Hamr
The Go framework for building MCP servers. Your struct tags are your schema.
What is Hamr?
Hamr is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to go framework for building mcp servers. your struct tags are your schema.
The Go framework for building MCP servers. Your struct tags are your schema.
This server falls under the Developer Tools category on MCPgee, the world's largest MCP server directory with 33,000+ servers.
Features
- The Go framework for building MCP servers. Your struct tags
Use Cases
Maintainer
Works with
Installation
Manual Installation
npx hamrConfiguration
Configuration Details
claude_desktop_config.json
Performance
Response Metrics
Resource Usage
How to Set Up and Use Hamr
Hamr is a Go framework that dramatically simplifies building MCP servers by turning Go struct tags into JSON Schema definitions automatically. Instead of writing verbose protocol boilerplate, you annotate your Go structs with tags like 'desc', 'default', 'enum', 'min', and 'max', and Hamr generates all the MCP tool schemas for you. It also ships a CLI with commands for scaffolding new projects, hot-reload development, and validation, making it the fastest path from idea to a working MCP server in Go.
Prerequisites
- Go 1.21 or later installed (check with 'go version')
- An MCP client such as Claude Desktop to test your server
- Basic familiarity with Go structs and struct tags
- Git installed for cloning or go install to fetch the CLI
Install the Hamr CLI
Install the hamr command-line tool globally using go install. This gives you the 'hamr' command for scaffolding and managing MCP server projects.
go install github.com/AKhilRaghav0/hamr/cmd/hamr@latestScaffold a new MCP server project
Use the 'hamr init' command to generate a complete starter project with example tools and the correct directory structure. Replace 'my-server' with your project name.
hamr init my-server
cd my-serverAdd Hamr as a dependency in an existing project
If you want to add MCP server capabilities to an existing Go module, use go get instead of scaffolding a new project.
go get github.com/AKhilRaghav0/hamrRun the server in development mode
Start your MCP server with hot-reload using 'hamr dev'. This watches for file changes and restarts the server automatically, ideal during development.
hamr devBuild and register the server with Claude Desktop
Build your server binary and add its absolute path to the Claude Desktop MCP config. The server communicates via stdio, so no port configuration is needed.
go build -o my-server .
# Then add to ~/Library/Application Support/Claude/claude_desktop_config.jsonConfigure Claude Desktop to use your built server
Edit the Claude Desktop configuration file to point to your compiled binary. Use the absolute path to the built executable.
{
"mcpServers": {
"my-server": {
"command": "/absolute/path/to/my-server"
}
}
}Hamr Examples
Client configuration
Claude Desktop configuration pointing to a locally compiled Hamr-based MCP server binary.
{
"mcpServers": {
"my-hamr-server": {
"command": "/Users/yourname/go/bin/my-server"
}
}
}Prompts to try
After connecting a Hamr server with pre-built toolboxes, try these prompts with Claude.
- "List the files in the current directory using the filesystem tools."
- "Run a git status and show me what files have changed."
- "Execute a SELECT query against the connected database and show me the results."
- "Make an HTTP GET request to https://api.example.com/data and parse the response."
- "Validate my MCP server configuration for common mistakes."Troubleshooting Hamr
'hamr: command not found' after running go install
Ensure your Go bin directory is in your PATH. Run 'export PATH=$PATH:$(go env GOPATH)/bin' and add that line to your shell profile (~/.zshrc or ~/.bashrc). Then try 'hamr --version'.
Claude Desktop does not detect the MCP server
Use the absolute path to the binary in the config (not a relative path). Verify the binary is executable with 'chmod +x /path/to/my-server' and test it directly by running it in a terminal to confirm it starts without errors.
hamr dev exits immediately or fails to watch files
Ensure you are running 'hamr dev' from the root of your project directory where the Go files reside. Check that your Go source files compile without errors first by running 'go build .' separately.
Frequently Asked Questions about Hamr
What is Hamr?
Hamr is a Model Context Protocol (MCP) server that go framework for building mcp servers. your struct tags are your schema. It connects AI assistants to external tools and data sources through a standardized interface.
How do I install Hamr?
Follow the installation instructions on the Hamr GitHub repository. Clone the repo, install dependencies, and add the server config to your AI client.
Which AI clients work with Hamr?
Hamr works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.
Is Hamr free to use?
Yes, Hamr is open source and available under the MIT license. You can use it freely in both personal and commercial projects.
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Browse More Developer Tools MCP Servers
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Quick Config Preview
Add this to your claude_desktop_config.json or .cursor/mcp.json
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