plat-multifamily-underwriting

Deterministic multifamily underwriting engine: rent roll / T12 ingestion, a schema-validated canonical deal format, monthly cashflow + waterfall math, and a statute-cited property-tax regime module. Numbers come from the engine, not from a model. The same inputs always produce the same outputs.

python3 -m venv .venv && source .venv/bin/activate
pip install -e ".[dev]"
pytest

What this is

Quick start — run the intake CLI on the synthetic fixtures:

python runs/ingest_deal.py --rent-roll tests/fixtures/sample_rent_roll.csv \
  --t12 tests/fixtures/sample_t12.csv --start 2026-05 --end 2031-04 \
  --property-id "Sample Deal" --output output/sample.json --validate

Honest limitations

• Synthetic-only validation. Every fixture in this repository is synthetic. No live offering memorandum, rent roll, or T12 is shipped, and parser coverage is not claimed beyond the synthetic fixtures and formats in tests/.
• Property tax regimes require human review. engine/tax_regimes.py and docs/TAX_REGIME_SCHEDULES.md cite statutes, but rates, assessment ratios, and revaluation cadences must be reviewed by a qualified professional per jurisdiction before production use.
• No invented numbers. Missing millage, missing rent, unknown unit status -> blockers and None, never silent zeros.
• LLM OM extraction is opt-in. The default install parses nothing with a hosted model. The om-llm extra enables the Anthropic-based OM extractor; the core engine never imports it.

Layout

engine/          deterministic underwriting modules + canonical schema
engine/schemas/  deal_schema_v0_1.json (canonical deal format)
engine/ingest/   rent roll / T12 / OM parsers
tests/           synthetic fixtures only
runs/            ingest_deal.py intake CLI
docs/            specs, module docs, tax regime schedules

Contributing

Synthetic fixtures only — never commit real deal documents, property names, tenant IDs, or credentials. See CONTRIBUTING.md and SECURITY.md. DCO sign-off required.

License

Apache-2.0. See LICENSE.