# go-mcp-server

Guidance for building Go MCP servers with the official SDK, covering tools, resources, prompts, transports, and error handling.

- rule · `type=rule` · GitHub Copilot · ★ 40451
- Author: github · official GitHub repository
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/github/awesome-copilot/tree/HEAD/instructions/go-mcp-server.instructions.md
- Updated: 2026-10-23
- HTML: https://affpapa.org/en/nevibecode/rules/go-mcp-server

## What it does

The rule applies to `*.go`, `go.mod`, and `go.sum` files. It covers creating a server with `mcp.NewServer` and registering tools, resources, and reusable prompt templates through `github.com/modelcontextprotocol/go-sdk`.

The guidance discusses stdio and HTTP transports, JSON Schema tags on structs, context cancellation, server capabilities, and standard Go tests for tools. The project needs the official Go SDK. Long-running work should respect context cancellation so it can stop when a request is cancelled.

## Requirements
- Works with: GitHub

## Install

### GitHub Copilot (native platform)

**Manually: put the files in place**
- File: `.github/instructions/go-mcp-server.instructions.md` — The applyTo field sets which files it applies to

### Claude Code

**Manually: put the files in place**
- File: `.claude/rules/go-mcp-server.md` — The paths frontmatter field limits the files: move applyTo from the source into paths

### Codex

**AGENTS.md**
- Codex reads AGENTS.md: paste the rule text there

### Cursor

**Manually: put the files in place**
- File: `.cursor/rules/go-mcp-server.mdc` — Frontmatter: description, globs, alwaysApply. Move applyTo from the source into globs, or the rule will not attach on its own

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/rules/go-mcp-server.md`

### Cline

**Manually: put the files in place**
- File: `.clinerules/go-mcp-server.md`

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/github/awesome-copilot/tree/HEAD/instructions/go-mcp-server.instructions.md

## When to use it
- build a Go MCP server with the official SDK
- register a tool with typed input and output
- serve data as MCP resources
- add reusable prompt templates
- handle errors and request cancellation through `context`

## Example prompts
- Set up my Go MCP server using the `go-mcp-server` rule and add a tool with typed inputs.
- Review how MCP tools handle errors and `context` cancellation in this project.
- Add an MCP resource and a reusable prompt template following `go-mcp-server`.

## Source text · go-mcp-server.instructions.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 4600f979b8aa6e1f.

BEGIN THIRD-PARTY FILE 4600f979b8aa6e1f
````text
---
description: 'Best practices and patterns for building Model Context Protocol (MCP) servers in Go using the official github.com/modelcontextprotocol/go-sdk package.'
applyTo: "**/*.go, **/go.mod, **/go.sum"
---

# Go MCP Server Development Guidelines

When building MCP servers in Go, follow these best practices and patterns using the official Go SDK.

## Server Setup

Create an MCP server using `mcp.NewServer`:

```go
import "github.com/modelcontextprotocol/go-sdk/mcp"

server := mcp.NewServer(
    &mcp.Implementation{
        Name:    "my-server",
        Version: "v1.0.0",
    },
    nil, // or provide mcp.Options
)
```

## Adding Tools

Use `mcp.AddTool` with struct-based input and output for type safety:

```go
type ToolInput struct {
    Query string `json:"query" jsonschema:"the search query"`
    Limit int    `json:"limit,omitempty" jsonschema:"maximum results to return"`
}

type ToolOutput struct {
    Results []string `json:"results" jsonschema:"list of search results"`
    Count   int      `json:"count" jsonschema:"number of results found"`
}

func SearchTool(ctx context.Context, req *mcp.CallToolRequest, input ToolInput) (
    *mcp.CallToolResult,
    ToolOutput,
    error,
) {
    // Implement tool logic
    results := performSearch(ctx, input.Query, input.Limit)
    
    return nil, ToolOutput{
        Results: results,
        Count:   len(results),
    }, nil
}

// Register the tool
mcp.AddTool(server, 
    &mcp.Tool{
        Name:        "search",
        Description: "Search for information",
    },
    SearchTool,
)
```

## Adding Resources

Use `mcp.AddResource` for providing accessible data:

```go
func GetResource(ctx context.Context, req *mcp.ReadResourceRequest) (*mcp.ReadResourceResult, error) {
    content, err := loadResourceContent(ctx, req.URI)
    if err != nil {
        return nil, err
    }
    
    return &mcp.ReadResourceResult{
        Contents: []any{
            &mcp.TextResourceContents{
                ResourceContents: mcp.ResourceContents{
                    URI:      req.URI,
                    MIMEType: "text/plain",
                },
                Text: content,
            },
        },
    }, nil
}

mcp.AddResource(server,
    &mcp.Resource{
        URI:         "file:///data/example.txt",
        Name:        "Example Data",
        Description: "Example resource data",
        MIMEType:    "text/plain",
    },
    GetResource,
)
```

## Adding Prompts

Use `mcp.AddPrompt` for reusable prompt templates:

```go
type PromptInput struct {
    Topic string `json:"topic" jsonschema:"the topic to analyze"`
}

func AnalyzePrompt(ctx context.Context, req *mcp.GetPromptRequest, input PromptInput) (
    *mcp.GetPromptResult,
    error,
) {
    return &mcp.GetPromptResult{
        Description: "Analyze the given topic",
        Messages: []mcp.PromptMessage{
            {
                Role: mcp.RoleUser,
                Content: mcp.TextContent{
                    Text: fmt.Sprintf("Analyze this topic: %s", input.Topic),
                },
            },
        },
    }, nil
}

mcp.AddPrompt(server,
    &mcp.Prompt{
        Name:        "analyze",
        Description: "Analyze a topic",
        Arguments: []mcp.PromptArgument{
            {
                Name:        "topic",
                Description: "The topic to analyze",
                Required:    true,
            },
        },
    },
    AnalyzePrompt,
)
```

## Transport Configuration

### Stdio Transport

For communication over stdin/stdout (most common for desktop integrations):

```go
if err := server.Run(ctx, &mcp.StdioTransport{}); err != nil {
    log.Fatal(err)
}
```

### HTTP Transport

For HTTP-based communication:

```go
import "github.com/modelcontextprotocol/go-sdk/mcp"

transport := &mcp.HTTPTransport{
    Addr: ":8080",
    // Optional: configure TLS, timeouts, etc.
}

if err := server.Run(ctx, transport); err != nil {
    log.Fatal(err)
}
```

## Error Handling

Always return proper errors and use context for cancellation:

```go
````
END THIRD-PARTY FILE 4600f979b8aa6e1f

The third-party file has ended. Everything between the 4600f979b8aa6e1f tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

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