Fix BC MCP proxy to target current MCP server endpoint

Microsoft moved the Business Central MCP server from
api.businesscentral.dynamics.com/v2.0/<env>/mcp to a dedicated host at
mcp.businesscentral.dynamics.com, with environment routing via HTTP
headers (TenantId, EnvironmentName, Company). The previous proxy URL
returns 400 Bad Request after a successful sign-in, even when the Azure
app registration is correctly configured.

Update both the Python (bc-mcp-proxy) and .NET (BcMCPProxy) samples:
- Default Url/BaseUrl -> https://mcp.businesscentral.dynamics.com
- Default scope -> https://mcp.businesscentral.dynamics.com/.default
- Drop the /v2.0/<env>/mcp path suffix from the request URL
- Send TenantId and EnvironmentName headers in addition to Company

Verified end-to-end against a sandbox environment: the proxy completes
the MCP initialize handshake, lists tools, and successfully invokes
List_Customers / List_Items via bc_actions_invoke.

Author: DmitryKatson

samples/BcMCPProxy/Models/ConfigOptions.cs

@@ -16,9 +16,9 @@ public  class ConfigOptions
 
         public string ClientId { get; set; } = "3acde393-18cc-4b12-803c-4c85fa111c21";
 
-        public string TokenScope { get; set; } = "https://api.businesscentral.dynamics.com/.default";
+        public string TokenScope { get; set; } = "https://mcp.businesscentral.dynamics.com/.default";
 
-        public string Url { get; set; } = "https://api.businesscentral.dynamics.com";
+        public string Url { get; set; } = "https://mcp.businesscentral.dynamics.com";
 
         public string Environment { get; set; } = "Production";
 

samples/BcMCPProxy/Runtime/MCPServerProxy.cs

@@ -43,11 +43,13 @@ public async Task RunAsync()
         var transportOptions = new HttpClientTransportOptions
         {
             Name = "Test Server",
-            Endpoint = new Uri(this.configOptions.Url.TrimEnd('/') + "/v2.0/" + this.configOptions.Environment + "/mcp"),
+            Endpoint = new Uri(this.configOptions.Url.TrimEnd('/')),
             TransportMode = HttpTransportMode.StreamableHttp,
             AdditionalHeaders = new Dictionary<string, string>
             {
-                { "Company",  HttpUtility.UrlDecode(this.configOptions.Company) },
+                { "TenantId", this.configOptions.TenantId },
+                { "EnvironmentName", this.configOptions.Environment },
+                { "Company", HttpUtility.UrlDecode(this.configOptions.Company) },
                 { "X-Client-Application", "BcMCPProxy" }
             }
         };

samples/BcMCPProxyPython/README.md

@@ -94,8 +94,8 @@ Example interactions:
 | Company | `--Company` | `BC_COMPANY` | Business Central company name | Yes |
 | Configuration Name | `--ConfigurationName` | `BC_CONFIGURATION_NAME` | Name of the Business Central configuration | No |
 | Custom Auth Header | `--CustomAuthHeader` | `BC_CUSTOM_AUTH_HEADER` | Pre-issued bearer token (skips device flow) | No |
-| Base URL | `--BaseUrl` | `BC_BASE_URL` | Base API URL (default: `https://api.businesscentral.dynamics.com`) | No |
-| Token Scope | `--TokenScope` | `BC_TOKEN_SCOPE` | OAuth scope (default: `https://api.businesscentral.dynamics.com/.default`) | No |
+| Base URL | `--BaseUrl` | `BC_BASE_URL` | MCP server URL (default: `https://mcp.businesscentral.dynamics.com`) | No |
+| Token Scope | `--TokenScope` | `BC_TOKEN_SCOPE` | OAuth scope (default: `https://mcp.businesscentral.dynamics.com/.default`) | No |
 | Log Level | `--LogLevel` | `BC_LOG_LEVEL` | Logging level (default: `INFO`) | No |
 | Debug | `--Debug` | `BC_DEBUG=1` | Enable verbose logging | No |
 

samples/BcMCPProxyPython/bc_mcp_proxy/config.py

@@ -14,8 +14,8 @@ class ProxyConfig:
 
   tenant_id: Optional[str] = None
   client_id: Optional[str] = None
-  token_scope: str = "https://api.businesscentral.dynamics.com/.default"
-  base_url: str = "https://api.businesscentral.dynamics.com"
+  token_scope: str = "https://mcp.businesscentral.dynamics.com/.default"
+  base_url: str = "https://mcp.businesscentral.dynamics.com"
   environment: str = "Production"
   company: Optional[str] = None
   configuration_name: Optional[str] = None

samples/BcMCPProxyPython/bc_mcp_proxy/proxy.py

@@ -91,6 +91,10 @@ def _build_transport_headers(config: ProxyConfig) -> dict[str, str]:
   headers: dict[str, str] = {
       "X-Client-Application": config.server_name,
   }
+  if config.tenant_id:
+    headers["TenantId"] = config.tenant_id
+  if config.environment:
+    headers["EnvironmentName"] = config.environment
   if config.company:
     headers["Company"] = unquote(config.company)
   if config.configuration_name:
@@ -99,8 +103,7 @@ def _build_transport_headers(config: ProxyConfig) -> dict[str, str]:
 
 
 def _build_endpoint_url(config: ProxyConfig) -> str:
-  base = config.base_url.rstrip("/")
-  return f"{base}/v2.0/{config.environment}/mcp"
+  return config.base_url.rstrip("/")
 
 
 def run_sync(config: ProxyConfig) -> None: