---
title: "Use sampling tools only where supported"
description: "Sampling tools and toolChoice are available from MCP 2025-11-25. Earlier-version interaction examples cannot use those fields. Remove them or narrow the containing Tool's protocol "
source: "https://mcpdesc.org/docs/rules/0.9.0-rc.3/mcp/sampling-tools-protocol-version/"
---

Sampling tools and toolChoice are available from MCP 2025-11-25\. Earlier-version interaction examples cannot use those fields. Remove them or narrow the containing Tool’s protocol scope to versions that support them.

## Requirement

A sampling request uses tools and toolChoice only from MCP 2025-11-25.

## Details

**Rule ID:** `mcp.sampling.tools.protocol-version`  
**Owner:** mcp  
**Surface:** CreateMessageRequest · **Path:** `tools, toolChoice`  
**Kind:** structural  
**Requirement level:** must  
**Status:** internal · **Enforcement:** internal

## Protocol version applicability

| 2024-11-05 | 2025-03-26 | 2025-06-18 | 2025-11-25 | 2026-07-28 |
| ---------- | ---------- | ---------- | ---------- | ---------- |
| applies    | applies    | applies    | applies    | applies    |

## Required by

* **MCP Description 0.9.0, Section 9.4**  
  * 9\. Tools: [req-interaction-sampling-protocol-version](https://mcpdesc.org/docs/specification/0.9.0-rc.3/tools#req-interaction-sampling-protocol-version)

## Based on

* **Tier 1 — MCP schema.ts and normative specification text:** MCP 2025-06-18 schema.ts, CreateMessageRequest (no tools); MCP 2025-11-25 and 2026-07-28 schema.ts, CreateMessageRequestParams tools and toolChoice  
  * [validation/mcp-schemas/2025-06-18/schema.ts#L1028-L1065](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/dae694f61a31f7a3ec2af3aff709e11f70f61e48/schema/2025-06-18/schema.ts#L1028-L1065)
  * [validation/mcp-schemas/2025-11-25/schema.ts#L1573-L1622](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/dae694f61a31f7a3ec2af3aff709e11f70f61e48/schema/2025-11-25/schema.ts#L1573-L1622)
  * [validation/mcp-schemas/2026-07-28/schema.ts#L2086-L2152](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/dae694f61a31f7a3ec2af3aff709e11f70f61e48/schema/2026-07-28/schema.ts#L2086-L2152)

## Examples

### Invalid example

Source: [expected-invalid/invalid-tool-interaction-example-semantics.json](https://github.com/mcpdesc/mcpdesc-specification/blob/v0.9.0-rc.3/spec/draft/fixtures/expected-invalid/invalid-tool-interaction-example-semantics.json) · Selected: `/tools/0/interactionExamples/broken/steps/2/request`

```json
{
  "messages": [
    {
      "role": "user",
      "content": {
        "type": "text",
        "text": "Summarize the release plan."
      }
    }
  ],
  "tools": [
    {
      "name": "diff_summary",
      "inputSchema": {
        "type": "object"
      }
    }
  ],
  "maxTokens": 120
}
```

## Rule Source Code

[interaction.yaml](https://github.com/mcpdesc/mcpdesc-specification/blob/v0.9.0-rc.3/spec/draft/validation/rules/interaction.yaml) at immutable tag [v0.9.0-rc.3](https://github.com/mcpdesc/mcpdesc-specification/blob/v0.9.0-rc.3/spec/draft).