feat(patterns): add AG-UI LangGraph and Strands single-agent patterns

- Add agui-langgraph-single-agent pattern with LangGraph, Gateway MCP tools, and Memory integration
- Add agui-strands-single-agent pattern with Strands framework support
- Add PatchedLangGraphAgent for AG-UI SSE event streaming compatibility (bug-fix)
- Update auth utilities to support AG-UI request context and user ID extraction

Author: razkenari

patterns/agui-langgraph-single-agent/Dockerfile

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+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+FROM ghcr.io/astral-sh/uv:python3.13-bookworm-slim
+
+WORKDIR /app
+
+# Configure UV for container environment
+ENV UV_SYSTEM_PYTHON=1 \
+    UV_COMPILE_BYTECODE=1 \
+    DOCKER_CONTAINER=1 \
+    OTEL_PYTHON_LOG_CORRELATION=true \
+    PYTHONUNBUFFERED=1
+
+# Copy pyproject.toml and gateway package for FAST installation
+COPY pyproject.toml .
+COPY gateway/ gateway/
+COPY tools/ tools/
+
+# Copy and install agent-specific requirements first
+COPY patterns/agui-langgraph-single-agent/requirements.txt requirements.txt
+RUN uv pip install --no-cache -r requirements.txt && \
+    uv pip install --no-cache aws-opentelemetry-distro==0.10.1
+
+# Install FAST package with only core dependencies (no dev/agent optional deps)
+RUN uv pip install --no-cache -e . --no-deps && \
+    uv pip install --no-cache requests>=2.31.0
+
+# Create non-root user
+RUN useradd -m -u 1000 bedrock_agentcore
+USER bedrock_agentcore
+
+EXPOSE 8080
+
+# Copy only the agent code
+COPY patterns/agui-langgraph-single-agent/langgraph_agent.py .
+COPY patterns/agui-langgraph-single-agent/patched_langgraph_agent.py .
+COPY patterns/langgraph-single-agent/langgraph_code_interpreter.py .
+COPY patterns/utils/ utils/
+
+# Healthcheck using Python (no extra dependencies needed)
+HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+  CMD python -c "import urllib.request; urllib.request.urlopen('http://localhost:8080/ping', timeout=2)" || exit 1
+
+# AG-UI uses FastAPI/uvicorn, not BedrockAgentCoreApp
+CMD ["opentelemetry-instrument", "uvicorn", "langgraph_agent:app", "--host", "0.0.0.0", "--port", "8080"]

patterns/agui-langgraph-single-agent/__init__.py

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+"""AG-UI LangGraph single agent with Gateway MCP tools and Memory.
+
+Uses ag-ui-langgraph to produce native AG-UI SSE events.
+AgentCore proxies these unchanged when deployed with --protocol AGUI.
+"""
+
+import logging
+import os
+
+from fastapi import FastAPI, Request
+from fastapi.responses import StreamingResponse
+
+from ag_ui.core.types import RunAgentInput
+from ag_ui.encoder import EventEncoder
+from ag_ui_langgraph import LangGraphAgent
+
+from langgraph.prebuilt import create_react_agent
+from langchain_aws import ChatBedrock
+from langchain_mcp_adapters.client import MultiServerMCPClient
+from langgraph_checkpoint_aws import AgentCoreMemorySaver
+
+from bedrock_agentcore.identity.auth import requires_access_token
+from utils.auth import extract_user_id_from_request, setup_agentcore_context
+from utils.ssm import get_ssm_parameter
+from patched_langgraph_agent import PatchedLangGraphAgent
+
+logger = logging.getLogger(__name__)
+
+
+@requires_access_token(
+    provider_name=os.environ["GATEWAY_CREDENTIAL_PROVIDER_NAME"],
+    auth_flow="M2M",
+    scopes=[]
+)
+async def _fetch_gateway_token(access_token: str) -> str:
+    return access_token
+
+
+async def create_gateway_mcp_client() -> MultiServerMCPClient:
+    stack_name = os.environ.get("STACK_NAME")
+    if not stack_name:
+        raise ValueError("STACK_NAME environment variable is required")
+    if not stack_name.replace("-", "").replace("_", "").isalnum():
+        raise ValueError("Invalid STACK_NAME format")
+
+    gateway_url = get_ssm_parameter(f"/{stack_name}/gateway_url")
+    logger.info("[AGUI-LG] Gateway URL: %s", gateway_url)
+
+    fresh_token = await _fetch_gateway_token()
+    logger.info("[AGUI-LG] Gateway token fetched (%d chars)", len(fresh_token))
+    return MultiServerMCPClient({
+        "gateway": {
+            "transport": "streamable_http",
+            "url": gateway_url,
+            "headers": {"Authorization": f"Bearer {fresh_token}"}
+        }
+    })
+
+
+async def create_agent(user_id: str) -> LangGraphAgent:
+    system_prompt = """You are a helpful assistant with access to tools via the Gateway.
+    When asked about your tools, list them and explain what they do."""
+
+    bedrock_model = ChatBedrock(
+        model_id="us.anthropic.claude-sonnet-4-5-20250929-v1:0",
+        temperature=0.1,
+        streaming=True
+    )
+
+    memory_id = os.environ.get("MEMORY_ID")
+    if not memory_id:
+        raise ValueError("MEMORY_ID environment variable is required")
+
+    checkpointer = AgentCoreMemorySaver(
+        memory_id=memory_id,
+        region_name=os.environ.get("AWS_DEFAULT_REGION", "us-east-1")
+    )
+
+    mcp_client = await create_gateway_mcp_client()
+    tools = await mcp_client.get_tools()
+    logger.info("[AGUI-LG] Loaded %d tools from Gateway", len(tools))
+
+    # Code Interpreter
+    region = os.environ.get("AWS_DEFAULT_REGION", "us-east-1")
+    try:
+        from langgraph_code_interpreter import LangGraphCodeInterpreterTools
+        code_tools = LangGraphCodeInterpreterTools(region)
+        tools.append(code_tools.execute_python_securely)
+        logger.info("[AGUI-LG] Code Interpreter loaded")
+    except Exception as e:
+        logger.warning("[AGUI-LG] Code Interpreter not available: %s", e)
+
+    graph = create_react_agent(
+        model=bedrock_model,
+        tools=tools,
+        checkpointer=checkpointer,
+        prompt=system_prompt
+    )
+
+    return PatchedLangGraphAgent(
+        name="agui_langgraph_agent",
+        graph=graph,
+        description="AG-UI LangGraph agent with Gateway MCP tools and Memory",
+        config={"configurable": {"actor_id": user_id}},
+    )
+
+
+# --- Create app and register endpoint ---
+
+app = FastAPI(title="AG-UI LangGraph Agent")
+
+
+@app.post("/invocations")
+async def invocations(input_data: RunAgentInput, request: Request):
+    try:
+        setup_agentcore_context(request)
+        user_id = extract_user_id_from_request(request)
+        agent = await create_agent(user_id)
+
+        encoder = EventEncoder(accept=request.headers.get("accept"))
+
+        async def event_generator():
+            async for event in agent.run(input_data):
+                yield encoder.encode(event)
+
+        return StreamingResponse(event_generator(), media_type=encoder.get_content_type())
+    except Exception:
+        logger.exception("[AGUI-LG] /invocations failed")
+        raise
+
+
+@app.get("/ping")
+def ping():
+    return {"status": "Healthy"}
+
+
+if __name__ == "__main__":
+    import uvicorn
+    port = int(os.getenv("PORT", "8080"))
+    uvicorn.run("langgraph_agent:app", host="0.0.0.0", port=port, reload=True)