Aiwyn Tax MCP Server

Aiwyn Tax is a provider-hosted MCP server (delivered as a Claude Connector) that exposes Aiwyn's tax calculation engine, the same engine underlying the Column Tax platform that has filed over 1 million returns. It provides a complete tax return calculation pipeline: discovering supported tax years and jurisdictions, fetching JSON input schemas for forms and schedules, validating inputs, calculating federal and state returns, and generating downloadable PDF returns asynchronously.

The server supports federal returns plus a single state across 44 state jurisdictions, using a schema-driven input model where every form and schedule is described by a discoverable JSON schema. Workflows typically start with tax_simple_return to bootstrap an example, then fetch namespace schemas, build the input object (with each field wrapped as {"value": <val>}), validate with check_tax, compute with calculate_tax, and generate the 1040 PDF via generate_tax_pdf_tool and get_tax_pdf_tool polling.

The connector is currently in an early pilot phase: it is intended for tax estimation, what-if modeling, and PDF generation rather than production e-filing, and Aiwyn recommends using anonymized or test data until firm-level authentication (Phase 2) is available. Aiwyn states it does not store firm or client data from Claude sessions.

Tools

Aiwyn Tax is delivered as a hosted Claude Connector. There is no package to install and no public GitHub repository to self-host.

Add the connector in Claude

• Open Claude (web, desktop, or mobile) and go to Settings, then Connectors.
• Search for "Aiwyn Tax" or visit the connector page directly: https://claude.com/connectors/aiwyn-tax.
• Click Add / Connect and follow the OAuth prompt.

Use from another MCP client

For clients that accept a remote MCP URL, configure the Aiwyn connector entry exposed through Claude's connector directory. A typical remote MCP entry looks like:

{
  "mcpServers": {
    "aiwyn-tax": {
      "url": "https://claude.com/connectors/aiwyn-tax"
    }
  }
}

Confirm the exact endpoint with Aiwyn before production use, as the connector is currently in a pilot phase.

Prerequisites

• A Claude account with access to Connectors (or an MCP client that supports remote servers).
• During Phase 1 (current pilot), no firm credentials are issued. Aiwyn recommends using anonymized, redacted, or test data per your firm's data governance policy.
• Phase 2 will add firm authentication and governed environments for real client scenarios.

Input format notes

• All field values must be wrapped as {"value": <val>}; do not pass bare values.
• Every item in an array namespace (such as w2 or dependent_detail) must include a uuid field with a valid UUIDv4 string. Use generate_uuid_v5 to link related state and federal entries deterministically.

• Estimate a client's federal 1040 plus state liability from W-2s and other documents and return a downloadable PDF return.
• Run what-if scenarios (filing status changes, additional dependents, IRA contributions) and compare calculated outputs side by side.
• Prototype tax preparation workflows by discovering the JSON schema for a specific form or schedule before building integrations.
• Validate a hand-built tax input object with check_tax to surface schema errors before invoking the full calculation.
• Generate draft 1040 PDFs for firm review during pilot adoption, without replacing existing production tax software.

• "Estimate my 2024 federal and California taxes from this W-2 and give me a 1040 PDF."
• "What tax years and state jurisdictions does Aiwyn currently support?"
• "Show me the input schema for the w2 namespace for tax year 2024."
• "Run a married-filing-jointly scenario with two dependents and $185,000 wages, then compare it to filing separately."
• "Validate this input JSON with check_tax and tell me which fields are missing or malformed."

• Backed by a real production tax engine (Column Tax / Aiwyn) that has filed over 1 million returns.
• Covers federal plus 44 state jurisdictions with full schema discovery, validation, calculation, and PDF generation in one pipeline.
• Hosted by the provider, so there is nothing to deploy or maintain.
• Schema-driven inputs make it well suited for agent workflows that need to introspect forms before building data.

• Currently a pilot connector: no firm-level authentication yet, and Aiwyn advises against using real client data until Phase 2.
• Not a filing system. It computes and produces PDFs but does not e-file returns.
• Supports federal plus a single state per call; multi-state returns are not in scope.
• Strict input conventions (every value wrapped as {"value": ...}, UUIDs on array items) require careful construction.

• Avalara MCP Servers for sales and indirect tax calculations.
• TaxBandits MCP for 1099, W-2, and information-return e-filing workflows.