ac828d5a82
Bring the Server implementation up to date with the spec by renaming ServerConnection to ServerSession. Also update variable names, which were in various states of disarray from the multiple renamings of this type. Change-Id: I4aec883db6d0500fb91e6daa51b702614877cf8a Reviewed-on: https://go-review.googlesource.com/c/tools/+/672655 Auto-Submit: Robert Findley <rfindley@google.com> TryBot-Bypass: Robert Findley <rfindley@google.com> Commit-Queue: Robert Findley <rfindley@google.com> Reviewed-by: Jonathan Amsterdam <jba@google.com>
133 lines
4.1 KiB
Markdown
133 lines
4.1 KiB
Markdown
# MCP package
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[](https://pkg.go.dev/github.com/modelcontextprotocol/go-sdk/mcp)
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The mcp package provides an SDK for writing [model context protocol](https://modelcontextprotocol.io/introduction)
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clients and servers. It is a work-in-progress. As of writing, it is a prototype
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to explore the design space of client/server transport and binding.
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## Installation
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The mcp package is currently internal and cannot be imported using `go get`.
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## Quickstart
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Here's an example that creates a client that talks to an MCP server running
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as a sidecar process:
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```go
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package main
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import (
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"context"
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"log"
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"os/exec"
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"github.com/modelcontextprotocol/go-sdk/mcp"
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)
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func main() {
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ctx := context.Background()
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// Create a new client, with no features.
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client := mcp.NewClient("mcp-client", "v1.0.0", nil)
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// Connect to a server over stdin/stdout
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transport := mcp.NewCommandTransport(exec.Command("myserver"))
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if err := client.Connect(ctx, transport, nil); err != nil {
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log.Fatal(err)
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}
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// Call a tool on the server.
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if content, err := client.CallTool(ctx, "greet", map[string]any{"name": "you"}); err != nil {
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log.Printf("CallTool returns error: %v", err)
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} else {
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log.Printf("CallTool returns: %v", content)
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}
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}
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```
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Here is an example of the corresponding server, connected over stdin/stdout:
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```go
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package main
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import (
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"context"
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"github.com/modelcontextprotocol/go-sdk/mcp"
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)
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type HiParams struct {
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Name string `json:"name"`
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}
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func SayHi(ctx context.Context, cc *mcp.ServerSession, params *HiParams) ([]mcp.Content, error) {
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return []mcp.Content{
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mcp.TextContent{Text: "Hi " + params.Name},
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}, nil
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}
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func main() {
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// Create a server with a single tool.
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server := mcp.NewServer("greeter", "v1.0.0", nil)
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server.AddTools(mcp.MakeTool("greet", "say hi", SayHi))
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// Run the server over stdin/stdout, until the client diconnects
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_ = server.Run(context.Background(), mcp.NewStdIOTransport(), nil)
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}
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```
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## Core Concepts
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The mcp package leverages Go's [reflect](https://pkg.go.dev/reflect) package to
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automatically generate the JSON schema for your tools / prompts' input
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parameters. As an mcp server developer, ensure your input parameter structs
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include the standard `"json"` tags (as demonstrated in the `HiParams` example).
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Refer to the [jsonschema](https://www.google.com/search?q=internal/jsonschema/infer.go)
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package for detailed information on schema inference.
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### Tools
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Tools in MCP allow servers to expose executable functions that can be invoked by clients and used by LLMs to perform actions. The server can add tools using
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```go
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...
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server := mcp.NewServer("greeter", "v1.0.0", nil)
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server.AddTools(mcp.MakeTool("greet", "say hi", SayHi))
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...
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```
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### Prompts
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Prompts enable servers to define reusable prompt templates and workflows that clients can easily surface to users and LLMs. The server can add prompts by using
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```go
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...
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server := mcp.NewServer("greeter", "v0.0.1", nil)
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server.AddPrompts(mcp.MakePrompt("greet", "", PromptHi))
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...
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```
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### Resources
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Resources are a core primitive in the Model Context Protocol (MCP) that allow servers to expose data and content that can be read by clients and used as context for LLM interactions.
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<!--TODO(rfindley): Add code example for resources.-->
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Resources are not supported yet.
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## Testing
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To test your client or server using stdio transport, you can use local
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transport instead of creating real stdio transportation. See [example](server_example_test.go).
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To test your client or server using sse transport, you can use the [httptest](https://pkg.go.dev/net/http/httptest)
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package. See [example](sse_example_test.go).
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## Code of Conduct
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This project follows the [Go Community Code of Conduct](https://go.dev/conduct).
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If you encounter a conduct-related issue, please mail conduct@golang.org.
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## License
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Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the [LICENSE](../../LICENSE) file.
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Upon a potential move to [modelcontextprotocol](https://github.com/modelcontextprotocol), the license will be updated to the MIT License, and the license header will reflect the Go MCP SDK Authors.
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