Updated mcp tools doc

Author: ramsrib

fern/tools/mcp.mdx

@@ -64,14 +64,17 @@ Now, add the MCP tool to your assistant:
 
 ## How MCP Works
 
-The MCP integration follows these steps during a call:
-
-1. When a call starts, Vapi connects to your configured MCP server using **Streamable HTTP** protocol by default
-2. The MCP server returns a list of available tools and their capabilities
-3. These tools are dynamically added to your assistant's available tools
-4. The assistant can then use these tools during the call
-5. When a tool is invoked, Vapi sends the request to the MCP server
-6. The MCP server executes the action and returns the result
+The MCP integration follows these steps during a call or chat session:
+
+1. When a call or chat starts, Vapi connects to your configured MCP server using **Streamable HTTP** protocol by default, fetches the list of available tools, and dynamically adds them to your assistant's available tools
+2. The assistant can then use these tools during the interaction
+3. **Each time the model invokes a specific MCP tool**, Vapi creates a new connection to the MCP server and sends the request with the `X-Call-Id`/`X-Chat-Id` header to identify the call or chat
+4. The MCP server executes the action and returns the result
+5. This process repeats for every tool invocation, meaning **multiple MCP sessions are created per call or chat**
+
+<Note>
+  Vapi uses multiple MCP sessions throughout a single conversation to ensure consistent behavior across both calls and chat interactions. Each tool execution creates a separate connection to the MCP server, allowing for isolated and reliable tool execution. All tool invocations include the `X-Call-Id`/`X-Chat-Id` header to identify the specific call or chat.
+</Note>
 
 <Note>
   The MCP tool itself is not meant to be invoked by the model. It serves as a configuration mechanism for Vapi to fetch and inject the specific tool definitions from the MCP server into the model's context.