Update classes to inherit from FastMCPBaseModel instead of BaseModel

src/fastmcp/prompts/prompt.py

@@ -68,7 +68,6 @@ def __init__(
         self,
         content: Any,
         role: Literal["user", "assistant"] = "user",
-        **kwargs: Any,
     ):
         """Create Message with automatic serialization.
 
@@ -88,7 +87,7 @@ def __init__(
             serialized = pydantic_core.to_json(content, fallback=str).decode()
             normalized_content = TextContent(type="text", text=serialized)
 
-        super().__init__(role=role, content=normalized_content, **kwargs)
+        super().__init__(role=role, content=normalized_content)
 
     def to_mcp_prompt_message(self) -> PromptMessage:
         """Convert to MCP PromptMessage."""
@@ -148,7 +147,6 @@ def __init__(
         messages: str | list[Message],
         description: str | None = None,
         meta: dict[str, Any] | None = None,
-        **kwargs: Any,
     ):
         """Create PromptResult.
 
@@ -158,9 +156,7 @@ def __init__(
             meta: Optional metadata about the prompt result.
         """
         normalized = self._normalize_messages(messages)
-        super().__init__(
-            messages=normalized, description=description, meta=meta, **kwargs
-        )
+        super().__init__(messages=normalized, description=description, meta=meta)
 
     @staticmethod
     def _normalize_messages(

src/fastmcp/resources/resource.py

@@ -29,9 +29,7 @@
 from fastmcp.server.dependencies import without_injected_parameters
 from fastmcp.server.tasks.config import TaskConfig
 from fastmcp.utilities.components import FastMCPComponent
-from fastmcp.utilities.types import (
-    get_fn_name,
-)
+from fastmcp.utilities.types import get_fn_name
 
 
 class ResourceContent(pydantic.BaseModel):
@@ -65,7 +63,6 @@ def __init__(
         content: Any,
         mime_type: str | None = None,
         meta: dict[str, Any] | None = None,
-        **kwargs: Any,
     ):
         """Create ResourceContent with automatic serialization.
 
@@ -88,9 +85,7 @@ def __init__(
             normalized_content = pydantic_core.to_json(content, fallback=str).decode()
             mime_type = mime_type or "application/json"
 
-        super().__init__(
-            content=normalized_content, mime_type=mime_type, meta=meta, **kwargs
-        )
+        super().__init__(content=normalized_content, mime_type=mime_type, meta=meta)
 
     def to_mcp_resource_contents(
         self, uri: AnyUrl | str
@@ -162,7 +157,6 @@ def __init__(
         self,
         contents: str | bytes | list[ResourceContent],
         meta: dict[str, Any] | None = None,
-        **kwargs: Any,
     ):
         """Create ResourceResult.
 
@@ -171,7 +165,7 @@ def __init__(
             meta: Optional metadata about the resource result.
         """
         normalized = self._normalize_contents(contents)
-        super().__init__(contents=normalized, meta=meta, **kwargs)
+        super().__init__(contents=normalized, meta=meta)
 
     @staticmethod
     def _normalize_contents(

src/fastmcp/server/event_store.py

@@ -16,22 +16,22 @@
 from mcp.server.streamable_http import EventCallback, EventId, EventMessage, StreamId
 from mcp.server.streamable_http import EventStore as SDKEventStore
 from mcp.types import JSONRPCMessage
-from pydantic import BaseModel
 
 from fastmcp.utilities.logging import get_logger
+from fastmcp.utilities.types import FastMCPBaseModel
 
 logger = get_logger(__name__)
 
 
-class EventEntry(BaseModel):
+class EventEntry(FastMCPBaseModel):
     """Stored event entry."""
 
     event_id: str
     stream_id: str
     message: dict | None  # JSONRPCMessage serialized to dict
 
 
-class StreamEventList(BaseModel):
+class StreamEventList(FastMCPBaseModel):
     """List of event IDs for a stream."""
 
     event_ids: list[str]

src/fastmcp/server/middleware/caching.py

@@ -14,14 +14,15 @@
 from key_value.aio.wrappers.statistics.wrapper import (
     KVStoreCollectionStatistics,
 )
-from pydantic import BaseModel, Field
+from pydantic import Field
 from typing_extensions import NotRequired, Self, override
 
 from fastmcp.prompts.prompt import Message, Prompt, PromptResult
 from fastmcp.resources.resource import Resource, ResourceContent, ResourceResult
 from fastmcp.server.middleware.middleware import CallNext, Middleware, MiddlewareContext
 from fastmcp.tools.tool import Tool, ToolResult
 from fastmcp.utilities.logging import get_logger
+from fastmcp.utilities.types import FastMCPBaseModel
 
 logger: Logger = get_logger(name=__name__)
 
@@ -34,15 +35,15 @@
 GLOBAL_KEY = "__global__"
 
 
-class CachableResourceContent(BaseModel):
+class CachableResourceContent(FastMCPBaseModel):
     """A wrapper for ResourceContent that can be cached."""
 
     content: str | bytes
     mime_type: str | None = None
     meta: dict[str, Any] | None = None
 
 
-class CachableResourceResult(BaseModel):
+class CachableResourceResult(FastMCPBaseModel):
     """A wrapper for ResourceResult that can be cached."""
 
     contents: list[CachableResourceContent]
@@ -75,7 +76,7 @@ def unwrap(self) -> ResourceResult:
         )
 
 
-class CachableToolResult(BaseModel):
+class CachableToolResult(FastMCPBaseModel):
     content: list[mcp.types.ContentBlock]
     structured_content: dict[str, Any] | None
     meta: dict[str, Any] | None
@@ -96,14 +97,14 @@ def unwrap(self) -> ToolResult:
         )
 
 
-class CachableMessage(BaseModel):
+class CachableMessage(FastMCPBaseModel):
     """A wrapper for Message that can be cached."""
 
     role: str
     content: mcp.types.TextContent | mcp.types.EmbeddedResource
 
 
-class CachablePromptResult(BaseModel):
+class CachablePromptResult(FastMCPBaseModel):
     """A wrapper for PromptResult that can be cached."""
 
     messages: list[CachableMessage]
@@ -168,7 +169,7 @@ class GetPromptSettings(SharedMethodSettings):
     """Configuration options for Prompt-related caching."""
 
 
-class ResponseCachingStatistics(BaseModel):
+class ResponseCachingStatistics(FastMCPBaseModel):
     list_tools: KVStoreCollectionStatistics | None = Field(default=None)
     list_resources: KVStoreCollectionStatistics | None = Field(default=None)
     list_prompts: KVStoreCollectionStatistics | None = Field(default=None)

src/fastmcp/server/sampling/sampling_tool.py

@@ -7,12 +7,13 @@
 from typing import Any
 
 from mcp.types import Tool as SDKTool
-from pydantic import BaseModel, ConfigDict
+from pydantic import ConfigDict
 
 from fastmcp.tools.tool import ParsedFunction
+from fastmcp.utilities.types import FastMCPBaseModel
 
 
-class SamplingTool(BaseModel):
+class SamplingTool(FastMCPBaseModel):
     """A tool that can be used during LLM sampling.
 
     SamplingTools bundle a tool's schema (name, description, parameters) with

src/fastmcp/tools/tool.py

@@ -117,9 +117,7 @@ def __init__(
                 )
 
         super().__init__(
-            content=converted_content,
-            structured_content=structured_content,
-            meta=meta,
+            content=converted_content, structured_content=structured_content, meta=meta
         )
 
     def to_mcp_result(