Adds instructions for connecting local mcp servers (#344)

To workbench hosted assistants

docs/connect-hosted-codespace-assistant-to-local-mcp.md

@@ -0,0 +1,102 @@
+## How to connect the Codespace Assistant (hosted at semantic-workbench.azurewebsites.net) to local MCP servers
+
+NOTE: If you are running the workbench and the assistant locally, this guide will NOT help you.
+
+To connect assistants running in the hosted workbench to a local MCP server, the MCP server needs to be available as an SSE service connectable from the public internet.
+To make it accessible, you need to set up a tunnel to the localhost server.
+We recommend using the Azure devtunnel service, as it provides a simple and reliable way to create a tunnel.
+For MCP servers that only support stdio transport, you additionally need to run `mcp-proxy`, to expose the app as an HTTP/SSE service.
+
+## Standard input/output (stdio) transport
+
+If the MCP server supports SSE transport, you can skip this step.
+
+For MCP servers that only support stdio transport, you can use the mcp-proxy to expose the app as an HTTP/SSE service.
+
+### Step 1: Determine the command to run the MCP server
+
+This will be in the docs for the MCP server you are using.
+
+### Step 2: Run mcp-proxy
+
+Pick an unused port (e.g. 50001) and run the following command:
+
+```bash
+# Option 1: With uv (recommended)
+uvx mcp-proxy --sse-port={port} {command}
+
+# Option 2: With pipx (alternative)
+pipx run mcp-proxy --sse-port={port} {command}
+```
+
+Example for port 50001 and command `uvx mcp-server-fetch`:
+
+```bash
+uvx mcp-proxy --sse-port=50001 uvx mcp-server-fetch
+```
+
+## HTTP Server-Sent Events (SSE) transport
+
+For MCP servers that support HTTP/SSE transport, or servers for which you have set up the proxy, you can use the Azure devtunnel service to create a tunnel to the localhost server.
+
+### Step 1: Install [devtunnel CLI](https://learn.microsoft.com/en-us/azure/developer/dev-tunnels/get-started#install)
+
+```bash
+# Windows
+winget install Microsoft.DevTunnel
+
+# Mac
+brew install --cask devtunnel
+
+#Linux
+curl -sL https://aka.ms/DevTunnelCliInstall | bash
+```
+
+### Step 2: Log in to devtunnel
+
+```bash
+devtunnel user login
+```
+
+### Step 3: Determine which port the MCP server is running on
+
+The default port that an MCP server runs on will be in the docs for the MCP server you are using. This port will often be configurable.
+
+For servers that you have set up the proxy for, the port is the one you specified in the `--sse-port` argument when running `mcp-proxy`.
+
+### Step 4: Create a tunnel
+
+```bash
+devtunnel host -p {mcp-server-port} --allow-anonymous --protocol http
+```
+
+Example for MCP server running on port 50001:
+
+```bash
+devtunnel host -p 50001 --allow-anonymous --protocol http
+```
+
+### Step 4: Copy the tunnel URL
+
+`devtunnel` will print a URL like this:
+
+```
+Connect via browser: https://...
+```
+
+NOTE: Make sure you copy the "Connect via browser" URL, not the "Inspect network activity" URL.
+
+## Configure the Codespace Assistant
+
+1. Open the [semantic-workbench](https://semantic-workbench.azurewebsites.net) in your browser.
+1. Create a conversation with a Codespace Assistant or open an existing one.
+1. Click the "Conversation canvas" button in the top-right corner, near your profile picture.
+1. Click the "..." button next to the assistant, and click "Configure".
+1. Scroll down to the "MCP Servers" section.
+1. Delete the default MCP servers using the "Delete" button, if there are any. (They aren't accessible from the workbench and will cause errors.)
+1. Click the "+ Add" button.
+1. Update the "Key" field to give it a relevant name (e.g. "vscode" or "word").
+1. Update the "Command" field to the tunnel URL you copied in the previous step, plus `/sse`. For example, if your tunnel URL is `https://abcdefghi123.usw2.devtunnels.ms`, the command should be `https://c2z6r7s8-6010.usw2.devtunnels.ms/sse`.
+1. Click "Save".
+1. Click "Close".
+1. As a test, try asking the assistant "what tools do you have?".