diff --git a/pyproject.toml b/pyproject.toml
index 75a7d6b5..78cf1fa8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -93,7 +93,7 @@ target-version = "py311"
 [tool.ruff.lint]
 # https://docs.astral.sh/ruff/rules/
 # https://docs.astral.sh/ruff/formatter/#conflicting-lint-rules
-select = ["A", "B0", "C4", "D2", "D4", "E", "F", "I"]
+select = ["A", "B0", "C4", "D2", "D4", "E", "F", "FURB", "I", "PYI", "UP"]
 ignore = ["D203", "D206", "D213", "D400", "D401", "D413", "D415", "E1", "E501"]
 
 [tool.eva]
diff --git a/scripts/run_text_only.py b/scripts/run_text_only.py
index 7d17163b..1362e37b 100644
--- a/scripts/run_text_only.py
+++ b/scripts/run_text_only.py
@@ -25,7 +25,7 @@
 import os
 import shutil
 import sys
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 from pathlib import Path
 from typing import Any
 
@@ -514,7 +514,7 @@ async def run_record(
     user_message = record.user_goal["starting_utterance"]
     end_reason = "max_turns"
     turn_count = 0
-    started_at = datetime.now(timezone.utc)
+    started_at = datetime.now(UTC)
 
     for turn in range(max_turns):
         turn_count = turn + 1
@@ -546,7 +546,7 @@ async def run_record(
     else:
         end_reason = "max_turns"
 
-    ended_at = datetime.now(timezone.utc)
+    ended_at = datetime.now(UTC)
     duration = (ended_at - started_at).total_seconds()
     logger.info(f"Conversation ended: {end_reason} ({turn_count} turns, {duration:.1f}s)")
 
diff --git a/src/eva/assistant/agentic/audio_llm_system.py b/src/eva/assistant/agentic/audio_llm_system.py
index 6a5cdd77..369e0510 100644
--- a/src/eva/assistant/agentic/audio_llm_system.py
+++ b/src/eva/assistant/agentic/audio_llm_system.py
@@ -5,8 +5,9 @@
 audio so the model has full conversational context across turns.
 """
 
+from collections.abc import AsyncGenerator
 from pathlib import Path
-from typing import Any, AsyncGenerator, Optional
+from typing import Any
 
 from eva.assistant.agentic.audit_log import AuditLog
 from eva.assistant.agentic.system import AgenticSystem
@@ -37,7 +38,7 @@ def __init__(
         tool_handler: ToolExecutor,
         audit_log: AuditLog,
         alm_client: ALMvLLMClient,
-        output_dir: Optional[Path] = None,
+        output_dir: Path | None = None,
     ):
         super().__init__(
             current_date_time=current_date_time,
diff --git a/src/eva/assistant/agentic/audit_log.py b/src/eva/assistant/agentic/audit_log.py
index 7fc28438..cc238c0a 100644
--- a/src/eva/assistant/agentic/audit_log.py
+++ b/src/eva/assistant/agentic/audit_log.py
@@ -4,7 +4,7 @@
 import time
 from enum import StrEnum
 from pathlib import Path
-from typing import Any, Optional
+from typing import Any
 
 from pydantic import BaseModel
 
@@ -32,11 +32,11 @@ class ConversationMessage(BaseModel):
 
     role: MessageRole
     content: str
-    tool_calls: Optional[list[dict[str, Any]]] = None
-    tool_call_id: Optional[str] = None
-    name: Optional[str] = None  # For tool messages
-    turn_id: Optional[int] = None  # For associating transcription updates
-    reasoning: Optional[str] = None  # For model reasoning (e.g., from OpenAI o1)
+    tool_calls: list[dict[str, Any]] | None = None
+    tool_call_id: str | None = None
+    name: str | None = None  # For tool messages
+    turn_id: int | None = None  # For associating transcription updates
+    reasoning: str | None = None  # For model reasoning (e.g., from OpenAI o1)
 
     def to_dict(self) -> dict[str, Any]:
         """Convert to a plain dict, excluding None fields and internal tracking fields."""
@@ -47,17 +47,17 @@ class LLMCall(BaseModel):
     """Record of an LLM call."""
 
     messages: list[dict]
-    tools: Optional[list[dict]] = None
-    response: Optional[ConversationMessage] = None
+    tools: list[dict] | None = None
+    response: ConversationMessage | None = None
     duration_seconds: float = 0.0
     start_time: str = ""
     end_time: str = ""
     status: str = "success"
-    model: Optional[str] = None
+    model: str | None = None
     # New fields for enhanced tracking (optional for backward compatibility)
-    latency_ms: Optional[float] = None
-    error_type: Optional[str] = None
-    error_source: Optional[str] = None
+    latency_ms: float | None = None
+    error_type: str | None = None
+    error_source: str | None = None
     retry_attempt: int = 0
 
 
@@ -75,13 +75,13 @@ def __init__(self):
         self.conversation_messages: list[ConversationMessage] = []  # Full message sequence for LLM context
         self._tool_calls_count = 0
         self._tools_called: list[str] = []
-        self._last_tool_call: Optional[str] = None  # Track last tool called for matching responses
+        self._last_tool_call: str | None = None  # Track last tool called for matching responses
 
     def append_user_input(
         self,
         content: str,
-        timestamp_ms: Optional[str] = None,
-        turn_id: Optional[int] = None,
+        timestamp_ms: str | None = None,
+        turn_id: int | None = None,
     ) -> None:
         """Record user input.
 
@@ -189,7 +189,7 @@ def append_assistant_output(
         self,
         content: str,
         tool_calls: list[dict[str, Any]] | None = None,
-        timestamp_ms: Optional[str] = None,
+        timestamp_ms: str | None = None,
     ) -> None:
         """Record assistant output.
 
@@ -236,7 +236,7 @@ def append_tool_message(self, tool_call_id: str, content: str) -> None:
         )
         logger.debug(f"Audit: tool message for call_id {tool_call_id}")
 
-    def append_llm_call(self, llm_call: LLMCall, agent_name: Optional[str] = None) -> None:
+    def append_llm_call(self, llm_call: LLMCall, agent_name: str | None = None) -> None:
         """Record an LLM call."""
         response_content = llm_call.response.content if llm_call.response else ""
         response_dict = llm_call.response.to_dict() if llm_call.response else None
@@ -276,7 +276,7 @@ def append_tool_call(
         self,
         tool_name: str,
         parameters: dict[str, Any],
-        response: Optional[dict[str, Any]] = None,
+        response: dict[str, Any] | None = None,
     ) -> None:
         """Record a tool call and its response."""
         # Record tool call in transcript
@@ -342,7 +342,7 @@ def append_realtime_tool_call(
 
     def get_conversation_messages(
         self,
-        max_messages: Optional[int] = None,
+        max_messages: int | None = None,
     ) -> list[ConversationMessage]:
         """Get conversation messages for LLM context.
 
diff --git a/src/eva/assistant/agentic/system.py b/src/eva/assistant/agentic/system.py
index f9df217c..a4125725 100644
--- a/src/eva/assistant/agentic/system.py
+++ b/src/eva/assistant/agentic/system.py
@@ -5,8 +5,9 @@
 import json
 import time
 import warnings
+from collections.abc import AsyncGenerator
 from pathlib import Path
-from typing import Any, AsyncGenerator
+from typing import Any
 
 from eva.assistant.agentic.audit_log import (
     AuditLog,
@@ -220,7 +221,7 @@ async def _run_tool_loop(
                 llm_call_response = ConversationMessage(
                     role=MessageRole.ASSISTANT,
                     content=response_content,
-                    tool_calls=tool_calls_dicts if tool_calls_dicts else None,
+                    tool_calls=tool_calls_dicts or None,
                     reasoning=llm_stats.get("reasoning"),
                 )
 
diff --git a/src/eva/assistant/pipeline/alm_vllm.py b/src/eva/assistant/pipeline/alm_vllm.py
index 657ca4c3..ae41f289 100644
--- a/src/eva/assistant/pipeline/alm_vllm.py
+++ b/src/eva/assistant/pipeline/alm_vllm.py
@@ -10,7 +10,7 @@
 import struct
 import time
 import wave
-from typing import Any, Optional
+from typing import Any
 
 from openai import AsyncOpenAI
 
@@ -163,7 +163,7 @@ def build_audio_user_message(
     async def complete(
         self,
         messages: list[dict[str, Any]],
-        tools: Optional[list[dict]] = None,
+        tools: list[dict] | None = None,
     ) -> tuple[Any, dict[str, Any]]:
         """Chat completion with audio and tool support.
 
@@ -188,7 +188,7 @@ async def complete(
             kwargs["tools"] = tools
             kwargs["tool_choice"] = "auto"
 
-        last_exception: Optional[Exception] = None
+        last_exception: Exception | None = None
         for attempt in range(self.max_retries + 1):
             try:
                 start_time = time.time()
diff --git a/src/eva/assistant/pipeline/audio_llm_processor.py b/src/eva/assistant/pipeline/audio_llm_processor.py
index bb5b24b3..25d16a7a 100644
--- a/src/eva/assistant/pipeline/audio_llm_processor.py
+++ b/src/eva/assistant/pipeline/audio_llm_processor.py
@@ -23,7 +23,7 @@
 import wave
 from collections.abc import Awaitable
 from pathlib import Path
-from typing import Any, Optional
+from typing import Any
 
 from openai import AsyncOpenAI
 from pipecat.frames.frames import (
@@ -81,7 +81,7 @@ def __init__(
         self,
         context,
         user_context_aggregator,
-        pre_speech_secs: Optional[float] = None,
+        pre_speech_secs: float | None = None,
         **kwargs,
     ):
         super().__init__(**kwargs)
@@ -176,7 +176,7 @@ def __init__(
         audit_log: AuditLog,
         alm_client: ALMvLLMClient,
         audio_collector: AudioLLMUserAudioCollector,
-        output_dir: Optional[Path] = None,
+        output_dir: Path | None = None,
         **kwargs,
     ) -> None:
         super().__init__(**kwargs)
@@ -195,11 +195,11 @@ def __init__(
         )
 
         # State tracking (mirrors BenchmarkAgentProcessor)
-        self._current_query_task: Optional[asyncio.Task] = None
+        self._current_query_task: asyncio.Task | None = None
         self._interrupted = asyncio.Event()
 
         # Optional callback for transcript saving (set by server.py)
-        self.on_assistant_response: Optional[Awaitable] = None
+        self.on_assistant_response: Awaitable | None = None
 
     async def process_frame(self, frame: Frame, direction: FrameDirection) -> None:
         if isinstance(frame, (EndFrame, CancelFrame)):
@@ -410,7 +410,7 @@ def __init__(
         audio_collector: AudioLLMUserAudioCollector,
         model: str = "",
         params: dict[str, Any] = None,
-        system_prompt: Optional[str] = None,
+        system_prompt: str | None = None,
         sample_rate: int = PIPELINE_SAMPLE_RATE,
         **kwargs,
     ):
@@ -426,7 +426,7 @@ def __init__(
         self._client: AsyncOpenAI = AsyncOpenAI(api_key=self._api_key, base_url=base_url)
 
         # Callback for when transcription is ready (set by server.py)
-        self.on_transcription: Optional[Any] = None
+        self.on_transcription: Any | None = None
 
         # Track background transcription tasks so they can complete even during interruptions
         self._transcription_tasks: list[asyncio.Task] = []
@@ -463,7 +463,7 @@ async def process_frame(self, frame: Frame, direction: FrameDirection) -> None:
         # Clean up completed tasks
         self._transcription_tasks = [t for t in self._transcription_tasks if not t.done()]
 
-    async def transcribe(self, timestamp: str, turn_id: Optional[int] = None) -> Optional[str]:
+    async def transcribe(self, timestamp: str, turn_id: int | None = None) -> str | None:
         """Transcribe audio from the collector using chat completions.
 
         This method can be called directly from event handlers or via frame processing.
@@ -479,9 +479,7 @@ async def transcribe(self, timestamp: str, turn_id: Optional[int] = None) -> Opt
         audio_data = self._audio_collector.peek_buffered_audio()
         return await self._transcribe_audio(audio_data, timestamp, turn_id)
 
-    async def _transcribe_audio(
-        self, audio_data: bytes, timestamp: str, turn_id: Optional[int] = None
-    ) -> Optional[str]:
+    async def _transcribe_audio(self, audio_data: bytes, timestamp: str, turn_id: int | None = None) -> str | None:
         """Transcribe pre-captured audio data using chat completions.
 
         This method takes audio data directly instead of reading from the collector,
diff --git a/src/eva/assistant/pipeline/nvidia_stt.py b/src/eva/assistant/pipeline/nvidia_stt.py
index 620004a1..1e6b0974 100644
--- a/src/eva/assistant/pipeline/nvidia_stt.py
+++ b/src/eva/assistant/pipeline/nvidia_stt.py
@@ -10,7 +10,7 @@
 import json
 import ssl
 import time
-from typing import AsyncGenerator, Optional
+from collections.abc import AsyncGenerator
 
 import websockets
 from loguru import logger
@@ -48,7 +48,7 @@ def __init__(
         self,
         *,
         url: str = "ws://localhost:8080",
-        api_key: Optional[str] = None,
+        api_key: str | None = None,
         sample_rate: int = 16000,
         verify: bool = True,
         **kwargs,
@@ -58,7 +58,7 @@ def __init__(
         self._api_key = api_key
         self._verify = verify
         self._websocket = None
-        self._receive_task: Optional[asyncio.Task] = None
+        self._receive_task: asyncio.Task | None = None
         self._ready = False
 
     def can_generate_metrics(self) -> bool:
@@ -135,7 +135,7 @@ async def _connect_websocket(self):
             self._websocket = await websockets.connect(
                 self._url,
                 ssl=ssl_context,
-                additional_headers=extra_headers if extra_headers else None,
+                additional_headers=extra_headers or None,
             )
             self._ready = False
 
@@ -149,7 +149,7 @@ async def _connect_websocket(self):
                 else:
                     logger.warning(f"{self} unexpected initial message: {data}")
                     self._ready = True
-            except asyncio.TimeoutError:
+            except TimeoutError:
                 logger.warning(f"{self} timeout waiting for ready, proceeding")
                 self._ready = True
 
diff --git a/src/eva/assistant/pipeline/realtime_llm.py b/src/eva/assistant/pipeline/realtime_llm.py
index b502b4df..9d93c035 100644
--- a/src/eva/assistant/pipeline/realtime_llm.py
+++ b/src/eva/assistant/pipeline/realtime_llm.py
@@ -14,7 +14,7 @@
 import struct
 import time
 from dataclasses import dataclass
-from typing import Any, Optional
+from typing import Any
 
 from pipecat.frames.frames import Frame, InputAudioRawFrame, VADUserStartedSpeakingFrame, VADUserStoppedSpeakingFrame
 from pipecat.processors.frame_processor import FrameDirection
@@ -75,14 +75,14 @@ def __init__(self, *, audit_log: AuditLog, **kwargs: Any) -> None:
 
         # Assistant response accumulation (across audio_transcript_delta events)
         self._current_assistant_transcript_parts: list[str] = []
-        self._assistant_response_start_wall_ms: Optional[str] = None
+        self._assistant_response_start_wall_ms: str | None = None
 
         # Track whether we're mid-assistant-response (for interruption flushing)
         self._assistant_responding: bool = False
 
         # Track audio frame timing for VAD delay calculation
-        self._last_audio_frame_time: Optional[float] = None
-        self._vad_delay_ms: Optional[int] = None
+        self._last_audio_frame_time: float | None = None
+        self._vad_delay_ms: int | None = None
 
     async def process_frame(self, frame: Frame, direction: FrameDirection) -> None:
         """Track audio frame timing before passing to parent.
@@ -295,7 +295,7 @@ def _reset_assistant_state(self) -> None:
         self._assistant_responding = False
 
     @property
-    def last_vad_delay_ms(self) -> Optional[int]:
+    def last_vad_delay_ms(self) -> int | None:
         """Return the most recent VAD delay in milliseconds.
 
         This is the time between when audio frames stopped arriving and when
diff --git a/src/eva/assistant/pipeline/services.py b/src/eva/assistant/pipeline/services.py
index c8ee3eff..30ddc667 100644
--- a/src/eva/assistant/pipeline/services.py
+++ b/src/eva/assistant/pipeline/services.py
@@ -4,7 +4,8 @@
 """
 
 import datetime
-from typing import Any, AsyncGenerator, Optional
+from collections.abc import AsyncGenerator
+from typing import Any
 
 from deepgram import LiveOptions
 from openai import AsyncAzureOpenAI, BadRequestError
@@ -82,8 +83,8 @@
 
 
 def create_stt_service(
-    model: Optional[str],
-    params: Optional[dict[str, Any]] = None,
+    model: str | None,
+    params: dict[str, Any] | None = None,
     language_code: str = "en",
 ) -> STTService | None:
     """Create speech-to-text service.
@@ -212,8 +213,8 @@ def create_stt_service(
 
 
 def create_tts_service(
-    model: Optional[str],
-    params: Optional[dict[str, Any]] = None,
+    model: str | None,
+    params: dict[str, Any] | None = None,
     language_code: str = "en",
 ) -> TTSService | None:
     """Create text-to-speech service.
@@ -360,11 +361,11 @@ def create_tts_service(
 
 
 def create_realtime_llm_service(
-    model: Optional[str],
-    params: Optional[dict[str, Any]] = None,
-    agent: Optional[AgentConfig] = None,
-    audit_log: Optional[AuditLog] = None,
-    current_date_time: Optional[str] = None,
+    model: str | None,
+    params: dict[str, Any] | None = None,
+    agent: AgentConfig | None = None,
+    audit_log: AuditLog | None = None,
+    current_date_time: str | None = None,
 ) -> LLMService:
     """Create realtime LLM service.
 
diff --git a/src/eva/assistant/server.py b/src/eva/assistant/server.py
index 4282e894..5e920a15 100644
--- a/src/eva/assistant/server.py
+++ b/src/eva/assistant/server.py
@@ -8,7 +8,7 @@
 import json
 import wave
 from pathlib import Path
-from typing import Any, Optional
+from typing import Any
 
 import uvicorn
 from fastapi import FastAPI, WebSocket
@@ -135,7 +135,7 @@ def __init__(
         )
 
         # Wall-clock captured at on_user_turn_started for non-instrumented S2S models
-        self._user_turn_started_wall_ms: Optional[str] = None
+        self._user_turn_started_wall_ms: str | None = None
 
         # Audio buffer for accumulating audio data
         self._audio_buffer = bytearray()
@@ -147,12 +147,12 @@ def __init__(
         self._app = None
         self._server = None
         self._server_task = None
-        self._runner: Optional[PipelineRunner] = None
-        self._task: Optional[PipelineTask] = None
+        self._runner: PipelineRunner | None = None
+        self._task: PipelineTask | None = None
         self._running = False
         self.num_seconds = 0
         self._latency_measurements: list[float] = []
-        self._metrics_observer: Optional[MetricsFileObserver] = None
+        self._metrics_observer: MetricsFileObserver | None = None
         self.non_instrumented_realtime_llm = False
 
     async def start(self) -> None:
@@ -217,7 +217,7 @@ async def stop(self) -> None:
             if self._server_task:
                 try:
                     await asyncio.wait_for(self._server_task, timeout=5.0)
-                except asyncio.TimeoutError:
+                except TimeoutError:
                     # Force cancellation if graceful shutdown times out
                     self._server_task.cancel()
                     try:
diff --git a/src/eva/assistant/services/llm.py b/src/eva/assistant/services/llm.py
index 4d941304..9f329c5b 100644
--- a/src/eva/assistant/services/llm.py
+++ b/src/eva/assistant/services/llm.py
@@ -2,7 +2,7 @@
 
 import asyncio
 import time
-from typing import Any, Optional
+from typing import Any
 
 import litellm
 from dotenv import load_dotenv
@@ -37,7 +37,7 @@ def __init__(self, model: str):
     async def complete(
         self,
         messages: list[dict[str, Any]],
-        tools: Optional[list[dict]] = None,
+        tools: list[dict] | None = None,
         max_retries: int = 5,
         initial_delay: float = 1.0,
     ) -> tuple[Any, dict[str, Any]]:
diff --git a/src/eva/assistant/tools/airline_params.py b/src/eva/assistant/tools/airline_params.py
index 7173a74a..93238a7f 100644
--- a/src/eva/assistant/tools/airline_params.py
+++ b/src/eva/assistant/tools/airline_params.py
@@ -10,7 +10,7 @@
 """
 
 from enum import StrEnum
-from typing import Annotated, Optional
+from typing import Annotated
 
 from pydantic import BaseModel, Field, ValidationError
 
@@ -133,8 +133,8 @@ class RebookFlightParams(BaseModel):
     new_journey_id: JourneyIdStr
     rebooking_type: RebookingType
     waive_change_fee: bool
-    new_fare_class: Optional[FareClass] = None
-    flight_number: Optional[FlightNumberStr] = None
+    new_fare_class: FareClass | None = None
+    flight_number: FlightNumberStr | None = None
 
 
 class AddToStandbyParams(BaseModel):
@@ -148,14 +148,14 @@ class AssignSeatParams(BaseModel):
     passenger_id: PassengerIdStr
     journey_id: JourneyIdStr
     seat_preference: SeatPreference
-    flight_number: Optional[FlightNumberStr] = None
+    flight_number: FlightNumberStr | None = None
 
 
 class AddBaggageAllowanceParams(BaseModel):
     confirmation_number: ConfirmationNumber
     journey_id: JourneyIdStr
     num_bags: int = Field(ge=0, le=5)
-    flight_number: Optional[FlightNumberStr] = None
+    flight_number: FlightNumberStr | None = None
 
 
 class AddMealRequestParams(BaseModel):
@@ -163,7 +163,7 @@ class AddMealRequestParams(BaseModel):
     passenger_id: PassengerIdStr
     journey_id: JourneyIdStr
     meal_type: MealType
-    flight_number: Optional[FlightNumberStr] = None
+    flight_number: FlightNumberStr | None = None
 
 
 class IssueTravelCreditParams(BaseModel):
diff --git a/src/eva/assistant/tools/airline_tools.py b/src/eva/assistant/tools/airline_tools.py
index a07fbd95..2aee65a4 100644
--- a/src/eva/assistant/tools/airline_tools.py
+++ b/src/eva/assistant/tools/airline_tools.py
@@ -434,7 +434,7 @@ def rebook_flight(params: dict, db: dict, call_index: int) -> dict:
 
     # Determine fare classes
     original_fare_class = booking.get("fare_class", "main_cabin")
-    target_fare_class = new_fare_class if new_fare_class else original_fare_class
+    target_fare_class = new_fare_class or original_fare_class
 
     # Computations
     is_irrops = "irrops" in rebooking_type
diff --git a/src/eva/assistant/tools/tool_executor.py b/src/eva/assistant/tools/tool_executor.py
index 9722e514..32bd6c57 100644
--- a/src/eva/assistant/tools/tool_executor.py
+++ b/src/eva/assistant/tools/tool_executor.py
@@ -3,8 +3,8 @@
 import copy
 import importlib
 import json
+from collections.abc import Callable
 from pathlib import Path
-from typing import Callable
 
 import yaml
 from pipecat.services.llm_service import FunctionCallParams
diff --git a/src/eva/metrics/base.py b/src/eva/metrics/base.py
index 174273ff..ade4722b 100644
--- a/src/eva/metrics/base.py
+++ b/src/eva/metrics/base.py
@@ -4,7 +4,7 @@
 from abc import ABC, abstractmethod
 from enum import StrEnum
 from pathlib import Path
-from typing import Any, Optional
+from typing import Any
 
 from pydub import AudioSegment
 
@@ -61,13 +61,13 @@ def __init__(
         num_turns: int = 0,
         num_tool_calls: int = 0,
         tools_called: list[str] = None,
-        conversation_ended_reason: Optional[str] = None,
+        conversation_ended_reason: str | None = None,
         duration_seconds: float = 0.0,
         # Paths to files
         output_dir: str = "",
-        audio_assistant_path: Optional[str] = None,
-        audio_user_path: Optional[str] = None,
-        audio_mixed_path: Optional[str] = None,
+        audio_assistant_path: str | None = None,
+        audio_user_path: str | None = None,
+        audio_mixed_path: str | None = None,
         # Processed log data from postprocessor
         transcribed_assistant_turns: dict[int, str] | None = None,
         transcribed_user_turns: dict[int, str] | None = None,
diff --git a/src/eva/metrics/processor.py b/src/eva/metrics/processor.py
index ad4d5d6c..38fd6803 100644
--- a/src/eva/metrics/processor.py
+++ b/src/eva/metrics/processor.py
@@ -4,7 +4,6 @@
 from collections import Counter
 from dataclasses import dataclass, field
 from pathlib import Path
-from typing import Optional
 
 from eva.assistant.agentic.system import GENERIC_ERROR
 from eva.models.results import ConversationResult
@@ -647,7 +646,7 @@ class _ProcessorContext:
     """Processed log data for metric computation."""
 
     def __init__(self):
-        self.record_id: Optional[str] = None
+        self.record_id: str | None = None
 
         # Per-role turn data (indexed by turn_id, 0-indexed)
         self.transcribed_assistant_turns: dict[int, str] = {}
@@ -670,9 +669,9 @@ def __init__(self):
 
         self.conversation_trace: list[dict] = []
 
-        self.audio_assistant_path: Optional[str] = None
-        self.audio_user_path: Optional[str] = None
-        self.audio_mixed_path: Optional[str] = None
+        self.audio_assistant_path: str | None = None
+        self.audio_user_path: str | None = None
+        self.audio_mixed_path: str | None = None
 
         # Interruption data
         self.assistant_interrupted_turns: set[int] = set()
@@ -680,7 +679,7 @@ def __init__(self):
 
         # Conversation metadata
         self.conversation_finished: bool = False
-        self.conversation_ended_reason: Optional[str] = None
+        self.conversation_ended_reason: str | None = None
         self.is_audio_native: bool = False
 
         # Response latencies from Pipecat's UserBotLatencyObserver
@@ -698,7 +697,7 @@ def process_record(
         result: ConversationResult,
         output_dir: Path,
         is_audio_native: bool = False,
-    ) -> Optional[_ProcessorContext]:
+    ) -> _ProcessorContext | None:
         """Process a single conversation record to create metric context.
 
         Args:
diff --git a/src/eva/metrics/registry.py b/src/eva/metrics/registry.py
index 1eb0c2cd..5c6c87b6 100644
--- a/src/eva/metrics/registry.py
+++ b/src/eva/metrics/registry.py
@@ -1,6 +1,6 @@
 """Registry for managing available metrics."""
 
-from typing import Any, Type
+from typing import Any
 
 from eva.metrics.base import BaseMetric
 from eva.utils.logging import get_logger
@@ -15,9 +15,9 @@ class MetricRegistry:
     """
 
     def __init__(self):
-        self._metrics: dict[str, Type[BaseMetric]] = {}
+        self._metrics: dict[str, type[BaseMetric]] = {}
 
-    def register(self, metric_class: Type[BaseMetric]) -> Type[BaseMetric]:
+    def register(self, metric_class: type[BaseMetric]) -> type[BaseMetric]:
         """Register a metric class.
 
         Can be used as a decorator:
@@ -39,7 +39,7 @@ class MyMetric(BaseMetric):
         logger.debug(f"Registered metric: {name}")
         return metric_class
 
-    def get(self, name: str) -> Type[BaseMetric] | None:
+    def get(self, name: str) -> type[BaseMetric] | None:
         """Get a metric class by name.
 
         Args:
@@ -74,7 +74,7 @@ def list_metrics(self) -> list[str]:
         """Get list of all registered metric names."""
         return list(self._metrics.keys())
 
-    def get_all(self) -> dict[str, Type[BaseMetric]]:
+    def get_all(self) -> dict[str, type[BaseMetric]]:
         """Get all registered metrics."""
         return self._metrics.copy()
 
@@ -88,7 +88,7 @@ def get_global_registry() -> MetricRegistry:
     return _global_registry
 
 
-def register_metric(metric_class: Type[BaseMetric]) -> Type[BaseMetric]:
+def register_metric(metric_class: type[BaseMetric]) -> type[BaseMetric]:
     """Register a metric in the global registry.
 
     Decorator for metric classes.
diff --git a/src/eva/metrics/validation/conversation_finished.py b/src/eva/metrics/validation/conversation_finished.py
index 03e8a030..acd89f05 100644
--- a/src/eva/metrics/validation/conversation_finished.py
+++ b/src/eva/metrics/validation/conversation_finished.py
@@ -38,7 +38,7 @@ async def compute(self, context: MetricContext) -> MetricScore:
                     details={"file_path": str(elevenlabs_events_path)},
                 )
 
-            with open(elevenlabs_events_path, "r") as f:
+            with open(elevenlabs_events_path) as f:
                 lines = f.readlines()
 
             if not lines:
diff --git a/src/eva/models/agents.py b/src/eva/models/agents.py
index 09f3140d..e08fd030 100644
--- a/src/eva/models/agents.py
+++ b/src/eva/models/agents.py
@@ -1,7 +1,7 @@
 """Agent configuration models."""
 
 from pathlib import Path
-from typing import Any, Optional
+from typing import Any
 
 import yaml
 from pydantic import BaseModel, ConfigDict, Field
@@ -12,11 +12,11 @@ class AgentToolParameter(BaseModel):
 
     name: str = Field(..., description="Parameter name")
     type: str = Field("string", description="Parameter type")
-    enum: Optional[list[str]] = Field(None, description="Allowed values for enum types")
+    enum: list[str] | None = Field(None, description="Allowed values for enum types")
     description: str = Field("", description="Parameter description")
-    items: Optional[dict[str, Any]] = Field(None, description="Items schema for array types")
-    properties: Optional[dict[str, Any]] = Field(None, description="Properties schema for object types")
-    additionalProperties: Optional[bool | dict[str, Any]] = Field(
+    items: dict[str, Any] | None = Field(None, description="Items schema for array types")
+    properties: dict[str, Any] | None = Field(None, description="Properties schema for object types")
+    additionalProperties: bool | dict[str, Any] | None = Field(
         None, description="Additional properties for object types"
     )
 
@@ -30,7 +30,7 @@ class AgentTool(BaseModel):
     required_parameters: list[str | AgentToolParameter] = Field(default_factory=list, description="Required parameters")
     optional_parameters: list[str | AgentToolParameter] = Field(default_factory=list, description="Optional parameters")
     invoke_cache_flush: bool = Field(False, description="Whether to flush cache on invocation")
-    tool_type: Optional[str] = Field(None, description="Type of tool: 'read' or 'write'")
+    tool_type: str | None = Field(None, description="Type of tool: 'read' or 'write'")
     metadata: dict[str, Any] = Field(default_factory=dict, description="Additional metadata")
 
     model_config = ConfigDict(extra="allow")
@@ -104,7 +104,7 @@ class AgentConfig(BaseModel):
     role: str = Field(..., description="Agent role description")
     instructions: str = Field(..., description="Agent instructions/prompt")
     tools: list[AgentTool] = Field(default_factory=list, description="Tools available to this agent")
-    personality: Optional[str] = Field(None, description="Agent personality description")
+    personality: str | None = Field(None, description="Agent personality description")
     tool_module_path: str = Field(
         description="Python module path for tool implementations (e.g., 'eva.assistant.tools.airline_tools')",
     )
@@ -215,14 +215,14 @@ class AgentsConfig(BaseModel):
 
     agents: list[AgentConfig] = Field(default_factory=list, description="List of available agents")
 
-    def get_agent_by_id(self, agent_id: str) -> Optional[AgentConfig]:
+    def get_agent_by_id(self, agent_id: str) -> AgentConfig | None:
         """Get an agent by its ID."""
         for agent in self.agents:
             if agent.id == agent_id:
                 return agent
         return None
 
-    def get_agent_by_name(self, name: str) -> Optional[AgentConfig]:
+    def get_agent_by_name(self, name: str) -> AgentConfig | None:
         """Get an agent by its name."""
         for agent in self.agents:
             if agent.name == name:
diff --git a/src/eva/models/provenance.py b/src/eva/models/provenance.py
index 7828f164..d5228859 100644
--- a/src/eva/models/provenance.py
+++ b/src/eva/models/provenance.py
@@ -1,7 +1,6 @@
 """Provenance model for tracking run artifacts and environment."""
 
 from datetime import datetime
-from typing import Optional
 
 from pydantic import BaseModel, Field
 
@@ -19,14 +18,14 @@ class BaseProvenance(BaseModel):
     eva_version: str
     simulation_version: str = ""
     metrics_version: str = ""
-    git_commit_sha: Optional[str] = None
-    git_branch: Optional[str] = None
-    git_dirty: Optional[bool] = None
-    git_diff_hash: Optional[str] = None
-    dataset: Optional[ArtifactInfo] = None
-    agent_config: Optional[ArtifactInfo] = None
-    tool_module: Optional[ArtifactInfo] = None
-    scenario_db: Optional[ArtifactInfo] = None
+    git_commit_sha: str | None = None
+    git_branch: str | None = None
+    git_dirty: bool | None = None
+    git_diff_hash: str | None = None
+    dataset: ArtifactInfo | None = None
+    agent_config: ArtifactInfo | None = None
+    tool_module: ArtifactInfo | None = None
+    scenario_db: ArtifactInfo | None = None
     python_version: str = ""
     platform: str = ""
     captured_at: datetime = Field(default_factory=datetime.now)
diff --git a/src/eva/models/record.py b/src/eva/models/record.py
index 57563820..a0ca7a09 100644
--- a/src/eva/models/record.py
+++ b/src/eva/models/record.py
@@ -2,7 +2,7 @@
 
 import json
 from pathlib import Path
-from typing import Any, Optional
+from typing import Any
 
 from pydantic import BaseModel, ConfigDict, Field
 
@@ -99,9 +99,9 @@ class GroundTruth(BaseModel):
 class AgentOverride(BaseModel):
     """Override agent configuration for a specific record."""
 
-    instructions: Optional[str] = Field(None, description="Override agent instructions")
-    tools_enabled: Optional[list[str]] = Field(None, description="Subset of tools to enable")
-    personality: Optional[str] = Field(None, description="Override agent personality")
+    instructions: str | None = Field(None, description="Override agent instructions")
+    tools_enabled: list[str] | None = Field(None, description="Subset of tools to enable")
+    personality: str | None = Field(None, description="Override agent personality")
 
 
 class EvaluationRecord(BaseModel):
@@ -123,10 +123,10 @@ class EvaluationRecord(BaseModel):
     ground_truth: GroundTruth = Field(default_factory=GroundTruth, description="Expected outcomes for evaluation")
 
     # Optional overrides
-    agent_override: Optional[AgentOverride] = Field(None, description="Override agent configuration for this record")
+    agent_override: AgentOverride | None = Field(None, description="Override agent configuration for this record")
 
     # Metadata
-    category: Optional[str] = Field(None, description="Category for grouping, e.g., 'hr_pto', 'it_support'")
+    category: str | None = Field(None, description="Category for grouping, e.g., 'hr_pto', 'it_support'")
 
     @classmethod
     def load_dataset(cls, path: Path | str) -> list["EvaluationRecord"]:
@@ -145,5 +145,4 @@ def save_dataset(cls, records: list["EvaluationRecord"], path: Path | str) -> No
         """Save records to JSONL file."""
         path = Path(path)
         with open(path, "w", encoding="utf-8") as f:
-            for record in records:
-                f.write(record.model_dump_json() + "\n")
+            f.writelines(record.model_dump_json() + "\n" for record in records)
diff --git a/src/eva/models/results.py b/src/eva/models/results.py
index a10985f8..ef088813 100644
--- a/src/eva/models/results.py
+++ b/src/eva/models/results.py
@@ -2,7 +2,7 @@
 
 from dataclasses import dataclass
 from datetime import datetime
-from typing import Any, Optional
+from typing import Any
 
 from pydantic import BaseModel, Field
 
@@ -21,7 +21,7 @@ class ErrorDetails(BaseModel):
     retry_count: int = Field(0, description="Number of retry attempts")
     retry_succeeded: bool = Field(False, description="Whether retry succeeded")
     timestamps: list[str] = Field(default_factory=list, description="Timestamp of each attempt")
-    stack_trace: Optional[str] = Field(None, description="Stack trace if available")
+    stack_trace: str | None = Field(None, description="Stack trace if available")
     original_error: str = Field(..., description="Original error message")
 
 
@@ -40,15 +40,15 @@ class ConversationResult(BaseModel):
 
     record_id: str = Field(..., description="ID of the evaluation record")
     completed: bool = Field(..., description="Whether the conversation completed successfully")
-    error: Optional[str] = Field(None, description="Error message if failed")
-    error_details: Optional[ErrorDetails] = Field(
+    error: str | None = Field(None, description="Error message if failed")
+    error_details: ErrorDetails | None = Field(
         None, description="Detailed error information (new field, optional for backward compatibility)"
     )
 
     # Latency statistics
-    llm_latency: Optional[LatencyStats] = Field(None, description="LLM latency statistics")
-    stt_latency: Optional[LatencyStats] = Field(None, description="STT latency statistics")
-    tts_latency: Optional[LatencyStats] = Field(None, description="TTS latency statistics")
+    llm_latency: LatencyStats | None = Field(None, description="LLM latency statistics")
+    stt_latency: LatencyStats | None = Field(None, description="STT latency statistics")
+    tts_latency: LatencyStats | None = Field(None, description="TTS latency statistics")
 
     # Timing
     started_at: datetime = Field(..., description="When the conversation started")
@@ -57,25 +57,25 @@ class ConversationResult(BaseModel):
 
     # Paths to outputs
     output_dir: str = Field(..., description="Path to output directory for this record")
-    audio_assistant_path: Optional[str] = Field(None, description="Path to assistant audio file")
-    audio_user_path: Optional[str] = Field(None, description="Path to user audio file")
-    audio_mixed_path: Optional[str] = Field(None, description="Path to mixed audio file")
-    transcript_path: Optional[str] = Field(None, description="Path to transcript JSONL file")
-    audit_log_path: Optional[str] = Field(None, description="Path to audit log JSON file")
-    conversation_log_path: Optional[str] = Field(None, description="Path to conversation log file")
-    pipecat_logs_path: Optional[str] = Field(None, description="Path to pipecat logs JSONL file")
-    elevenlabs_logs_path: Optional[str] = Field(None, description="Path to elevenlabs logs JSONL file")
+    audio_assistant_path: str | None = Field(None, description="Path to assistant audio file")
+    audio_user_path: str | None = Field(None, description="Path to user audio file")
+    audio_mixed_path: str | None = Field(None, description="Path to mixed audio file")
+    transcript_path: str | None = Field(None, description="Path to transcript JSONL file")
+    audit_log_path: str | None = Field(None, description="Path to audit log JSON file")
+    conversation_log_path: str | None = Field(None, description="Path to conversation log file")
+    pipecat_logs_path: str | None = Field(None, description="Path to pipecat logs JSONL file")
+    elevenlabs_logs_path: str | None = Field(None, description="Path to elevenlabs logs JSONL file")
 
     # Summary stats (pre-metrics)
     num_turns: int = Field(0, description="Number of conversation turns")
     num_tool_calls: int = Field(0, description="Number of tool calls made")
     tools_called: list[str] = Field(default_factory=list, description="List of tools that were called")
-    conversation_ended_reason: Optional[str] = Field(
+    conversation_ended_reason: str | None = Field(
         None,
         description="Reason conversation ended: 'goodbye', 'timeout', 'transfer', 'error'",
     )
-    initial_scenario_db_hash: Optional[str] = Field(None, description="SHA-256 hash of initial scenario database")
-    final_scenario_db_hash: Optional[str] = Field(None, description="SHA-256 hash of final scenario database")
+    initial_scenario_db_hash: str | None = Field(None, description="SHA-256 hash of initial scenario database")
+    final_scenario_db_hash: str | None = Field(None, description="SHA-256 hash of final scenario database")
 
 
 class MetricScore(BaseModel):
@@ -108,16 +108,14 @@ class RecordMetrics(BaseModel):
     model_config = {"extra": "allow"}  # Allow extra fields for backwards compatibility
 
     record_id: str = Field(..., description="ID of the evaluation record")
-    context: Optional[dict[str, Any]] = Field(
-        default=None, description="MetricContext fields used for computing metrics"
-    )
+    context: dict[str, Any] | None = Field(default=None, description="MetricContext fields used for computing metrics")
     metrics: dict[str, MetricScore] = Field(default_factory=dict, description="Metrics keyed by metric name")
     aggregate_metrics: dict[str, float | None] = Field(
         default_factory=dict,
         description="EVA composite aggregate scores (EVA-A, EVA-X, EVA-overall)",
     )
 
-    def get_score(self, metric_name: str) -> Optional[float]:
+    def get_score(self, metric_name: str) -> float | None:
         """Get the normalized score for a metric, falling back to raw score."""
         if metric_name not in self.metrics:
             return None
@@ -126,7 +124,7 @@ def get_score(self, metric_name: str) -> Optional[float]:
             return None
         return metric.normalized_score if metric.normalized_score is not None else metric.score
 
-    def get_context_field(self, field_name: str) -> Optional[Any]:
+    def get_context_field(self, field_name: str) -> Any | None:
         """Safely get a field from context."""
         if self.context and isinstance(self.context, dict):
             return self.context.get(field_name)
diff --git a/src/eva/orchestrator/port_pool.py b/src/eva/orchestrator/port_pool.py
index 0b118af8..ec86cfb7 100644
--- a/src/eva/orchestrator/port_pool.py
+++ b/src/eva/orchestrator/port_pool.py
@@ -1,7 +1,6 @@
 """Port pool for managing WebSocket server ports."""
 
 import asyncio
-from typing import Optional
 
 from eva.utils.logging import get_logger
 
@@ -46,7 +45,7 @@ async def initialize(self) -> None:
                 f"(range: {self.base_port}-{self.base_port + self.pool_size - 1})"
             )
 
-    async def acquire(self, timeout: Optional[float] = None) -> int:
+    async def acquire(self, timeout: float | None = None) -> int:
         """Acquire an available port from the pool.
 
         Args:
@@ -71,7 +70,7 @@ async def acquire(self, timeout: Optional[float] = None) -> int:
             logger.debug(f"Acquired port {port} ({len(self._in_use)} in use)")
             return port
 
-        except asyncio.TimeoutError:
+        except TimeoutError:
             logger.warning(f"Timeout waiting for available port (timeout={timeout}s)")
             raise
 
@@ -107,10 +106,10 @@ def is_port_in_use(self, port: int) -> bool:
 class PortPoolContextManager:
     """Context manager for acquiring and releasing ports."""
 
-    def __init__(self, pool: PortPool, timeout: Optional[float] = None):
+    def __init__(self, pool: PortPool, timeout: float | None = None):
         self.pool = pool
         self.timeout = timeout
-        self.port: Optional[int] = None
+        self.port: int | None = None
 
     async def __aenter__(self) -> int:
         self.port = await self.pool.acquire(timeout=self.timeout)
diff --git a/src/eva/orchestrator/runner.py b/src/eva/orchestrator/runner.py
index ac5a45f3..590d0828 100644
--- a/src/eva/orchestrator/runner.py
+++ b/src/eva/orchestrator/runner.py
@@ -954,16 +954,15 @@ def _save_results_csv(
             f.write("record_id,completed,duration_seconds,num_turns,num_tool_calls,ended_reason,error\n")
 
             # Successful records
-            for output_id, result in successful:
-                f.write(
-                    f"{output_id},true,{result.duration_seconds:.2f},"
-                    f"{result.num_turns},{result.num_tool_calls},"
-                    f"{result.conversation_ended_reason or ''},\n"
-                )
+            f.writelines(
+                f"{output_id},true,{result.duration_seconds:.2f},"
+                f"{result.num_turns},{result.num_tool_calls},"
+                f"{result.conversation_ended_reason or ''},\n"
+                for output_id, result in successful
+            )
 
             # Failed records
-            for record_id in failed_ids:
-                f.write(f"{record_id},false,0,0,0,error,failed\n")
+            f.writelines(f"{record_id},false,0,0,0,error,failed\n" for record_id in failed_ids)
 
     @classmethod
     def from_config_file(cls, config_path: Path | str) -> "BenchmarkRunner":
diff --git a/src/eva/orchestrator/worker.py b/src/eva/orchestrator/worker.py
index bf549d6b..9f96ba2d 100644
--- a/src/eva/orchestrator/worker.py
+++ b/src/eva/orchestrator/worker.py
@@ -5,7 +5,7 @@
 import math
 from datetime import datetime
 from pathlib import Path
-from typing import Any, Optional
+from typing import Any
 
 from eva.assistant.server import AssistantServer
 from eva.models.agents import AgentConfig
@@ -106,9 +106,9 @@ async def run(self) -> ConversationResult:
 
         logger.info(f"Starting conversation for record {self.record.id} on port {self.port}")
 
-        conversation_ended_reason: Optional[str] = None
-        error: Optional[str] = None
-        error_details: Optional[ErrorDetails] = None
+        conversation_ended_reason: str | None = None
+        error: str | None = None
+        error_details: ErrorDetails | None = None
 
         try:
             # 1. Start assistant server
@@ -126,7 +126,7 @@ async def run(self) -> ConversationResult:
                     timeout=self.config.conversation_timeout_seconds,
                 )
                 logger.info(f"Conversation {self.record.id} ended: {conversation_ended_reason}")
-            except asyncio.TimeoutError:
+            except TimeoutError:
                 conversation_ended_reason = "timeout"
                 logger.warning(f"Conversation {self.record.id} timed out")
             except asyncio.CancelledError:
@@ -288,7 +288,7 @@ async def _cleanup(self) -> None:
         if self._user_simulator:
             self._user_simulator = None
 
-    def _calculate_stt_latency(self) -> Optional[LatencyStats]:
+    def _calculate_stt_latency(self) -> LatencyStats | None:
         """Calculate STT latency statistics from Pipecat metrics.
 
         Uses ProcessingMetricsData from pipecat_metrics.jsonl, which measures
@@ -330,7 +330,7 @@ def _calculate_stt_latency(self) -> Optional[LatencyStats]:
             logger.warning(f"Failed to calculate STT latency: {e}")
             return None
 
-    def _calculate_tts_latency(self) -> Optional[LatencyStats]:
+    def _calculate_tts_latency(self) -> LatencyStats | None:
         """Calculate TTS latency statistics from Pipecat metrics.
 
         Uses TTFBMetricsData (Time To First Byte) from pipecat_metrics.jsonl,
@@ -375,7 +375,7 @@ def _calculate_tts_latency(self) -> Optional[LatencyStats]:
             logger.warning(f"Failed to calculate TTS latency: {e}")
             return None
 
-    def _calculate_llm_latency(self) -> Optional[LatencyStats]:
+    def _calculate_llm_latency(self) -> LatencyStats | None:
         """Calculate LLM latency statistics from audit log.
 
         LLM latency = time from LLM call start to response completion
diff --git a/src/eva/user_simulator/audio_interface.py b/src/eva/user_simulator/audio_interface.py
index 2dcee112..b8e0ec0b 100644
--- a/src/eva/user_simulator/audio_interface.py
+++ b/src/eva/user_simulator/audio_interface.py
@@ -10,7 +10,7 @@
 import asyncio
 import base64
 import json
-from typing import Callable, Optional
+from collections.abc import Callable
 
 import websockets
 from websockets.protocol import State as WebSocketState
@@ -71,9 +71,9 @@ def __init__(
         self,
         websocket_uri: str,
         conversation_id: str,
-        record_callback: Optional[Callable[[str, bytes], None]] = None,
+        record_callback: Callable[[str, bytes], None] | None = None,
         event_logger=None,
-        conversation_done_callback: Optional[Callable[[str], None]] = None,
+        conversation_done_callback: Callable[[str], None] | None = None,
     ):
         """Initialize the audio interface.
 
@@ -447,7 +447,7 @@ async def _continuous_input_stream(self) -> None:
                         chunk = await asyncio.wait_for(self.audio_buffer.get(), timeout=timeout)
                         audio_chunk += chunk
                         consecutive_empty_chunks = 0  # Reset on successful audio
-                    except asyncio.TimeoutError:
+                    except TimeoutError:
                         # In silence mode with short timeout, keep trying until chunk duration elapsed
                         if consecutive_empty_chunks > 0 and remaining_time > NORMAL_POLL_TIMEOUT_S:
                             continue
@@ -597,7 +597,7 @@ async def _send_to_assistant(self) -> None:
                         # Reset silence timing when transitioning to audio
                         silence_start_time = None
                         silence_chunks_sent = 0
-                except asyncio.TimeoutError:
+                except TimeoutError:
                     pass
 
                 # Refresh current_time after queue wait for accurate timing
diff --git a/src/eva/user_simulator/client.py b/src/eva/user_simulator/client.py
index 51946a48..ff8aa29f 100644
--- a/src/eva/user_simulator/client.py
+++ b/src/eva/user_simulator/client.py
@@ -8,7 +8,6 @@
 import json
 import os
 from pathlib import Path
-from typing import Optional
 
 import httpx
 from elevenlabs.client import ElevenLabs
@@ -65,7 +64,7 @@ def __init__(
 
         # State
         self._conversation = None
-        self._audio_interface: Optional[BotToBotAudioInterface] = None
+        self._audio_interface: BotToBotAudioInterface | None = None
         self._end_reason: str = "unknown"
         self._conversation_done = asyncio.Event()
 
@@ -203,7 +202,7 @@ async def _run_elevenlabs_conversation(self, api_key: str) -> str:
             try:
                 await asyncio.wait_for(self._conversation_done.wait(), timeout=self.timeout)
                 logger.info(f"Conversation ended: {self._end_reason}")
-            except asyncio.TimeoutError:
+            except TimeoutError:
                 logger.info(f"Conversation timed out after {self.timeout}s")
                 self._end_reason = "timeout"
                 self.event_logger.log_event("timeout", {"duration": self.timeout})
diff --git a/src/eva/user_simulator/event_logger.py b/src/eva/user_simulator/event_logger.py
index 2b22d101..c1183e2c 100644
--- a/src/eva/user_simulator/event_logger.py
+++ b/src/eva/user_simulator/event_logger.py
@@ -147,8 +147,7 @@ def save(self) -> None:
         self.output_path.parent.mkdir(parents=True, exist_ok=True)
 
         with open(self.output_path, "w") as f:
-            for event in self._events:
-                f.write(json.dumps(event) + "\n")
+            f.writelines(json.dumps(event) + "\n" for event in self._events)
 
         logger.info(f"Saved {len(self._events)} ElevenLabs events to {self.output_path}")
 
diff --git a/src/eva/utils/__init__.py b/src/eva/utils/__init__.py
index 179a1af5..273f5d6d 100644
--- a/src/eva/utils/__init__.py
+++ b/src/eva/utils/__init__.py
@@ -2,7 +2,6 @@
 
 import logging
 import sys
-from typing import Optional
 
 
 def get_logger(name: str) -> logging.Logger:
@@ -19,8 +18,8 @@ def get_logger(name: str) -> logging.Logger:
 
 def setup_logging(
     level: str = "INFO",
-    log_file: Optional[str] = None,
-    format_string: Optional[str] = None,
+    log_file: str | None = None,
+    format_string: str | None = None,
 ) -> None:
     """Set up logging configuration for the application.
 
diff --git a/src/eva/utils/error_handler.py b/src/eva/utils/error_handler.py
index 7cf38746..4c7e8b1b 100644
--- a/src/eva/utils/error_handler.py
+++ b/src/eva/utils/error_handler.py
@@ -7,8 +7,7 @@
 import asyncio
 import traceback
 from dataclasses import dataclass
-from datetime import datetime, timezone
-from typing import Optional
+from datetime import UTC, datetime
 
 from litellm.exceptions import (
     # Network/Connection Errors
@@ -46,7 +45,7 @@ class ErrorInfo:
     error_type: str  # Maps to ErrorDetails.error_type
     error_source: str  # Provider or component name
     is_retryable: bool
-    status_code: Optional[int]
+    status_code: int | None
     original_exception: Exception
 
 
@@ -353,7 +352,7 @@ def create_error_details(
         is_retryable=error_info.is_retryable,
         retry_count=retry_count,
         retry_succeeded=retry_succeeded,
-        timestamps=[datetime.now(timezone.utc).isoformat()],
+        timestamps=[datetime.now(UTC).isoformat()],
         stack_trace=stack_trace,
         original_error=str(error),
     )
diff --git a/src/eva/utils/llm_client.py b/src/eva/utils/llm_client.py
index dd949982..8d9fb1ad 100644
--- a/src/eva/utils/llm_client.py
+++ b/src/eva/utils/llm_client.py
@@ -3,7 +3,7 @@
 import asyncio
 import itertools
 import random
-from typing import ClassVar, Optional
+from typing import ClassVar
 
 from dotenv import load_dotenv
 
@@ -88,7 +88,7 @@ def _calculate_backoff_delay(self, attempt: int) -> float:
         # Ensure delay is positive
         return max(0, delay)
 
-    async def generate_text(self, messages: list[dict], response_format: Optional[dict] = None) -> str:
+    async def generate_text(self, messages: list[dict], response_format: dict | None = None) -> str:
         """Generate text completion with automatic retries.
 
         Args:
diff --git a/src/eva/utils/logging.py b/src/eva/utils/logging.py
index dfc8b8cb..71c78fd0 100644
--- a/src/eva/utils/logging.py
+++ b/src/eva/utils/logging.py
@@ -3,7 +3,6 @@
 import contextvars
 import logging
 import sys
-from typing import Optional
 
 # ContextVar that tracks which record_id the current asyncio task is processing.
 # Each ConversationWorker sets this at the start of its run() method.
@@ -47,8 +46,8 @@ def get_logger(name: str) -> logging.Logger:
 
 def setup_logging(
     level: str = "INFO",
-    log_file: Optional[str] = None,
-    format_string: Optional[str] = None,
+    log_file: str | None = None,
+    format_string: str | None = None,
 ) -> None:
     """Set up logging configuration for the application.
 
diff --git a/src/eva/utils/prompt_manager.py b/src/eva/utils/prompt_manager.py
index 56971149..c67db941 100644
--- a/src/eva/utils/prompt_manager.py
+++ b/src/eva/utils/prompt_manager.py
@@ -10,7 +10,7 @@
 """
 
 from pathlib import Path
-from typing import Any, Optional
+from typing import Any
 
 import yaml
 
@@ -36,7 +36,7 @@ class PromptManager:
         ... )
     """
 
-    def __init__(self, prompts_path: Optional[Path | str] = None):
+    def __init__(self, prompts_path: Path | str | None = None):
         """Initialize the prompt manager.
 
         Args:
@@ -63,7 +63,7 @@ def _load_prompts(self) -> None:
     def _load_single_file(self, file_path: Path) -> None:
         """Load prompts from a single YAML file."""
         try:
-            with open(file_path, "r", encoding="utf-8") as f:
+            with open(file_path, encoding="utf-8") as f:
                 data = yaml.safe_load(f) or {}
             self.prompts.update(data)
             self.loaded_files.append(file_path)
@@ -126,7 +126,7 @@ def get_prompt(self, path: str, **variables) -> str:
 
 
 # Global singleton instance
-_prompt_manager: Optional[PromptManager] = None
+_prompt_manager: PromptManager | None = None
 
 
 def get_prompt_manager() -> PromptManager:
diff --git a/src/eva/utils/provenance.py b/src/eva/utils/provenance.py
index c66188ca..259eee71 100644
--- a/src/eva/utils/provenance.py
+++ b/src/eva/utils/provenance.py
@@ -6,7 +6,6 @@
 import subprocess
 import sys
 from pathlib import Path
-from typing import Optional
 
 import eva
 from eva.models.config import RunConfig
@@ -17,7 +16,7 @@
 logger = get_logger(__name__)
 
 
-def _run_git_command(args: list[str]) -> Optional[str]:
+def _run_git_command(args: list[str]) -> str | None:
     """Run a git command and return stripped stdout, or None on failure."""
     try:
         result = subprocess.run(
@@ -35,7 +34,7 @@ def _run_git_command(args: list[str]) -> Optional[str]:
 
 def _get_git_info() -> dict:
     """Collect git state information."""
-    info: dict[str, Optional[str | bool]] = {
+    info: dict[str, str | bool | None] = {
         "git_commit_sha": None,
         "git_branch": None,
         "git_dirty": None,
@@ -59,7 +58,7 @@ def _get_git_info() -> dict:
     return info
 
 
-def _find_project_root() -> Optional[Path]:
+def _find_project_root() -> Path | None:
     """Find project root by searching up from this file for pyproject.toml."""
     current = Path(__file__).resolve().parent
     for parent in [current, *current.parents]:
@@ -68,7 +67,7 @@ def _find_project_root() -> Optional[Path]:
     return None
 
 
-def resolve_tool_module_file(tool_module_path: Optional[str]) -> Optional[Path]:
+def resolve_tool_module_file(tool_module_path: str | None) -> Path | None:
     """Resolve a Python module path to its filesystem path."""
     if not tool_module_path:
         return None
@@ -83,7 +82,7 @@ def resolve_tool_module_file(tool_module_path: Optional[str]) -> Optional[Path]:
 
 def capture_provenance(
     config: RunConfig,
-    tool_module_file: Optional[Path] = None,
+    tool_module_file: Path | None = None,
 ) -> RunProvenance:
     """Capture full provenance for a benchmark run.
 
@@ -130,7 +129,7 @@ def _relative_path(path: Path) -> str:
     else:
         logger.warning("Could not find configs/prompts/ directory for provenance")
 
-    tool_module_info: Optional[ArtifactInfo] = None
+    tool_module_info: ArtifactInfo | None = None
     if tool_module_file is None:
         tool_module_file = resolve_tool_module_file(config.tool_module_path)
     if tool_module_file and tool_module_file.exists():
@@ -173,7 +172,7 @@ def _relative_path(path: Path) -> str:
 
 def capture_metrics_provenance(
     metric_names: list[str],
-    run_config: Optional[dict] = None,
+    run_config: dict | None = None,
 ) -> MetricsProvenance:
     """Capture provenance for a metrics computation run.
 
@@ -188,7 +187,7 @@ def capture_metrics_provenance(
     git_info = _get_git_info()
     project_root = _find_project_root()
 
-    def _make_artifact(path_str: Optional[str], is_dir: bool = False) -> Optional[ArtifactInfo]:
+    def _make_artifact(path_str: str | None, is_dir: bool = False) -> ArtifactInfo | None:
         if not path_str:
             return None
         path = Path(path_str)
@@ -200,10 +199,10 @@ def _make_artifact(path_str: Optional[str], is_dir: bool = False) -> Optional[Ar
         sha = hash_directory(path) if is_dir else hash_file(path)
         return ArtifactInfo(path=path_str, sha256=sha)
 
-    dataset_info: Optional[ArtifactInfo] = None
-    agent_config_info: Optional[ArtifactInfo] = None
-    tool_module_info: Optional[ArtifactInfo] = None
-    scenario_db_info: Optional[ArtifactInfo] = None
+    dataset_info: ArtifactInfo | None = None
+    agent_config_info: ArtifactInfo | None = None
+    tool_module_info: ArtifactInfo | None = None
+    scenario_db_info: ArtifactInfo | None = None
 
     if run_config:
         dataset_info = _make_artifact(run_config.get("dataset_path"))
diff --git a/tests/unit/conftest.py b/tests/unit/conftest.py
index 72e0f49b..2ed400e0 100644
--- a/tests/unit/conftest.py
+++ b/tests/unit/conftest.py
@@ -106,8 +106,7 @@ def dataset_file(temp_dir, sample_record_data):
     """Create a temporary dataset JSONL file."""
     path = temp_dir / "dataset.jsonl"
     with open(path, "w") as f:
-        for record in sample_record_data:
-            f.write(json.dumps(record) + "\n")
+        f.writelines(json.dumps(record) + "\n" for record in sample_record_data)
     return path
 
 
diff --git a/tests/unit/metrics/test_conversation_finished.py b/tests/unit/metrics/test_conversation_finished.py
index e370a4be..0e0c247f 100644
--- a/tests/unit/metrics/test_conversation_finished.py
+++ b/tests/unit/metrics/test_conversation_finished.py
@@ -16,8 +16,7 @@ def _write_events(self, tmp_path, events: list[dict]) -> str:
         """Write events to elevenlabs_events.jsonl and return output_dir."""
         events_file = tmp_path / "elevenlabs_events.jsonl"
         with open(events_file, "w") as f:
-            for event in events:
-                f.write(json.dumps(event) + "\n")
+            f.writelines(json.dumps(event) + "\n" for event in events)
         return str(tmp_path)
 
     @pytest.mark.asyncio
diff --git a/tests/unit/utils/test_error_handler.py b/tests/unit/utils/test_error_handler.py
index fc2aef53..498cc59a 100644
--- a/tests/unit/utils/test_error_handler.py
+++ b/tests/unit/utils/test_error_handler.py
@@ -1,7 +1,5 @@
 """Tests for eva.utils.error_handler module."""
 
-import asyncio
-
 import httpx
 import pytest
 from litellm.exceptions import (
@@ -137,7 +135,7 @@ def test_generic_api_error(self):
         assert info.is_retryable is True
 
     def test_asyncio_timeout(self):
-        err = asyncio.TimeoutError()
+        err = TimeoutError()
         info = categorize_error(err)
         assert info.error_type == "timeout_error"
         assert info.error_source == "system"
@@ -201,7 +199,7 @@ def test_llm_provider_attribute(self):
         assert get_error_source(err) == "openai"
 
     def test_asyncio_timeout(self):
-        assert get_error_source(asyncio.TimeoutError()) == "system"
+        assert get_error_source(TimeoutError()) == "system"
 
     def test_tts_providers(self):
         assert get_error_source(Exception("cartesia error")) == "cartesia"
@@ -229,7 +227,7 @@ def test_retryable_litellm_errors(self, cls):
         assert is_retryable_error(err) is True
 
     def test_asyncio_timeout_retryable(self):
-        assert is_retryable_error(asyncio.TimeoutError()) is True
+        assert is_retryable_error(TimeoutError()) is True
 
     def test_tts_stt_retryable(self):
         assert is_retryable_error(Exception("cartesia error")) is True