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Sampling changedspecification/draft/client/sampling

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11# Sampling

3<div id="enable-section-numbers" />

3> [!WARNING]

5> **Deprecated**: The Sampling feature is deprecated as of protocol version

6> `2026-07-28`

7> ([SEP-2577](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2577)).

8> Under the [feature lifecycle policy](/community/feature-lifecycle), it remains

9> in the specification for at least twelve months after this revision's release

10> before it becomes eligible for removal. New implementations **SHOULD NOT**

11> adopt it; existing implementations **SHOULD** migrate to integrating directly

12> with LLM provider APIs. See the [deprecated features

13> registry](/specification/draft/deprecated).

414

5<Warning>

6 **Deprecated**: The Sampling feature is deprecated as of protocol version

7 `2026-07-28`

8 ([SEP-2577](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2577)).

9 Under the [feature lifecycle policy](/community/feature-lifecycle), it remains

10 in the specification for at least twelve months after this revision's release

11 before it becomes eligible for removal. New implementations **SHOULD NOT**

12 adopt it; existing implementations **SHOULD** migrate to integrating directly

13 with LLM provider APIs. See the [deprecated features

14 registry](/specification/draft/deprecated).

15</Warning>

1715The Model Context Protocol (MCP) provides a standardized way for servers to request LLM

1816sampling ("completions" or "generations") from language models via clients. This flow

1917allows clients to maintain control over model access, selection, and permissions while

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3028their needs—the protocol itself does not mandate any specific user interaction

3129model.

3230

33<Warning>

34 For trust & safety and security, there **SHOULD** always

35 be a human in the loop with the ability to deny sampling requests.

31> [!WARNING]

32>

33> For trust & safety and security, there **SHOULD** always

34> be a human in the loop with the ability to deny sampling requests.

35>

36> Applications **SHOULD**:

37>

38> * Provide UI that makes it easy and intuitive to review sampling requests

39> * Allow users to view and edit prompts before sending

40> * Present generated responses for review before delivery

3641

37 Applications **SHOULD**:

39 * Provide UI that makes it easy and intuitive to review sampling requests

40 * Allow users to view and edit prompts before sending

41 * Present generated responses for review before delivery

42</Warning>

4442## Tools in Sampling

4543

4644Servers can request that the client's LLM use tools during sampling by providing a `tools` array and optional `toolChoice` configuration in their sampling requests. The tool definitions in the `tools` array are scoped to the sampling request — they don't need to correspond to registered tools. This enables servers to implement agentic behaviors where the LLM can call specially designated tools, receive results, and continue the conversation - all within a single sampling request flow.

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9290}

9391```

9492

95<Note>

96 The `includeContext` parameter values `"thisServer"` and `"allServers"` are

97 deprecated under the [feature lifecycle

98 policy](/community/feature-lifecycle#deprecating-a-feature)

99 ([SEP-2596](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2596));

100 they will be removed no later than the Sampling feature itself. Servers

101 **SHOULD** avoid using these values (e.g. can just omit `includeContext` since

102 it defaults to `"none"`), and **SHOULD NOT** use them unless the client

103 declares `sampling.context` capability. See the [deprecated features

104 registry](/specification/draft/deprecated).

105</Note>

93> [!NOTE]

94>

95> The `includeContext` parameter values `"thisServer"` and `"allServers"` are

96> deprecated under the [feature lifecycle

97> policy](/community/feature-lifecycle#deprecating-a-feature)

98> ([SEP-2596](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2596));

99> they will be removed no later than the Sampling feature itself. Servers

100> **SHOULD** avoid using these values (e.g. can just omit `includeContext` since

101> it defaults to `"none"`), and **SHOULD NOT** use them unless the client

102> declares `sampling.context` capability. See the [deprecated features

103> registry](/specification/draft/deprecated).

106104

107105## Protocol Messages

108106