02-first-client

A small .NET 9 console client that demonstrates starting a local MCP-compatible server via stdio, connecting with the ModelContextProtocol client, listing available tools, and invoking the "multiply" tool.

Prerequisites

• .NET SDK 9.0 or later (https://dotnet.microsoft.com/download)
• The companion server project built (../01-first-server)
• Git (optional)

Overview

Program.cs:

• Loads configuration from environment variables and user secrets.
• Creates a StdioClientTransport configured with a Command pointing to the server executable.
• Starts an McpClient, lists available tools, and calls the "multiply" tool with inputs a=5 and b=7.
• Prints the tool result to the console.

Build

From the repository root, build both projects (debug):

# build the server first (adjust path if you renamed the server folder)
cd 01-first-server
dotnet build -c Debug

# then build the client
cd ../02-first-client
dotnet build -c Debug

Configure the client

By default Program.cs uses a placeholder path: Command = "/mcp-workshop/01-first-server/bin/Debug/net9.0/01-first-server"

Update Program.cs to point to the built server executable (absolute path), or modify the transport initialization to read the command path from an environment variable or user secret. Example (bash):

export MCP_SERVER_CMD="/full/path/to/01-first-server/bin/Debug/net9.0/01-first-server"
# or edit Program.cs to replace the placeholder with the above path

On Unix/macOS ensure the server binary has execute permissions:

chmod +x /full/path/to/01-first-server/bin/Debug/net9.0/01-first-server

Run

Run the client from the repository root or the project folder:

dotnet run --project 02-first-client

The client will start the configured server via stdio, enumerate tools, and invoke the "multiply" tool. Expected console output includes the connected tool(s) and a line similar to: Result: 35

Troubleshooting

• If the client fails to start the server, verify the Command path and execution permissions.
• Check that the server was built for net9.0 and the path matches the built binary location.
• Use dotnet --info to confirm the installed SDK version.
• If configuration is missing (API keys, secrets), set environment variables or user secrets as appropriate; Program.cs reads both sources.

Project structure

• Program.cs — application entry point (connects to MCP server and demonstrates a tool call)
• README.md — this file
• Other source files under the project folder

Contributing

Open an issue or submit a PR with improvements or fixes.

License

Specify the project license here (e.g., MIT).