Block Tax IntelligenceSource-grounded tax research, built for the frontier.
The research engine behind Block Tax. Ask cross-border tax questions, model scenarios, and inspect every answer against the structured corpus and its source trail — never against a model's memory.
A research workflow, not a chatbot.
Every query passes through a five-layer verification chain. Answers are anchored to Block Tax's structured corpus first; LLMs sit inside the workflow, never at the front of it.
- 01
Question parsing
Jurisdictions, taxes, entity types, transaction patterns and time periods are extracted into a structured query — not a free-text prompt.
- 02
Corpus retrieval
Relevant provisions are pulled from the Block Tax structured corpus: domestic legislation, treaty articles, EU directives, OECD commentary, and extracted source notes.
- 03
Reasoning & synthesis
State-of-the-art LLMs reason over the retrieved set inside a controlled workflow — model orchestration, not model improvisation.
- 04
Primary-source check
Each substantive claim is matched back to citable source text. Claims that can't be matched are flagged for human review rather than rounded out.
- 05
Citation & trace
Answers carry numbered citations down to the article and paragraph. Click through to read the source text in place — no black-box answers.
What the engine is reading.
Five source layers. Each indexed, cross-linked to the others, and refreshed daily — so an answer about a German WHT rate cites the same primary text a German tax adviser would open.
Domestic legislation
Tax codes, regulations and administrative guidance from 76 jurisdictions — corporate tax, withholding, VAT, capital gains, transfer pricing.
Tax treaties
44k+ treaty provisions indexed at article level. DTAs, protocols, MLI modifications, and the resulting effective treaty network.
Supranational instruments
EU directives and regulations — ATAD, IRD, PSD, DAC series including DAC8, VAT directive — plus the OECD framework: MTC, BEPS, Pillar Two, CARF.
Commentary & case law
OECD Commentary on the Model Convention, ECJ rulings on direct tax matters, and curated landmark decisions from key jurisdictions.
Block Tax research notes
First-party practitioner notes from the Block Tax research desk. Working interpretation where primary sources are silent, ambiguous or in motion — clearly marked as commentary, never as authority.
The kinds of questions it's built for.
The public site stays open.
The engine stays gated.
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