AgentTax

Tax compliance tools for AI agent transactions — calculate US sales tax across 51 jurisdictions, track capital gains (FIFO/LIFO), monitor economic nexus, and generate 1099 reports. Built for autonomous AI-to-AI commerce.

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AgentTax MCP Server

Tax compliance for MCP tool developers and AI agents, powered by AgentTax.

For MCP tool developers

If you build MCP tools that charge for usage, you have sales tax obligations in states where your buyers are located. Most payment processors don't handle this correctly for digital services.

Add AgentTax to your MCP setup and call track_payment after every payment. That's it.

{
  "mcpServers": {
    "agenttax": {
      "command": "npx",
      "args": ["@agenttax/mcp-server"],
      "env": {
        "AGENTTAX_API_KEY": "atx_live_your_key"
      }
    }
  }
}

After a payment:

track_payment({
  amount: 49.00,
  buyer_state: "TX",
  buyer_zip: "78701",
  description: "MCP API access — monthly subscription",
  payment_id: "pi_stripe_abc123",
  source: "stripe"
})

Returns your tax liability, compliance status, and logs it to your account. All transactions are viewable in your AgentTax dashboard.

Stripe webhook (fully automated)

For fully automatic tax tracking without calling any tool manually, point your Stripe webhook to AgentTax:

In Stripe Dashboard → Developers → Webhooks, add an endpoint:

https://agenttax.io/api/v1/webhooks/stripe?key=atx_live_YOUR_KEY

Select events: payment_intent.succeeded, checkout.session.completed, invoice.paid, charge.succeeded
Optional: set metadata.work_type on your Stripe products (compute | research | content | consulting | trading) for precise tax classification

Every payment is automatically classified, taxed, and logged. No code changes required.

Requires a billing address on the Stripe payment. Enable full address collection in your Stripe Checkout settings.

Install

Claude Code

claude mcp add agenttax -- npx @agenttax/mcp-server
export AGENTTAX_API_KEY=atx_live_your_key

Claude Desktop / Cursor / Windsurf

Add to your MCP config file:

{
  "mcpServers": {
    "agenttax": {
      "command": "npx",
      "args": ["@agenttax/mcp-server"],
      "env": {
        "AGENTTAX_API_KEY": "atx_live_your_key"
      }
    }
  }
}

Demo mode works without a key (50 calls/day, no account required). Tools marked "Yes" below need AGENTTAX_API_KEY.

Tools

Tool	What it does	Key needed
`track_payment`	Log a payment you received and get your sales tax liability. The main tool for paid MCP servers and APIs.	Demo works; key for history
`calculate_tax`	Full sales/use tax calculation with jurisdiction breakdown, audit trail, confidence score and advisories	Demo works; key for full response
`ingest_transactions`	Bulk-log up to 100 transactions (e.g. x402 purchases), idempotent on `external_tx_id`	Yes
`list_transactions`	Your transaction history with running totals	Yes
`get_nexus_thresholds`	Each state's economic nexus thresholds (revenue / transaction count), notes and DOR source	No
`get_nexus`	The states you have configured nexus in	Yes
`configure_nexus`	Set the states you have nexus in (merge semantics)	Yes
`log_trade`	Log a buy/sell; sells return realized gain/loss with cost basis	Yes
`list_trades`	Trades you have logged	Yes
`export_1099_da`	Draft Form 1099-DA payload for realized digital-asset gains	Yes (Pro)
`get_rates`	State sales tax rates and digital-goods taxability, all 51 jurisdictions or one	No
`get_local_rate`	Combined state + local rate for a zip code	No
`get_capital_gains_rates`	State short/long-term capital gains rates	No
`get_pricing`	Machine-readable pricing contract	No
`check_health`	API health and endpoint list	No

Read-only tools carry the MCP readOnlyHint annotation so clients can auto-approve them.

track_payment

track_payment({
  amount: 49.00,
  buyer_state: "TX",
  buyer_zip: "78701",
  description: "MCP tool subscription",
  work_type: "content",
  payment_id: "pi_stripe_abc123",
  source: "stripe"
})

Returns tax_owed, tax_rate, taxable, transaction_id, a classification (where the work type came from) and a compliance_note. Sellers get $0 in states where no nexus is configured; the response says so in nexus_warning.

Pass work_type explicitly (compute | research | information_service | content | consulting | trading) when you know what you sold. It is a declaration and gives the exact answer, and it is the only way the consulting or trading exemption applies: for example, AI consulting sold to an Arizona buyer is an exempt professional service (A.R.S. §42-5061(A)(1), TPR 93-48), so work_type: "consulting" returns $0 in AZ. Without work_type the server guesses from description, but a guess never takes the consulting or trading exemption: a description that looks like consulting (e.g. "SOC 2 audit platform subscription") or trading is taxed as SaaS, and classification.note tells you to resend with work_type if the guess was right. A description that looks like compute or research keeps the 1.1.1 classification, which can tax less than SaaS in some states (e.g. CT, MD, SC, TN, WV); pass work_type for an exact answer. Leave is_b2b out when you don't know the buyer; false declares a consumer. Upgrading from 1.1.1? Some track_payment results change; see CHANGELOG.md.

calculate_tax

calculate_tax({
  role: "buyer",
  amount: 500,
  buyer_state: "TX",
  buyer_zip: "78701",
  transaction_type: "compute",
  work_type: "compute",
  counterparty_id: "seller-agent-123",
  is_b2b: true
})

Optional fields: seller_state / seller_zip (origin-sourced intrastate sales in TX, UT, AZ, TN and some OH sales), use_context (Maryland B2B), digital_content_type (with transaction_type: "digital_good"), seller_remitting. transaction_type and work_type are sent exactly as given and treated as declared facts; don't guess them (consulting is exempt in Arizona).

Nexus

get_nexus_thresholds({ state: "NY" })          // what triggers registration
configure_nexus({ nexus: { TX: { hasNexus: true, reason: "Economic nexus" } } })
get_nexus()                                     // what you have configured

Capital gains and 1099-DA

log_trade({ asset_symbol: "ETH", trade_type: "buy", quantity: 2, price_per_unit: 2500, asset_class: "crypto" })
log_trade({ asset_symbol: "ETH", trade_type: "sell", quantity: 1, price_per_unit: 3100, asset_class: "crypto" })
export_1099_da({ year: 2026 })                  // draft, not a filed return

Get an API Key

curl -X POST https://agenttax.io/api/v1/auth/signup \
  -H "Content-Type: application/json" \
  -d '{"email": "you@example.com", "password": "securepass", "agent_name": "my-mcp-server", "agent_work_type": "compute"}'

All four fields are required; agent_work_type is one of compute, research, information_service, content, consulting, trading. Save the api_key.key from the response — it's only shown once.

Pricing

Tier	Price	Calls/month
Free	$0	1,500
Starter	$25/mo	10,000
Growth	$99/mo	100,000
Pro	$199/mo	1,000,000
x402	$0.005/call in USDC on Base	Pay per call, no signup

Current machine-readable pricing: get_pricing or GET https://agenttax.io/api/v1/pricing.

License

MIT