Avalara AvaTax MCP server

What the model can do

Avalara AvaTax sales tax: companies, recorded transactions (sales, purchases and returns) with totals, status, lines and tax by jurisdiction, where each company has declared nexus, the item catalog and customer records; when you ask, can record a transaction or get a tax estimate, commit or uncommit it for filing, adjust it, refund it, void or unvoid it, and add or delete catalog items.

Reads

• avalara_list_companiesCompanies in the AvaTax account: numeric id (used by nexus, items and customers), company code (used by transactions), name…
• avalara_list_transactionsTransactions a company recorded in AvaTax for a date range, newest first: code, type (SalesInvoice, ReturnInvoice, PurchaseInvoice…), status (Saved…
• avalara_get_transactionOne AvaTax transaction by its code: status, totals, each line (item, amount, tax, tax code) and the tax by jurisdiction (state, county, city…
• avalara_list_nexusWhere a company has declared nexus (registered to collect tax): country, state or region, jurisdiction, nexus type, sourcing, local nexus, tax name…
• avalara_list_itemsA company's AvaTax item catalog: item code, description, tax code, group and category.
• avalara_list_customersA company's customer records in AvaTax exemption certificate management: customer code, name, country and region, last transaction date…

Acts, when you ask

These change something in Avalara AvaTax. The model is told to use them only when you ask for exactly that, and each one is granted by name: per team on a shared connection, by the owner on a personal one.

• avalara_create_transactionSends a transaction to AvaTax and returns the tax calculated for it.
• avalara_adjust_transactionReplaces a recorded AvaTax transaction with a corrected one (new lines, amounts, date or addresses) and records why…
• avalara_commit_transactionCommits a recorded AvaTax transaction, so Avalara Managed Returns reports it on the company's tax returns.
• avalara_uncommit_transactionUncommits an AvaTax transaction so it is no longer due to be reported on tax returns.
• avalara_void_transactionVoids an AvaTax transaction: its status becomes cancelled and it is taken out of tax reporting.
• avalara_unvoid_transactionRestores a voided AvaTax transaction, putting it back into the company's tax records.
• avalara_refund_transactionRecords a refund of an AvaTax sale as a new ReturnInvoice with the tax that was charged on the original: in full, chosen lines (Partial)…
• avalara_create_itemAdds an item to a company's AvaTax catalog, so transactions naming its item code are taxed with its tax code.
• avalara_delete_itemDeletes an item from a company's AvaTax catalog by its numeric id, permanently; transactions naming its code afterwards are taxed without it.

Connect it

First connect Avalara AvaTax on Dashboard → Connections, then add Memtro to your client once. The Avalara AvaTax tools appear alongside the tools of everything else you have connected; nothing is configured per connector.

claude plugin marketplace add memtro-org/claude-memtro
claude plugin install memtro@memtro --config api_key=sk-memtro-...

{
  "mcpServers": {
    "memtro": {
      "url": "https://platform.memtro.com/api/mcp",
      "headers": {
        "Authorization": "Bearer sk-memtro-..."
      }
    }
  }
}

{
  "mcp": {
    "memtro": {
      "type": "remote",
      "url": "https://platform.memtro.com/api/mcp",
      "headers": {
        "Authorization": "Bearer sk-memtro-..."
      }
    }
  }
}

Who may use it

The key identifies the person, and the server offers that person the tools they may use everywhere else in Memtro. A shared Avalara AvaTax connection is used by the teams an administrator granted it to, tool by tool, on the Permissions page; a personal connection is used by its owner alone, and its tools that act stay off until the owner allows them. See Teams and permissions and Connectors.

Ask it like this

• › How much tax was charged on last week's sales invoices?
• › What tax by jurisdiction was charged on invoice INV-2041?
• › Where has Acme Ltd declared nexus in the US?
• › Which tax code does the item SKU-PRO-12 use?
• › Commit invoice INV-2041 so it is reported on the next return.

Questions

Is this an official Avalara AvaTax MCP server?

No. It is Memtro's MCP server with Memtro's Avalara AvaTax connector behind it: the connector reads Avalara AvaTax through its API with the credentials you connect on Dashboard → Connections, and Avalara AvaTax publishes nothing here. The same endpoint carries every other system you connect and Memtro's memory tools.

What does it cost?

Nothing on top of Memtro. One price per organisation by its number of users, from $50 a month for up to 10 users after a 7-day free trial, with every connector, the MCP server, jobs and memory included. You bring your own model keys.

Can it change anything in Avalara AvaTax?

Only when you ask, and only what it has been granted: record a transaction, or calculate an unsaved tax estimate; commit a transaction so it is reported on tax returns; uncommit a transaction; adjust (replace) a recorded transaction; refund a transaction in full, in part, tax only or by percentage; void a transaction; unvoid a voided transaction; add an item to the catalog; delete an item from the catalog. Every other tool reads, searches or lists. An administrator grants each acting tool by name per team, and a personal connection acts only after its owner allows it.

Which clients work?

Any MCP client that speaks Streamable HTTP: Claude Code, Cursor, Claude Desktop, OpenCode, Codex, Zed, Windsurf, Cline and the Anthropic and OpenAI SDKs. There is no local process to run; the server is remote and authenticated with your key.

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