business-central-mcp

Overview

Related MCP server: Dynamics 365 Business Central Admin MCP Server

Install

VSCode

Click the badge. VSCode opens and prompts for your BC URL, username, and password, then writes the configured entry to your user mcp.json.

Workspace: create .vscode/mcp.json:

{
  "servers": {
    "business-central": {
      "command": "npx",
      "args": ["-y", "business-central-mcp"],
      "env": {
        "BC_BASE_URL": "http://your-bc-server/BC",
        "BC_USERNAME": "your-user",
        "BC_PASSWORD": "your-password"
      }
    }
  }
}

Claude Code

claude mcp add business-central \
  -e BC_BASE_URL=http://your-bc-server/BC \
  -e BC_USERNAME=you \
  -e BC_PASSWORD=secret \
  -- npx -y business-central-mcp

Scope it to the current project with --scope project. See claude mcp --help for scoping options.

Claude Desktop

1. Download the latest .dxt from Releases.

2. Double-click. Claude Desktop opens Settings → Extensions and prompts for BC URL, username, and password.

3. Restart Claude Desktop.

Edit claude_desktop_config.json:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Windows: %APPDATA%\Claude\claude_desktop_config.json

• Linux: ~/.config/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "business-central": {
      "command": "npx",
      "args": ["-y", "business-central-mcp"],
      "env": {
        "BC_BASE_URL": "http://your-bc-server/BC",
        "BC_USERNAME": "your-user",
        "BC_PASSWORD": "your-password"
      }
    }
  }
}

Restart Claude Desktop.

Configuration

On-prem containers: set BC_APPLICATION_ID=NAV

If sign-in and the WebSocket upgrade both succeed but the session dies at OpenSession with NavCancelCredentialPromptException, the server is rejecting the default applicationId (FIN). On-prem BcContainerHelper containers (the onprem artifact type) generally expect NAV:

BC_APPLICATION_ID=NAV

The failure is misleading because authentication and the /csh upgrade complete first (you get a 101); BC only rejects the applicationId inside the OpenSession RPC body. SaaS and cronus images keep the FIN default. Verified against BC 27.1 onprem (see issue #10).

What can it do?

How it works

This server speaks BC's internal WebSocket protocol directly -- the same protocol the browser-based web client uses. It was reverse-engineered from decompiled BC server assemblies. No OData endpoints, no SOAP services, no Selenium.

One WebSocket connection per session. All operations serialized through a promise queue. BC27 and BC28 are wire-compatible.

LLM (Claude / Copilot / etc.)
   |
   v   MCP (stdio or HTTP)
business-central-mcp
   |
   v   WebSocket + JSON-RPC
BC Web Service Tier (BC27 / BC28)
   |
   v   internal calls
BC Server

bc_open_page returns the page as a flat list of sections:

{
  "pageContextId": "session:page:21:abc",
  "pageType": "Card",
  "caption": "Customer Card",
  "isModal": false,
  "sections": [
    { "sectionId": "header",                       "kind": "header",  "fields": [...], "actions": [...] },
    { "sectionId": "factbox:Customer Statistics",  "kind": "factbox", "fields": [...] }
  ]
}

Each section carries its own content shape:

• Card-style (header on Card pages, factbox, requestPage): fields[] and (for header) actions[]

• List-style (lines on Documents, header on List pages, repeater subpages): rows[] and totalRowCount

• Cue tiles (Role Center hosted CardParts): cues[] with each tile's name, value, groupCaption, synopsis, hasAction. Drill down with bc_execute_action { section, cue }.

bc_read_data returns a single Section for the requested sectionId (defaults to "header"). The section ID for a FactBox or subpage comes from the bc_open_page response.

• Automatic reconnect with exponential backoff after session death

• Handles BC's ~15s NTLM auth slot hold after crashes

• Auto-dismisses license popups on fresh databases

• Invoke timeout kills hung sessions and triggers recovery

• Auto-recovery from LogicalModalityViolationException mid-session: reconciles the modal stack and retries transparently; falls back to session reset when BC keeps a confirm dialog sticky

Key files

Development

git clone https://github.com/SShadowS/business-central-mcp
cd business-central-mcp
npm install
npm run start:stdio-direct   # Run from source
npm test                     # 284 unit + protocol tests
npm run test:integration     # 111 integration tests against real BC (requires running BC server)

Roadmap

OAuth, Cursor support, an interactive init wizard, and a few protocol gaps. See ROADMAP.md for the full list and priorities.

Author: Torben Leth (sshadows@sshadows.dk) License: MIT (see LICENSE)