diff --git a/sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_common/_models/_completions.py b/sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_common/_models/_completions.py
new file mode 100644
index 000000000000..0fa5bca388fc
--- /dev/null
+++ b/sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_common/_models/_completions.py
@@ -0,0 +1,73 @@
+from typing import Optional, List
+from pydantic import BaseModel
+
+from azure.ai.evaluation._common._models._messages import ChatMessage
+
+class InputTokenDetails(BaseModel):
+    """
+    Represents details about input tokens.
+
+    Attributes:
+        cached_tokens (Optional[int]): The number of cached tokens.
+    """
+    cached_tokens: Optional[int] = None
+
+class OutputTokenDetails(BaseModel):
+    """
+    Represents details about output tokens.
+
+    Attributes:
+        reasoning_tokens (Optional[int]): The number of reasoning tokens.
+    """
+    reasoning_tokens: Optional[int] = None
+
+class CompletionUsage(BaseModel):
+    """
+    Represents the usage details of a completion.
+
+    Attributes:
+        output_tokens (int): The number of output tokens.
+        input_tokens (int): The number of input tokens.
+        total_tokens (int): The total number of tokens.
+        input_token_details (Optional[InputTokenDetails]): Details about input tokens.
+        output_token_details (Optional[OutputTokenDetails]): Details about output tokens.
+    """
+    output_tokens: int
+    input_tokens: int
+    total_tokens: int
+    input_token_details: Optional[InputTokenDetails] = None
+    output_token_details: Optional[OutputTokenDetails] = None
+
+class IncompleteDetails(BaseModel):
+    """
+    Represents details about incomplete completions.
+
+    Attributes:
+        reason (str): The reason for the incomplete status.
+    """
+    reason: str
+
+class Completion(BaseModel):
+    """
+    Represents a completion.
+
+    Attributes:
+        agent_id (str): The ID of the agent.
+        completion_id (str): The ID of the completion.
+        created_at (int): The timestamp when the completion was created.
+        completed_at (int): The timestamp when the completion was completed.
+        status (str): The status of the completion.
+        output (List[ChatMessage]): The output messages of the completion.
+        thread_id (str): The ID of the thread the completion belongs to.
+        usage (CompletionUsage): The usage details of the completion.
+        incomplete_details (Optional[IncompleteDetails]): Details about incomplete completions.
+    """
+    agent_id: str
+    completion_id: str
+    created_at: int
+    completed_at: int
+    status: str
+    output: List[ChatMessage] = []
+    thread_id: str
+    usage: CompletionUsage
+    incomplete_details: Optional[IncompleteDetails] = None
diff --git a/sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_common/_models/_messages.py b/sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_common/_models/_messages.py
new file mode 100644
index 000000000000..904c3bca2af8
--- /dev/null
+++ b/sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_common/_models/_messages.py
@@ -0,0 +1,199 @@
+import datetime
+import json
+from enum import Enum
+
+from pydantic import BaseModel
+
+from typing import List, Optional, Union, Dict, Any
+
+
+class AuthorRole(Enum):
+    USER = "user"
+    AGENT = "agent"
+    SYSTEM = "system"
+    TOOL = "tool"
+    DEVELOPER = "developer"
+
+class AIContent(BaseModel):
+    """
+    Base class for content of a message.
+
+    Attributes:
+        type (str): The type of the content.
+    """
+    type: str
+
+class Annotation(BaseModel):
+    """
+    Represents an annotation that links a portion of message content to a specific tool result or an external reference.
+
+    Attributes:
+        tool_call_id (Optional[str]): The ID of the tool call that produced the result being referenced by this annotation.
+                                      Optional if the annotation references an external URL instead.
+        json_path (Optional[str]): A JSONPath query into the result object of the tool call.
+                                   This path should locate the specific value within the tool result relevant to this annotation.
+                                   Optional if referencing an external URL.
+        url (Optional[str]): A URL to an external resource that provides additional context or references the annotated content.
+                             Optional if referencing a tool call result.
+        start (Optional[int]): The start index of the text span in the message content that this annotation applies to.
+        end (Optional[int]): The end index of the text span in the message content that this annotation applies to.
+    """
+    tool_call_id: Optional[str] = None
+    json_path: Optional[str] = None
+    url: Optional[str] = None
+    start: Optional[int] = None
+    end: Optional[int] = None
+
+class ContentFilterContent(AIContent):
+    """
+    Represents content filtered by a content filter.
+
+    Attributes:
+        type (str): The type of the content, which is always 'content_filter'.
+        content_filter (str): The content filter applied.
+        detected (bool): Indicates whether the content was detected by the filter.
+    """
+    type: str = "content_filter"
+    content_filter: str
+    detected: bool
+
+class RefusalContent(AIContent):
+    """
+    Represents refusal content.
+
+    Attributes:
+        type (str): The type of the content, which is always 'refusal'.
+        refusal (str): The refusal message.
+    """
+    type: str = "refusal"
+    refusal: str
+
+class TextContent(AIContent):
+    """
+    Represents text content.
+
+    Attributes:
+        type (str): The type of the content, which is always 'text'.
+        text (str): The text content.
+        annotations (List[Annotation]): A list of annotations associated with the text content.
+    """
+    type: str = "text"
+    text: str
+    annotations: List[Annotation] = []
+
+class ToolCallContent(AIContent):
+    """
+    Represents tool call content.
+
+    Attributes:
+        type (str): The type of the content, which is always 'tool_call'.
+        name (str): The name of the tool.
+        tool_call_id (str): The ID of the tool call.
+        arguments (Optional[Dict[str, Any]]): The arguments for the tool call.
+    """
+    type: str = "tool_call"
+    name: str
+    tool_call_id: str
+    arguments: Optional[Dict[str, Any]] = None
+
+class ToolResultContent(AIContent):
+    """
+    Represents tool result content.
+
+    Attributes:
+        type (str): The type of the content, which is always 'tool_result'.
+        tool_call_id (str): The ID of the tool call.
+        results (Optional[Any]): The results of the tool call.
+    """
+    type: str = "tool_result"
+    tool_call_id: str
+    results: Optional[Any] = None
+
+class FileContent(AIContent):
+    """
+    Represents file content.
+
+    Attributes:
+        type (str): The type of the content, which is always 'file'.
+        file_name (Optional[str]): The name of the file.
+        mime_type (Optional[str]): The MIME type of the file.
+        uri (Optional[str]): The URI of the file.
+        data_uri (Optional[str]): The data URI of the file.
+        data (Optional[bytes]): The binary data of the file.
+    """
+    type: str = "file"
+    file_name: Optional[str] = None
+    mime_type: Optional[str] = None
+    uri: Optional[str] = None
+    data_uri: Optional[str] = None
+    data: Optional[bytes] = None
+
+class AudioContent(FileContent):
+    """
+    Represents audio content.
+
+    Attributes:
+        type (str): The type of the content, which is always 'audio'.
+        duration (Optional[short]): The duration of the audio content.
+    """
+    type: str = "audio"
+    duration: Optional[int] = None
+
+class ImageContent(FileContent):
+    """
+    Represents image content.
+
+    Attributes:
+        type (str): The type of the content, which is always 'image'.
+        width (Optional[int]): The width of the image.
+        height (Optional[int]): The height of the image.
+    """
+    type: str = "image"
+    width: Optional[int] = None
+    height: Optional[int] = None
+
+class VideoContent(FileContent):
+    """
+    Represents video content.
+
+    Attributes:
+        type (str): The type of the content, which is always 'video'.
+        duration (Optional[int]): The duration of the video.
+        width (Optional[int]): The width of the video.
+        height (Optional[int]): The height of the video.
+    """
+    type: str = "video"
+    duration: Optional[int] = None
+    width: Optional[int] = None
+    height: Optional[int] = None
+
+class ChatMessage(BaseModel):
+    """
+    Represents a chat message.
+
+    Attributes:
+        user_id (Optional[str]): The ID of the user who sent the message.
+        agent_id (Optional[str]): The ID of the agent who sent the message.
+        message_id (str): The ID of the message.
+        completion_id (Optional[str]): The ID of the completion associated with the message.
+        thread_id (str): The ID of the thread the message belongs to.
+        role (AuthorRole): The role of the message sender.
+        content (List[AIContent]): The content of the message.
+        author_name (Optional[str]): The name of the author of the message.
+        created_at (Optional[int]): The timestamp when the message was created.
+        completed_at (Optional[int]): The timestamp when the message was completed.
+    """
+    user_id: Optional[str] = None
+    agent_id: Optional[str] = None
+    message_id: str
+    completion_id: Optional[str] = None
+    thread_id: str
+    role: AuthorRole
+    content: List[AIContent]
+    author_name: Optional[str] = None
+    created_at: Optional[int] = None
+    completed_at: Optional[int] = None
+
+
+
+
diff --git a/sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_common/_models/_threads.py b/sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_common/_models/_threads.py
new file mode 100644
index 000000000000..ea1cb26409fc
--- /dev/null
+++ b/sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_common/_models/_threads.py
@@ -0,0 +1,16 @@
+from typing import List
+from pydantic import BaseModel
+
+from azure.ai.evaluation._common._models._messages import ChatMessage
+
+
+class ActivityThread(BaseModel):
+    """
+    Represents an activity thread.
+
+    Attributes:
+        thread_id (str): The ID of the thread.
+        messages (List[ChatMessage]): The list of chat messages in the thread.
+    """
+    thread_id: str
+    messages: List[ChatMessage] = []
\ No newline at end of file
diff --git a/sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_common/_models/_tools.py b/sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_common/_models/_tools.py
new file mode 100644
index 000000000000..a0aa988ca9b1
--- /dev/null
+++ b/sdk/evaluation/azure-ai-evaluation/azure/ai/evaluation/_common/_models/_tools.py
@@ -0,0 +1,109 @@
+from typing import Optional, List
+from pydantic import BaseModel
+import json
+
+class ToolOverrides(BaseModel):
+    """
+    Optional overrides for tool metadata.
+
+    Attributes:
+        name (Optional[str]): The name of the tool.
+        description (Optional[str]): The description of the tool.
+        parameters (Optional[dict]): The parameters for the tool.
+    """
+    name: Optional[str] = None
+    description: Optional[str] = None
+    parameters: Optional[dict] = None
+
+class AgentToolDefinition(BaseModel):
+    """
+    Represents an agent tool definition.
+
+    Attributes:
+        type (str): The type of the tool.
+        override (Optional[ToolOverrides]): Optional overrides for tool metadata.
+    """
+    type: str
+    override: Optional[ToolOverrides] = None
+
+class FunctionToolDefinition(AgentToolDefinition):
+    """
+    Represents a function tool definition.
+
+    Attributes:
+        type (str): The type of the tool, which is always 'function'.
+        name (str): The name of the function.
+        description (Optional[str]): The description of the function.
+        parameters (Optional[dict]): JSON Schema describing the parameters, stored as raw JSON.
+        strict (Optional[bool]): Indicates if the function is strict.
+    """
+    type: str = "function"
+    name: str
+    description: Optional[str] = None
+    parameters: Optional[dict] = None
+    strict: Optional[bool] = None
+
+class BingGroundingToolDefinition(AgentToolDefinition):
+    """
+    Represents a Bing Grounding tool definition.
+
+    Attributes:
+        type (str): The type of the tool, which is always 'Microsoft.BingGrounding'.
+        connection_name (str): The name of the connection.
+    """
+    type: str = "Microsoft.BingGrounding"
+    connection_name: str
+
+class CodeInterpreterToolDefinition(AgentToolDefinition):
+    """
+    Represents a Code Interpreter tool definition.
+
+    Attributes:
+        type (str): The type of the tool, which is always 'OpenAI.CodeInterpreter'.
+        file_ids (Optional[List[str]]): A list of file IDs.
+    """
+    type: str = "OpenAI.CodeInterpreter"
+    file_ids: Optional[List[str]] = None
+
+class RankingOptions(BaseModel):
+    """
+    Represents ranking options.
+
+    Attributes:
+        score_threshold (float): The score threshold for ranking.
+        ranker (Optional[str]): The ranker used for ranking.
+    """
+    score_threshold: float
+    ranker: Optional[str] = None
+
+class FileSearchToolDefinition(AgentToolDefinition):
+    """
+    Represents a File Search tool definition.
+
+    Attributes:
+        type (str): The type of the tool, which is always 'OpenAI.FileSearch'.
+        max_num_results (Optional[int]): The maximum number of results.
+        ranking_options (Optional[RankingOptions]): The ranking options.
+        vector_store_id (Optional[str]): The ID of the vector store.
+    """
+    type: str = "OpenAI.FileSearch"
+    max_num_results: Optional[int] = None
+    ranking_options: Optional[RankingOptions] = None
+    vector_store_id: Optional[str] = None
+
+# class OpenApiToolDefinition(AgentToolDefinition):
+#     """
+#     Represents an OpenAPI tool definition.
+#
+#     Attributes:
+#         type (str): The type of the tool, which is always 'OpenApi'.
+#         name (str): The name of the tool.
+#         description (Optional[str]): The description of the tool.
+#         spec (BinaryData): The OpenAPI specification.
+#         auth (OpenApiAuthDetails): The authentication details.
+#     """
+#     type: str = "OpenApi"
+#     name: str
+#     description: Optional[str] = None
+#     spec: BinaryData
+#     auth: OpenApiAuthDetails
\ No newline at end of file