid search over HS chapters                                │
│                                                                │
│    Ch.61  Articles of apparel, knitted or crocheted            │
│    Ch.62  Articles of apparel, not knitted or crocheted        │
│    …                                                           │
└────────────────────────────┬───────────────────────────────────┘
                             │
                             ▼
┌─ Research Analyst ─────────────────────────────────────────────┐
│  analyze candidate chapters                                    │
│                                                                │
│    1. Ch.61  Primary pathway                                   │
│    2. Ch.62  Alternative pathway                               │
└────────────────────────────┬───────────────────────────────────┘
                             │
                             ▼
┌─ Heading Retriever (2nd retrieval) ────────────────────────────┐
│  hybrid search over heading chunks                             │
│                                                                │
│    Ch.61  61.05 → 6105.10                                      │
│    Ch.62  62.05 → 6205.20                                      │
│    chapter notes + heading context                             │
└────────────────────────────┬───────────────────────────────────┘
                             │
                 ┌───────────┴───────────┐
                 │  GIR Rules (fixed)    │
                 └───────────┬───────────┘
                             ▼
┌─ Classification Analyst ───────────────────────────────────────┐
│  rank HS classification candidates                             │
│                                                                │
│  1. 6105.10  Men's or boys' shirts, knitted, of cotton         │
│     score 1.00                                                 │
│                                                                │
│  2. 6205.20  Men's or boys' shirts, of cotton                  │
│     score 0.30                                                 │
└────────────────────────────┬───────────────────────────────────┘
                             │
                             ▼
┌─ Classification Result ────────────────────────────────────────┐
│  ✓ Selected: 6105.10                                           │
│                                                                │
│  Confidence: High                                              │
│  Alternatives: 6205.20                                         │
│  Reasoning:                                                    │
│    • Product is a knitted cotton shirt.                        │
│    • Chapter 61 is more specific than Chapter 62.              │
│    • GIR 3(a) favors the most specific heading.                │
└────────────────────────────────────────────────────────────────┘

Development

Install the project dependencies:

poetry install

Optionally, install Poe the Poet globally for shorter commands:

pipx install poethepoet

Common development tasks:

poe format       # Format and auto-fix the source code
poe lint         # Run static analysis
poe typecheck    # Run type checking
poe test         # Execute the unit test suite
poe integration  # Execute the integration test suite
poe check        # Run linting, type checking, and unit tests

Coding agents working in this repository follow the rules described in AGENTS.md

Architecture

For a detailed overview of the system design, pipeline flow, retrieval strategy, and agent responsibilities, see:

• 👉 Architecture

Roadmap

Completed:

• ✅ Two-stage hybrid retrieval (chapter and heading levels)
• ✅ Multiple embedding backends (Sentence Transformers and FastEmbed)
• ✅ Classification benchmarking and evaluation framework

Planned improvements:

• DSPy optimization using evaluation datasets
• Interactive terminal UI (TUI) for product classification and result exploration
• Optional audit stage for reviewing classification results
• Support for additional customs nomenclatures (e.g. TARIC, HTSUS)

License

MIT License.