---
type: DecisionTool
title: "W-8 Series Structural Validator"
description: "Validates W-8 series form structural consistency for withholding tax compliance. Checks: form-type/Chapter 3 status compatibility (FORM_CH3_MISMATCH for W-8BEN-E + Individual mismatch etc.), Chapter 3/Chapter 4 FATCA cross-check (CH3_CH4_INCONSISTENT), 3-year validity window expiring Dec 31 of third year per Treas. Reg. 1.1441-1(e)(4)(ii) (FORM_EXPIRED), and treaty dividend rate against IRS Pub 901 table (TREATY_RATE_MISMATCH). Returns is_structurally_valid, violations[], validity_expiry_date, and days_until_expiry. Structural form codes only. No TIN. Zero PII by construction."
resource: https://ainumbers.co/chaingraph/art-269-validate-w8-series-structural.html
tags: ["compliance_mandate", "wave-45", "mcp:validate_w8_series_structural"]
timestamp: 2026-07-14
generated: { by: "ainumbers/generate-okf", at: "2026-07-14" }
status: stable
sources:
  - resource: https://ainumbers.co/chaingraph/graph/nodes/art-269-validate-w8-series-structural.json
    title: "chaingraph.json shard entry"
  - resource: https://ainumbers.co/chaingraph/art-269-validate-w8-series-structural.html
    title: "public tool page"
---

# W-8 Series Structural Validator

> Exports a decision via MCP `validate_w8_series_structural` — mandate type `compliance_mandate`.

## Inputs

Typed `inputSchema` — see [tool page](https://ainumbers.co/chaingraph/art-269-validate-w8-series-structural.html).

## Outputs

A hash-anchored OpenChainGraph artifact (decision, not context).

## Chains

**Consumes:** [FinCEN CDD 25% Beneficial Ownership Attribution](./art-268-compute-cdd-ownership-25pct.md)

**Feeds:** _terminal node_

## Attested computation

[executor + attester binding](../computations/art-269-validate-w8-series-structural.md) — §10.2.