Skip to content

Added Sampling Example to README #698

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 5 commits into from
Jun 30, 2025
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
63 changes: 63 additions & 0 deletions README.md
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@
- [Tools](#tools)
- [Prompts](#prompts)
- [Completions](#completions)
- [Sampling](#sampling)
- [Running Your Server](#running-your-server)
- [stdio](#stdio)
- [Streamable HTTP](#streamable-http)
Expand Down Expand Up @@ -382,6 +383,68 @@ import { getDisplayName } from "@modelcontextprotocol/sdk/shared/metadataUtils.j
const displayName = getDisplayName(tool);
```

### Sampling

MCP servers can request LLM completions from connected clients that support sampling.

```typescript
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import { z } from "zod";

const mcpServer = new McpServer({
name: "tools-with-sample-server",
version: "1.0.0",
});

// Tool that uses LLM sampling to summarize any text
mcpServer.registerTool(
"summarize",
{
description: "Summarize any text using an LLM",
inputSchema: {
text: z.string().describe("Text to summarize"),
},
},
async ({ text }) => {
// Call the LLM through MCP sampling
const response = await mcpServer.server.createMessage({
messages: [
{
role: "user",
content: {
type: "text",
text: `Please summarize the following text concisely:\n\n${text}`,
},
},
],
maxTokens: 500,
});

return {
content: [
{
type: "text",
text: response.content.type === "text" ? response.content.text : "Unable to generate summary",
},
],
};
}
);

async function main() {
const transport = new StdioServerTransport();
await mcpServer.connect(transport);
console.log("MCP server is running...");
}

main().catch((error) => {
console.error("Server error:", error);
process.exit(1);
});
```


## Running Your Server

MCP servers in TypeScript need to be connected to a transport to communicate with clients. How you start the server depends on the choice of transport:
Expand Down
57 changes: 57 additions & 0 deletions src/examples/server/toolWithSampleServer.ts
Original file line number Diff line number Diff line change
@@ -0,0 +1,57 @@

// Run with: npx tsx src/examples/server/toolWithSampleServer.ts

import { McpServer } from "../../server/mcp.js";
import { StdioServerTransport } from "../../server/stdio.js";
import { z } from "zod";

const mcpServer = new McpServer({
name: "tools-with-sample-server",
version: "1.0.0",
});

// Tool that uses LLM sampling to summarize any text
mcpServer.registerTool(
"summarize",
{
description: "Summarize any text using an LLM",
inputSchema: {
text: z.string().describe("Text to summarize"),
},
},
async ({ text }) => {
// Call the LLM through MCP sampling
const response = await mcpServer.server.createMessage({
messages: [
{
role: "user",
content: {
type: "text",
text: `Please summarize the following text concisely:\n\n${text}`,
},
},
],
maxTokens: 500,
});

return {
content: [
{
type: "text",
text: response.content.type === "text" ? response.content.text : "Unable to generate summary",
},
],
};
}
);

async function main() {
const transport = new StdioServerTransport();
await mcpServer.connect(transport);
console.log("MCP server is running...");
}

main().catch((error) => {
console.error("Server error:", error);
process.exit(1);
});