hamr

Overview

hamr is a minimalist Go framework for building MCP servers that eliminates boilerplate code by automatically generating JSON schemas from Go struct tags. It provides a higher-level abstraction than the official Go SDK with features like tool grouping, minimal schemas mode, response truncation, cost tracking, and middleware support. The framework is particularly focused on reducing token overhead in AI conversations, making it ideal for production use where efficiency matters.

Try asking AI

After installing, here are 5 things you can ask your AI assistant:

• searchfunc(ctx context.Context, input SearchInput) (string, error)

  Search for information

  Try:Search for information about Go frameworksTry:Find recent articles about AI toolsTry:Look up documentation for struct tags
• read_filefunc(ctx context.Context, input ReadFileInput) (string, error)

  Read a file from the filesystem

  Try:Read the contents of config.jsonTry:Show me the main.go fileTry:Display the README.md file
• write_filefunc(ctx context.Context, input WriteFileInput) (string, error)

  Write content to a file

  Try:Create a new file called notes.txtTry:Save the data to output.jsonTry:Write to file /path/to/file
• list_dirfunc(ctx context.Context, input ListDirInput) (string, error)

  List directory contents

  Try:List files in the current directoryTry:Show all files in /home/userTry:What's in the project folder?
• queryfunc(ctx context.Context, input QueryInput) (string, error)

  Run a SELECT query against the database

  Try:Query the database for all usersTry:Find customers from last monthTry:Get the top 10 products by sales
• list_tablesfunc(ctx context.Context, input ListTablesInput) (string, error)

  List available database tables

  Try:Show all tables in the databaseTry:What tables exist in the schema?Try:List the available tables
• http_getfunc(ctx context.Context, input HTTPGetInput) (string, error)

  Make an HTTP GET request to a URL

  Try:Get the contents of https://api.example.com/dataTry:Fetch a webpageTry:Retrieve JSON from an API endpoint
• http_postfunc(ctx context.Context, input HTTPPostInput) (string, error)

  Make an HTTP POST request to a URL

  Try:Post data to https://api.example.com/submitTry:Send a JSON payload to an endpointTry:Submit a form via HTTP POST
• run_commandfunc(ctx context.Context, input RunCommandInput) (string, error)

  Run a shell command in a sandboxed environment

  Try:Run the command 'ls -la'Try:Execute 'git status'Try:Run 'go build'
• git_statusfunc(ctx context.Context, input GitStatusInput) (string, error)

  Show the current git repository status

  Try:What's the current git status?Try:Show me uncommitted changesTry:Check the working directory
• git_difffunc(ctx context.Context, input GitDiffInput) (string, error)

  Show the differences between files

  Try:Show the diff of the last commitTry:Compare file.txt with the version in main branchTry:What changes were made in this pull request?
• git_logfunc(ctx context.Context, input GitLogInput) (string, error)

  Show commit history

  Try:Show the last 10 commitsTry:What commits were made last week?Try:Display the commit history

Comparable tools

Installation

go install github.com/AKhilRaghav0/hamr/cmd/hamr@latest

hamr init my-server
cd my-server
go run .

go get github.com/AKhilRaghav0/hamr

{
  "mcpServers": {
    "my-server": {
      "command": "go",
      "args": ["run", "/path/to/my-server"]
    }
  }
}

FAQ

How does hamr differ from the official Go SDK?

hamr is a higher-level framework built on top of the official SDK, focusing on ergonomics and token optimization. It offers automatic schema generation, tool grouping, middleware, and built-in optimization features like minimal schemas and response truncation that the SDK doesn't provide.

Can I use hamr if I need the latest MCP protocol features?

The official Go SDK will always be first to get new protocol features. hamr is best for use cases where token optimization and developer productivity are priorities, not for bleeding-edge protocol support.

Compare hamr with