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Taxjar for AI agents

TaxJar calculates and reports sales tax for online sellers, handling rates, nexus regions, and transaction records so finance teams don't calculate tax by hand. Connect it once through Arc0, and your agent, or Claude, ChatGPT and Cursor, can use it through one MCP endpoint, limited to what each user approved.

Connect TaxjarSee the 21 actions ↓
Finance and accountingAPI keyMCP + RESTtaxjar.com
AUDIT LOG · TAXJARPOLICY: acme-support
09:41:07 · claude · u_8f2read
taxjar.list_customers
List Customers✓ allowed · 212ms
09:41:08 · claude · u_8f2read
taxjar.show_customer
Show Customer✓ allowed · 164ms
09:41:09 · claude · u_8f2write
taxjar.create_customer
Create Customer✓ approved · approved by user
09:41:12 · claude · u_8f2destructive
taxjar.delete_customer
Delete Customer✕ blocked · policy: deny
EVERY TAXJAR CALL, ON THE RECORD
01 · USE CASES

What agents do in Taxjar.

01

Calculate sales tax for an order

Get the correct sales tax for a specific order based on origin, destination, and product category.

02

List nexus regions

Read which states or regions a business has tax nexus in before deciding where to file.

03

Confirm before deleting a transaction

Check with the user before deleting an order or refund transaction, since it changes tax reporting history.

02 · ACTIONS

21 Taxjar actions, graded by risk.

Every Taxjar action is tagged read, write or destructive, so one policy covers the whole app and new actions inherit the right default.

read

10

Look things up. Allowed by default.

  • taxjar.list_customers
    List Customers
  • taxjar.list_nexus_regions
    List Nexus Regions
  • taxjar.list_tax_categories
    List Tax Categories
  • taxjar.list_order_transactions
    List Order Transactions
  • taxjar.show_customer
    Show Customer
  • taxjar.validate_vat_number
    Validate VAT Number
  • taxjar.show_order_transaction
    Show Order Transaction
  • taxjar.show_tax_rates_for_a_location
    Show Tax Rates for a Location
  • taxjar.calculate_sales_tax_for_an_order
    Calculate Sales Tax For An Order
  • taxjar.summarize_tax_rates_for_all_regions
    Summarize Tax Rates for All Regions

write

4

Create and change things. Allow, or ask the user first.

  • taxjar.create_customer
    Create Customer
  • taxjar.update_customer
    Update Customer
  • taxjar.create_order_transaction
    Create Order Transaction
  • taxjar.update_order_transaction
    Update Order Transaction

destructive

7

Delete, cancel or archive. Ask first, or deny outright.

  • taxjar.delete_customer
    Delete Customer
  • taxjar.delete_order_transaction
    Delete Order Transaction
  • taxjar.delete_refund_transaction
    Delete Refund Transaction
  • taxjar.show_refund_transaction
    Show Refund Transaction
  • taxjar.list_refund_transactions
    List refund transactions
  • taxjar.create_refund_transaction
    Create Refund Transaction
  • taxjar.update_refund_transaction
    Update Refund Transaction
03 · HOW IT WORKS

Taxjar in three steps.

  1. 01Your users connect TaxjarThey add their Taxjar api key on Arc0 Connect, under your brand. It goes straight into the vault.
  2. 02You set the rulesReads run, writes like “create Customer” can wait for the user, and “delete Customer” can be denied outright.
  3. 03Any agent can actYour agent calls Taxjar through the Arc0 SDK or MCP, and so can Claude, ChatGPT and Cursor. Every call lands on the audit log.
POLICY.TS
await arc0.policies.set('taxjar', {
  read: 'allow',
  write: 'ask',        // create_customer
  destructive: 'deny',  // delete_customer
})

# Claude Code: the same connection, one URL
$ claude mcp add --transport http arc0 \
    https://mcp.arc0.ai/u/u_8f2
04 · AUTH AND DATA

How Taxjar connects.

Users add their Taxjar api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.

The same Taxjar connection serves your agent over MCP and your own backend over REST and the proxy, so a user connects once. How Arc0 handles credentials →

AUTH
API key
CREDENTIALS
Per-tenant encrypted vault
MODEL SEES
Results only, never credentials
AUDIT LOG
Every call, on every plan
05 · WORKS WITH

Use Taxjar from any agent.

Claude
ChatGPT
Cursor
Codex
VS Code
OpenAI Agents SDK
Claude Agent SDK
Vercel AI SDK
Mastra
LangGraph
06 · RELATED

More finance and accounting apps.

Stripe433 actions44API4 actionsAirwallex7 actionsAiwyn Tax10 actionsAltoviz67 actionsCoupa384 actionsZoho Books265 actionsMaxio177 actions
ALL FINANCE AND ACCOUNTING APPS →
07 · FAQ

Taxjar and Arc0, answered.

Q01

Can I use Taxjar with Claude, ChatGPT or Cursor?

Yes. Connect Taxjar to Arc0 once, then add your Arc0 MCP URL to Claude, ChatGPT, Cursor, Claude Code or any other remote-MCP client. Each assistant only gets the Taxjar actions you allow.

Q02

How do users connect Taxjar?

Users add their Taxjar api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.

Q03

Which Taxjar actions can my agent take?

21 in total: 10 read, 4 write and 7 destructive, such as “create Customer”. Your policies decide which of them each agent may call.

Q04

Can I stop my agent from deleting things in Taxjar?

Yes. Actions like “delete Customer” are graded destructive. Set destructive actions to deny, or to ask so the user approves each one, and blocked calls still show up on the audit log.

Q05

Can my own backend call Taxjar too?

Yes. The same Taxjar connection is available over REST and through the Arc0 proxy, so your product and your agent share one connection per user.

Get started

Plug Taxjar into your agent.

Your users connect Taxjar once, under your brand. Your agent gets 21 actions behind your policies, with every call on the record.

Connect TaxjarBrowse all apps →

Free to build · MCP + REST · Audit log on every plan