Reasoning

"""Reasoning agent: emits AG-UI REASONING_MESSAGE_* events.Shared by reasoning-default (CopilotKit's built-in reasoning slot) andreasoning-custom (a custom amber ReasoningBlock).Why a reasoning model plus the Responses API: the OpenAI Responses API streams`response.reasoning_summary_text.delta` items only for native reasoning models(gpt-5, o3, o4-mini and friends). The Strands bridge translates those intoAG-UI REASONING_MESSAGE_* events with `role: "reasoning"`, which the frontendrenders through the `reasoningMessage` slot. gpt-4o emits no reasoning items, sothe showcase's default chat-completions model would never light the slot up.`summary: "detailed"` rather than `"auto"` is deliberate: with `"auto"` themodel decides, and it frequently skips the summary entirely, which leaves thereasoning slot unmounted. Override the model with `OPENAI_REASONING_MODEL`.Mirrors `langgraph-python/src/agents/reasoning_agent.py`."""from __future__ import annotationsimport osfrom strands import Agentfrom ag_ui_strands import StrandsAgentSYSTEM_PROMPT = (    "You are a helpful assistant. For each user question, first think "    "step-by-step about the approach, then give a concise answer.")DEFAULT_REASONING_MODEL = "gpt-5.4"def reasoning_model_id() -> str:    """Resolve the reasoning model at call time.    Read here rather than at module scope: the agent server imports this module    before it calls `load_dotenv()`, so a module-level read would always miss an    `OPENAI_REASONING_MODEL` set in `.env`.    """    return os.environ.get("OPENAI_REASONING_MODEL", DEFAULT_REASONING_MODEL)def build_reasoning_model():    """Construct the Responses-API model that streams reasoning summaries.    `OpenAIResponsesModel` is imported here rather than at module scope so the    dependency shows up where it is used; it needs openai>=2, which the pinned    requirements provide. The agent server builds these agents at import time,    so an older install still fails the whole server, not just these demos.    """    from strands.models.openai_responses import OpenAIResponsesModel    api_key = os.getenv("OPENAI_API_KEY", "")    if not api_key:        raise RuntimeError("OPENAI_API_KEY must be set for the strands showcase agent")    return OpenAIResponsesModel(        client_args={"api_key": api_key},        model_id=reasoning_model_id(),        params={"reasoning": {"effort": "medium", "summary": "detailed"}},    )def build_reasoning_agent() -> StrandsAgent:    """Construct the tool-free StrandsAgent backing both reasoning demos."""    strands_agent = Agent(        model=build_reasoning_model(),        system_prompt=SYSTEM_PROMPT,        tools=[],    )    return StrandsAgent(        agent=strands_agent,        name="reasoning",        description="Strands agent that streams reasoning summaries alongside its answer",    )

"""Reasoning agent: emits AG-UI REASONING_MESSAGE_* events.Shared by reasoning-default (CopilotKit's built-in reasoning slot) andreasoning-custom (a custom amber ReasoningBlock).Why a reasoning model plus the Responses API: the OpenAI Responses API streams`response.reasoning_summary_text.delta` items only for native reasoning models(gpt-5, o3, o4-mini and friends). The Strands bridge translates those intoAG-UI REASONING_MESSAGE_* events with `role: "reasoning"`, which the frontendrenders through the `reasoningMessage` slot. gpt-4o emits no reasoning items, sothe showcase's default chat-completions model would never light the slot up.`summary: "detailed"` rather than `"auto"` is deliberate: with `"auto"` themodel decides, and it frequently skips the summary entirely, which leaves thereasoning slot unmounted. Override the model with `OPENAI_REASONING_MODEL`.Mirrors `langgraph-python/src/agents/reasoning_agent.py`."""from __future__ import annotationsimport osfrom strands import Agentfrom ag_ui_strands import StrandsAgentSYSTEM_PROMPT = (    "You are a helpful assistant. For each user question, first think "    "step-by-step about the approach, then give a concise answer.")DEFAULT_REASONING_MODEL = "gpt-5.4"def reasoning_model_id() -> str:    """Resolve the reasoning model at call time.    Read here rather than at module scope: the agent server imports this module    before it calls `load_dotenv()`, so a module-level read would always miss an    `OPENAI_REASONING_MODEL` set in `.env`.    """    return os.environ.get("OPENAI_REASONING_MODEL", DEFAULT_REASONING_MODEL)def build_reasoning_model():    """Construct the Responses-API model that streams reasoning summaries.    `OpenAIResponsesModel` is imported here rather than at module scope so the    dependency shows up where it is used; it needs openai>=2, which the pinned    requirements provide. The agent server builds these agents at import time,    so an older install still fails the whole server, not just these demos.    """    from strands.models.openai_responses import OpenAIResponsesModel    api_key = os.getenv("OPENAI_API_KEY", "")    if not api_key:        raise RuntimeError("OPENAI_API_KEY must be set for the strands showcase agent")    return OpenAIResponsesModel(        client_args={"api_key": api_key},        model_id=reasoning_model_id(),        params={"reasoning": {"effort": "medium", "summary": "detailed"}},    )def build_reasoning_agent() -> StrandsAgent:    """Construct the tool-free StrandsAgent backing both reasoning demos."""    strands_agent = Agent(        model=build_reasoning_model(),        system_prompt=SYSTEM_PROMPT,        tools=[],    )    return StrandsAgent(        agent=strands_agent,        name="reasoning",        description="Strands agent that streams reasoning summaries alongside its answer",    )