Move OpenAI sampling handler out of experimental

- Move from fastmcp.experimental.sampling.handlers.openai to fastmcp.server.sampling.openai
- Update docs and tests to use new import path
- Remove experimental handlers directory

docs/servers/sampling.mdx

@@ -463,7 +463,7 @@ FastMCP provides an OpenAI-compatible sampling handler that supports both basic
 import os
 from openai import OpenAI
 from fastmcp import FastMCP
-from fastmcp.experimental.sampling.handlers.openai import OpenAISamplingHandler
+from fastmcp.server.sampling.openai import OpenAISamplingHandler
 
 server = FastMCP(
     name="Sampling Server",
@@ -487,7 +487,7 @@ import os
 from openai import OpenAI
 
 from fastmcp import FastMCP, Context
-from fastmcp.experimental.sampling.handlers.openai import OpenAISamplingHandler
+from fastmcp.server.sampling.openai import OpenAISamplingHandler
 
 
 async def async_main():
@@ -545,7 +545,7 @@ The fallback handler fully supports sampling with tools:
 
 ```python
 from fastmcp import FastMCP, Context
-from fastmcp.experimental.sampling.handlers.openai import OpenAISamplingHandler
+from fastmcp.server.sampling.openai import OpenAISamplingHandler
 from openai import OpenAI
 import os
 

src/fastmcp/experimental/sampling/handlers/base.py

@@ -1,21 +0,0 @@
-from abc import ABC, abstractmethod
-from collections.abc import Awaitable
-
-from mcp import ClientSession, CreateMessageResult
-from mcp.server.session import ServerSession
-from mcp.shared.context import LifespanContextT, RequestContext
-from mcp.types import CreateMessageRequestParams as SamplingParams
-from mcp.types import (
-    SamplingMessage,
-)
-
-
-class BaseLLMSamplingHandler(ABC):
-    @abstractmethod
-    def __call__(
-        self,
-        messages: list[SamplingMessage],
-        params: SamplingParams,
-        context: RequestContext[ServerSession, LifespanContextT]
-        | RequestContext[ClientSession, LifespanContextT],
-    ) -> str | CreateMessageResult | Awaitable[str | CreateMessageResult]: ...

src/fastmcp/server/sampling/openai.py

@@ -1,5 +1,7 @@
+"""OpenAI sampling handler for FastMCP servers."""
+
 import json
-from collections.abc import Iterator, Sequence
+from collections.abc import Awaitable, Callable, Iterator, Sequence
 from typing import Any, get_args
 
 from mcp import ClientSession, ServerSession
@@ -35,20 +37,30 @@ try:
     from openai.types.shared_params import FunctionDefinition
 except ImportError as e:
     raise ImportError(
-        "The `openai` package is not installed. Please install `fastmcp[openai]` or add `openai` to your dependencies manually."
+        "The `openai` package is not installed. "
+        "Please install `fastmcp[openai]` or add `openai` to your dependencies manually."
     ) from e
 
-from typing_extensions import override
 
-from fastmcp.experimental.sampling.handlers.base import BaseLLMSamplingHandler
+SamplingHandlerResult = str | CreateMessageResult | CreateMessageResultWithTools
+
+ServerSamplingHandler = Callable[
+    [
+        list[SamplingMessage],
+        SamplingParams,
+        RequestContext[ServerSession, LifespanContextT],
+    ],
+    SamplingHandlerResult | Awaitable[SamplingHandlerResult],
+]
 
 
-class OpenAISamplingHandler(BaseLLMSamplingHandler):
+class OpenAISamplingHandler:
+    """Sampling handler that uses the OpenAI API."""
+
     def __init__(self, default_model: ChatModel, client: OpenAI | None = None):
         self.client: OpenAI = client or OpenAI()
         self.default_model: ChatModel = default_model
 
-    @override
     async def __call__(
         self,
         messages: list[SamplingMessage],

tests/server/sampling/test_openai_handler.py

@@ -18,7 +18,7 @@ from openai.types.chat import (
 )
 from openai.types.chat.chat_completion import Choice
 
-from fastmcp.experimental.sampling.handlers.openai import OpenAISamplingHandler
+from fastmcp.server.sampling.openai import OpenAISamplingHandler
 
 
 def test_convert_sampling_messages_to_openai_messages():

uv.lock

@@ -765,8 +765,7 @@ provides-extras = ["anthropic", "openai"]
 dev = [
     { name = "dirty-equals", specifier = ">=0.9.0" },
     { name = "fastapi", specifier = ">=0.115.12" },
-    { name = "fastmcp", extras = ["anthropic"] },
-    { name = "fastmcp", extras = ["openai"] },
+    { name = "fastmcp", extras = ["anthropic", "openai"] },
     { name = "inline-snapshot", extras = ["dirty-equals"], specifier = ">=0.27.2" },
     { name = "ipython", specifier = ">=8.12.3" },
     { name = "pdbpp", specifier = ">=0.11.7" },