AgentTax

What AgentTax MCP server does

The AgentTax MCP server gives AI agents and MCP tool developers access to US tax-compliance operations through the Model Context Protocol. Its main use is recording payments received for paid MCP servers or APIs and obtaining an estimated sales-tax liability based on the buyer’s location, the seller’s configured nexus, and the type of work sold.

The server also covers state economic-nexus thresholds, sales-tax rates, digital-goods taxability, local rates by ZIP code, and state short- and long-term capital-gains rates. Separate trade tools record digital-asset purchases and sales, calculate realized gains using cost basis, and produce a draft Form 1099-DA payload. The draft is not a filed tax return.

This places the AgentTax MCP server in the Finance & Fintech category. It is relevant for developers monetizing agent tools, tracking x402 or other transactions, or maintaining tax records for crypto activity.

How it works

The server runs as an MCP process and sends requests to the AgentTax service. A typical payment flow calls track_payment with an amount, buyer state, optional ZIP code, description, payment identifier, and source. The response includes the tax owed, rate, taxable status, transaction ID, classification, and compliance information. A declared work_type such as compute, content, consulting, or trading can provide a more specific classification; otherwise, the service infers a category from the description.

For larger imports, ingest_transactions accepts up to 100 transactions and avoids duplicate records when the same external transaction ID is reused. Transaction history and running totals are available through list_transactions. Nexus states can be read with get_nexus and updated with configure_nexus, while get_nexus_thresholds reports state thresholds and Department of Revenue sources.

Setup and configuration

Install the package with npx @agenttax/mcp-server and configure it as an MCP server. Claude Code uses claude mcp add; Claude Desktop, Cursor, and Windsurf use their MCP configuration files. Set AGENTTAX_API_KEY for account-backed history and protected operations. Demo mode works without a key and permits 50 calls per day.

An API key can be obtained by submitting an email, password, agent name, and supported agent work type to the AgentTax signup endpoint. The key is shown only once. Account plans include Free, Starter, Growth, and Pro tiers; an x402 option charges per call in USDC on Base.

Tools and capabilities

The AgentTax MCP server exposes tools for:

• Payment tracking, full tax calculations, and bulk transaction ingestion.
• Transaction history, nexus configuration, and nexus-threshold research.
• State and local sales-tax rates, digital-goods taxability, and capital-gains rates.
• Buy and sell logging with realized gain or loss calculations.
• Draft 1099-DA generation, pricing lookup, health checks, and endpoint discovery.

A Stripe webhook can automate payment tracking for selected payment events, including successful payment intents, completed checkout sessions, paid invoices, and successful charges. Stripe must provide a billing address; full address collection should be enabled in Checkout. Product metadata can identify the work type.

Limitations and notes

Tax results depend on accurate transaction details, buyer location, work classification, and nexus settings. Descriptions are classified automatically when work_type is omitted, but inferred classifications do not apply consulting or trading exemptions. The calculate_tax tool treats declared transaction and work types as facts, so callers should not guess them.

Tools requiring an API key include transaction ingestion and history, nexus configuration and retrieval, trade logging and listing, and 1099-DA export. The 1099-DA export additionally requires the Pro tier. Read-only tools carry the MCP readOnlyHint annotation, allowing compatible clients to auto-approve them. AgentTax provides tax calculations and draft data; the supplied material does not describe it as filing returns or replacing professional tax advice.