MCP server for accounting: any AI client, the same rules

Guliel's MCP server lets Claude, ChatGPT, Copilot or any other client that speaks the Model Context Protocol work in your books. Guliel is accounting and finance-operations software that runs invoicing, expenses, purchasing, payroll, reporting and a double-entry general ledger on one engine, and each operation on that engine is an MCP tool. The AI connects through OAuth 2.1, reaches only the organisations you approve, and acts within your role and the scopes you grant. The engine applies the same rules to it as to a person: numbering at issue, totals from line items, country document rules and balanced double entries.

Status. Live: the hosted MCP server at https://app.guliel.com/api/mcp/sse, the @guliel/mcp-server stdio bridge for local clients, OAuth 2.1 with PKCE, API keys for headless agents, and a public tool catalog. Planned: a sign-off queue where an accountant approves AI work. Billing is not live, so plan prices on this page are published prices and paid plans are not on sale yet.

What MCP is

The Model Context Protocol is an open standard, introduced by Anthropic, for connecting AI clients to outside systems. The client asks the server which tools it has, calls them with typed arguments and gets structured results back. Each tool has a name, an input schema and an output schema, so nothing is scraped or guessed.

In Guliel, an AI can list unpaid invoices, draft a credit memo, record a bill as an expense with the PDF attached, raise a purchase order or run a trial balance, whichever AI vendor you use.

What an AI client can do

There is one tool per API operation: every route of the REST API except the platform-admin and support-ticket routes. Tool names follow <feature>_<verb>, for example invoices_list. The full catalog, with input and output schemas, is public at /api/mcp/tools.

Tool group What the tools do
invoices_* Draft and issue invoices, receipts, invoice-receipts, payment requests, credit and debit memos as PDF in the formats of 39 countries; email them; record payments; cancel or void
expenses_* Create expenses with up to five PDF or image attachments, scan receipts, set categories, move expenses through review
accounting_* Read ledger postings, export the ledger as CSV, create and delete manual journal entries, set the books lock date
reports_* Run reports from the 49 definitions, including trial balance, balance sheet, general ledger, income statement and cash flow
customers_*, suppliers_* Customer and supplier records, supplier invitations
orders_* Purchase orders you send, and the ones your clients send you
logistics_* Items, stock levels and stock movements
payroll_*, hr_*, attendance_* Payroll runs and payslips, employee records, leave and attendance
automations_* Build, test and enable automations that keep running after the chat ends
imports_*, organizations_*, settings_* Morning, uniform-file and spreadsheet imports; organisation and workspace settings

In clients that render MCP Apps, nine tools also return an interactive view, such as the document list, an invoice, a report or stock levels.

The same rules for an AI as for a person

Every tool call runs the same API route that a click in the app runs, with the same checks:

  • A journal entry posts only if debits equal credits, every leg uses an account from the chart, and its date falls after the books lock date. An unbalanced entry is rejected with both totals in the error.
  • A document gets its number when it is issued, not when it is drafted. An issued document is checked against its country's rules, and its totals come from the line items.
  • An expense reaches the ledger only after it is approved. Approving one out of review takes the manager role, and no one can approve an expense that lacks an official invoice or receipt number and its source document.
  • Voiding an issued document and moving the books lock date both take the manager role.
  • API keys and OAuth grants can only be created or revoked from a signed-in browser session, so an AI cannot give itself more access.

There is no approval step between an AI and a write today. With invoices:write and a contributor role or above, an AI can issue invoices; grant read scopes only to keep issuing with a person. A sign-off queue where an accountant approves AI work is planned. See how Guliel works with accountants.

Access: OAuth 2.1, scopes and roles

  • Interactive clients (Claude Code, Claude Desktop, ChatGPT, Cursor) use OAuth 2.1: authorization code with PKCE (S256), dynamic client registration and .well-known discovery. On the consent screen you pick the organisations the AI may reach and can narrow the scopes it asked for.
  • Scopes are <feature>:read or <feature>:write. A scope never lifts your role: each route's role floor still applies, so a viewer cannot issue documents and a contributor cannot void them.
  • Tokens. Access tokens last 24 hours for public clients and 1 hour for confidential ones; refresh tokens last 30 days and rotate on use. Revoking an authorization in the dashboard ends every token under it.
  • Headless agents use an API key as the bearer token. A key carries its own scopes, a set of organisations or all of yours, and an optional expiry.
  • Limits and records. Each credential has its own rate limit, and every authenticated request is recorded against it. An organisation-wide audit log is planned.

Setup

Claude Code connects to the hosted endpoint:

claude mcp add --transport http --scope user guliel https://app.guliel.com/api/mcp/sse
claude mcp login guliel

Claude Desktop, Cursor and other local clients use the stdio bridge, which runs the OAuth flow on first use:

{
  "mcpServers": {
    "guliel": {
      "command": "npx",
      "args": ["-y", "@guliel/mcp-server"]
    }
  }
}

In ChatGPT, add a custom MCP connector with the URL https://app.guliel.com/api/mcp/sse; ChatGPT reads Guliel's OAuth metadata and runs the consent flow inline. Any other MCP client, including agent frameworks you host yourself, calls the same endpoint with an OAuth token or an API key. Step-by-step setup is in the MCP guide.

Where MCP fits

You do not have to move your books first. Issue documents, capture expenses and work with suppliers in Guliel beside your current tool, and export the ledger as CSV for your accountant. Automations and AI clients then take over routine steps, and you migrate the rest when ready.

Pricing

On the published price list, MCP access comes with Standard ($20 per organisation per month) and Premium ($99). Pricing is per organisation, not per seat. Billing is not live and paid plans are not on sale yet; the full table is on /pricing.

MCP calls are not metered on their own. What counts is what the tools do, such as documents issued and expenses scanned, under the same allowances as in the app. The model runs on your AI vendor's side, so connecting Claude or ChatGPT does not use the message allowance of Guliel's built-in AI companion.

Limits today

  • Guliel is not an AI model. The MCP server gives your AI client tools.
  • Documents are PDF. Structured e-invoice output such as Peppol BIS Billing is planned.
  • The chart of accounts is fixed. Custom accounts are planned.
  • Guliel does not file tax or payroll returns, through MCP or otherwise.
  • No QuickBooks, Xero, Zoho, Wave, FreshBooks, Invoice Ninja, Stripe or Shopify connector today. The imports_* tools cover Morning exports, the Israeli uniform file and the spreadsheet template; connectors for all eight are planned.

FAQ

What is the Guliel MCP server?

The Model Context Protocol endpoint of Guliel, accounting and finance-operations software with a double-entry ledger. Any MCP client connects to https://app.guliel.com/api/mcp/sse through OAuth 2.1 and gets one tool per API operation, covering documents, expenses, the ledger, reports, purchasing, stock, payroll and automations.

Which AI clients work with it?

Any client that speaks MCP. The setup guide covers Claude Code, Claude Desktop, Cursor and ChatGPT. Other clients, including Copilot and self-hosted agent frameworks, use the same HTTP endpoint or the stdio bridge.

Can an AI issue invoices without me approving them?

Yes, if you grant it. A credential with invoices:write, used by someone with the contributor role or above, can issue documents. Grant read scopes only to keep issuing with a person. A sign-off queue where an accountant approves AI work is planned.

Can an AI post to the ledger?

It can create manual journal entries with accounting:write. The engine rejects an entry whose debits and credits differ, or whose date is on or before the books lock date. Expenses reach the ledger only after approval, and approving one out of review takes the manager role.

Does the AI see other organisations' data?

No. It reaches only the organisations approved on the consent screen or attached to the API key, and every call is checked against your membership and role in that organisation.

Is MCP separate from the REST API?

No. The tool catalog is generated from the same route registry as the REST API, so each tool runs the same route with the same scope and role checks. A document an AI creates appears in the same lists as one created in the app.

Start free, then connect your AI client with the MCP guide. Plans are on /pricing.

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