Banana Accounting MCP Server

A Model Context Protocol (MCP) server, written in TypeScript, that exposes the Banana Accounting Plus Integrated Web Server API V2 to LLMs. Point your MCP-capable client (Claude Desktop, Cursor, etc.) at this server and the model can read your accounts, balances, journals, reports and VAT data — and create new accounting files — directly from your locally running Banana Accounting instance.

Every documented endpoint from the API V2 Get Data and Send Data references is exposed as a dedicated tool. See the full tool reference below.

The Banana Integrated Web Server is read-only for existing files — for security it cannot modify an open accounting file. The only write operation it offers is creating a new file (which Banana opens for you to review). This server mirrors that capability faithfully.

Requirements

• Node.js >= 18 (uses the built-in global fetch).
• Banana Accounting Plus 10.1.7+ with the Advanced plan (the Web Server feature requires it).
• The Integrated Web Server enabled and reachable (see below).

Enabling the Banana Web Server

1. In Banana Accounting Plus: Tools → Program Options → General, check Start Web Server (on macOS also Start Web Server with SSL — see the macOS setup guide).
2. Edit httpconfig.ini and set an accessToken under the [Banana] section, and set accessControlAllowOrigin=* (see Web Server security). To locate the file: Tools → Program Options → Advanced → System info → Web Server → Settings file path → Open path.
3. Restart Banana Accounting Plus.

Default base URLs:

| Platform | Base URL | | --- | --- | | Windows (plain HTTP) | http://127.0.0.1:8081 | | macOS (SSL) | https://127.0.0.1:8089 |

Authentication uses the X-Banana-Access-Token HTTP header. A wrong/missing token returns 401 unauthorized.

See the official docs: Integrated Web Server, Setup (macOS), API V2 Get Data, and API V2 Send Data.

Installation

The published package is @axlabs/banana-mcp-server. You usually don't need to install it explicitly — MCP clients can run it on demand with npx:

npx -y @axlabs/banana-mcp-server

Or install it globally to get the banana-mcp-server command:

npm install -g @axlabs/banana-mcp-server
banana-mcp-server

To build from source instead:

npm install
npm run build

Configuration

The server is configured entirely through environment variables:

| Variable | Default | Description | | --- | --- | --- | | BANANA_BASE_URL | http://127.0.0.1:8081 | Base URL of the Banana web server (no trailing slash). | | BANANA_ACCESS_TOKEN | (empty) | Access token from httpconfig.ini. Sent as X-Banana-Access-Token. | | BANANA_DEFAULT_DOC | (none) | Optional default document name so tools can omit the doc argument. | | BANANA_TIMEOUT_MS | 30000 | Per-request timeout in milliseconds. | | BANANA_INSECURE_TLS | false | Set to true to accept the self-signed certificate used by the macOS SSL server. |

Copy .env.example to get started.

Usage

As a standalone command

BANANA_BASE_URL="http://127.0.0.1:8081" \
BANANA_ACCESS_TOKEN="my-super-secret-access-token" \
npx -y @axlabs/banana-mcp-server

(Or node dist/index.js when running from a local build.) The server speaks MCP over stdio. Diagnostic output goes to stderr so it never corrupts the JSON-RPC stream on stdout.

Claude Desktop / Cursor configuration

Add an entry to your MCP client config (e.g. Claude Desktop's claude_desktop_config.json, or .cursor/mcp.json):

{
  "mcpServers": {
    "banana": {
      "command": "npx",
      "args": ["-y", "@axlabs/banana-mcp-server"],
      "env": {
        "BANANA_BASE_URL": "http://127.0.0.1:8081",
        "BANANA_ACCESS_TOKEN": "my-super-secret-access-token"
      }
    }
  }
}

Prefer a pinned version in production, e.g. "@axlabs/[email protected]". To run a local build instead, use "command": "node" with "args": ["/absolute/path/to/banana-mcp-server/dist/index.js"].

On macOS with the SSL web server, use https://127.0.0.1:8089 and add "BANANA_INSECURE_TLS": "true" (or trust the banana.localhost certificate in Keychain Access).

How an LLM should use it

1. Call banana_list_documents to discover the open accounting files.
2. Pass the returned file name (e.g. accounting.ac2) as the doc argument to other tools — or set BANANA_DEFAULT_DOC and omit it.
3. Use the read tools to answer questions, and banana_create_document to create new files.

Conventions used throughout the API: dates are ISO 8601 (YYYY-MM-DD), decimals use a dot separator with no thousands separator (see the "Data formats" section of the docs), and previous-year files are addressed by suffixing the document name with _p1, _p2, etc. Many period arguments accept abbreviations like Q1, 3M, 1Y or explicit ranges like 2024-01-01/2024-03-31.

Tool reference

All tools are namespaced with the banana_ prefix. Reads default to JSON output where the API supports it. The read tools map to the API V2 Get Data reference; the file-creation tools map to the API V2 Send Data reference.

Application & discovery

| Tool | Endpoint | Description | | --- | --- | --- | | banana_application | /v2/application[/{value}] | App info (version, serial, OS); optionally a single field. | | banana_application_version | /v2/application/version | Application version string. | | banana_list_documents | /v2/docs | List open accounting documents. | | banana_document_requests | /v2/doc/{doc} | List available requests for a document (HTML). | | banana_table_names | /v2/doc/{doc}/tablenames | List the tables in a document. |

Tables

| Tool | Endpoint | Description | | --- | --- | --- | | banana_table | /v2/doc/{doc}/table/{table} | Read a table (view/columns/format). | | banana_table_rowcount | .../rowcount | Number of rows in a table. | | banana_table_columns | .../columnnames | Column XML names of a table. | | banana_cell | .../row/{row}/column/{col} | A single cell value (row number or Account=1000). | | banana_rowlist_names | .../rowlistnames | Named row lists of a table. | | banana_rowlist | .../rowlist/{name} | Read a named row list. | | banana_rowlist_rowcount | .../rowlist/{name}/rowcount | Row count of a row list. | | banana_rowlist_cell | .../rowlist/{name}/row/{row}/column/{col} | A cell within a row list. |

Chart of accounts

| Tool | Endpoint | Description | | --- | --- | --- | | banana_accounts | /v2/doc/{doc}/accounts | List accounts. | | banana_account_description | /v2/doc/{doc}/accountdescription/{acc\|Gr=id}[/{col}] | Account/group description. | | banana_groups | /v2/doc/{doc}/groups | List groups. | | banana_segments | /v2/doc/{doc}/segments | List segments. | | banana_vatcodes | /v2/doc/{doc}/vatcodes | List VAT codes. | | banana_vat_description | /v2/doc/{doc}/vatdescription/{code}[/{col}] | VAT code description. |

Balances, budget, interest & projection

| Tool | Endpoint | Description | | --- | --- | --- | | banana_balance | /v2/doc/{doc}/balance/{acc}/{type} | Current balance figure. | | banana_budget | /v2/doc/{doc}/budget/{acc}/{type} | Budget figure. | | banana_interest | /v2/doc/{doc}/interest/{acc} | Calculated interest (requires rate). | | banana_budget_interest | /v2/doc/{doc}/budgetinterest/{acc} | Interest on budget transactions. | | banana_projection | /v2/doc/{doc}/projection/{acc}/{type} | Projection figure (requires projectionstart). | | banana_vat_balance | /v2/doc/{doc}/vatbalance/{code}/{type} | Current VAT balance. | | banana_vat_budget | /v2/doc/{doc}/vatbudget/{code}/{type} | Budget VAT figure. | | banana_vat_projection | /v2/doc/{doc}/vatprojection/{code}/{type} | VAT projection (requires projectionstart). |

{type} is one of opening, credit, debit, total, balance, openingcurrency, creditcurrency, debitcurrency, totalcurrency, balancecurrency, rowcount. VAT types are taxable, amount, notdeductible, posted, rowcount. The {acc} selector accepts an account id, Gr=<group>, BClass=<class>, or pipe-separated accounts like 1000|1010.

Account cards (ledgers)

| Tool | Endpoint | Description | | --- | --- | --- | | banana_account_card | /v2/doc/{doc}/accountcard/{acc} | Transactions making up an account. | | banana_budget_card | /v2/doc/{doc}/budgetcard/{acc} | Budget transactions for an account. | | banana_projection_card | /v2/doc/{doc}/projectioncard/{acc} | Projection card (requires projectionstart). | | banana_vat_card | /v2/doc/{doc}/vatcard/{code} | Account card for a VAT code. |

Reports & document metadata

| Tool | Endpoint | Description | | --- | --- | --- | | banana_accounting_report | /v2/doc/{doc}/accreport | Accounting report (with subdivision). | | banana_vat_report | /v2/doc/{doc}/vatreport | VAT report. | | banana_journal | /v2/doc/{doc}/journal | Journal of all transactions. | | banana_start_period | /v2/doc/{doc}/startperiod | Start date of accounting/period. | | banana_end_period | /v2/doc/{doc}/endPeriod | End date of accounting/period. | | banana_info_table | /v2/doc/{doc}/info | File info table. | | banana_info_value | /v2/doc/{doc}/info/{section}/{id} | A single file-info value. | | banana_infos | /v2/doc/{doc}/infos | All file infos as JSON. | | banana_messages | /v2/doc/{doc}/messages | Validation/error messages (recheck). | | banana_messages_count | /v2/doc/{doc}/messages/count | Count of error messages. |

Web-app data & system

| Tool | Endpoint | Description | | --- | --- | --- | | banana_appdata_get | GET /v2/appdata/{id} | Read stored web-app data. | | banana_appdata_put | PUT /v2/appdata/{id} | Save web-app data. | | banana_appdata_delete | DELETE /v2/appdata/{id} | Delete web-app data. | | banana_appdata_form | /v2/appdataform | HTML form to manage app data. | | banana_settings | /v2/settings | Web server settings page. | | banana_help | /v2/help | Web server help page. | | banana_file | /v2/files/{name} | Read a file from the user data folder. | | banana_run_script | /v2/script | Execute a Banana JavaScript file. | | banana_www_app | /v2/doc/{doc}/apps/{name} | Built-in WWW app (charts, dashboard). | | banana_api_js | /v2/doc/{doc}/bananaapiv2.js | The JavaScript API helper file. |

Creating files (Send Data)

| Tool | Endpoint | Description | | --- | --- | --- | | banana_create_document | POST /v2/doc?show | Create & show a new file from a high-level list of per-table row changes. | | banana_create_document_raw | POST /v2/doc?show | Post a raw { fileType, data } payload (escape hatch). |

banana_create_document accepts either an accountingType ({ docGroup, docApp, decimals } — e.g. docGroup: 100 double entry, docApp: 100 without VAT / 110 with VAT) or an ac2_base64 template plus a title, and a tables array describing the rows to add / modify / delete. Internally it builds a Banana DocumentChange envelope (see also Modify Data and the Excel Office Script example).

Development

npm run dev        # run from source with watch (tsx)
npm run typecheck  # tsc --noEmit
npm run lint       # eslint
npm test           # vitest (unit + in-memory MCP integration tests)
npm run build      # compile to dist/

Tests run fully offline against a mocked fetch and an in-memory MCP transport, so they do not require a running Banana instance.

Publishing (maintainers)

The package is published to npm as the public scoped package @axlabs/banana-mcp-server. prepublishOnly compiles the TypeScript to dist/ first.

npm version <patch|minor|major>
npm publish            # access:public is set via publishConfig

Project layout

src/
  index.ts          # stdio entry point
  server.ts         # builds the McpServer and registers tools
  config.ts         # environment configuration
  client.ts         # HTTP client for the Banana web server
  types.ts          # DocumentChange types + builder
  tools/            # one module per API area, all registered via tools/index.ts
test/               # vitest suites

License

Apache License 2.0 © AxLabs. See LICENSE and NOTICE.