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  1. v1.25.0

    Feb 5, 2026
    GitHub release PyPI 1.25.0

    Major Features

    A2AAgent: First-Class Client for Remote A2A Agents - PR#1441

    The new A2AAgent class makes it simple to connect to and invoke remote agents that implement the Agent-to-Agent (A2A) protocol. A2AAgent implements the AgentBase protocol, so it can be called synchronously, asynchronously, or used in streaming mode just like a local Agent. It automatically discovers the remote agent’s card to populate its name and description, and manages HTTP client lifecycle for you.

    from strands.agent.a2a_agent import A2AAgent
    

    # Connect to a remote A2A agent
    a2a_agent = A2AAgent(endpoint="http://localhost:9000")
    

    # Invoke it like any other agent
    result = a2a_agent("Show me 10 ^ 6")
    print(result.message)
    

    # Or stream events asynchronously
    async for event in a2a_agent.stream_async("Summarize this report"):
        if event.get("type") == "a2a_stream":
            print(f"A2A event: {event['event']}")
        elif "result" in event:
            print(f"Final: {event['result'].message}")

    A2AAgent Support in Graph Workflows - PR#1615

    Graph nodes now accept any AgentBase implementation as an executor, not just the concrete Agent class. This means A2AAgent instances and other custom AgentBase implementations can participate in graph-based multi-agent workflows alongside local agents. The Agent class also now explicitly extends AgentBase for compile-time protocol verification.

    from strands import Agent
    from strands.agent.a2a_agent import A2AAgent
    from strands.multiagent.graph import GraphBuilder
    

    local_agent = Agent(name="summarizer", system_prompt="Summarize input concisely.")
    remote_agent = A2AAgent(endpoint="http://remote-agent:9000")
    

    builder = GraphBuilder()
    builder.add_node(remote_agent, "research")
    builder.add_node(local_agent, "summarize")
    builder.add_edge("research", "summarize")
    graph = builder.build()
    

    result = graph("Analyze recent AI trends")

    Interrupt Support for MultiAgent Graph Nodes - PR#1606

    Interrupts now propagate correctly through nested multi-agent graph nodes. When an agent inside a nested Graph, Swarm, or any custom MultiAgentBase node raises an interrupt, the outer graph pauses execution and surfaces the interrupt to the caller. After the caller provides a response, the outer graph resumes execution from where it left off. This builds on the interrupt support for single-agent graph nodes added in v1.24.0.

    from strands import Agent, tool
    from strands.interrupt import Interrupt
    from strands.multiagent import GraphBuilder, Status
    from strands.types.tools import ToolContext
    

    @tool(context=True)
    def approval_tool(tool_context: ToolContext) -> str:
        return tool_context.interrupt("approval", reason="Needs human approval")
    

    agent = Agent(name="reviewer", tools=[approval_tool])
    

    inner_graph = GraphBuilder()
    inner_graph.add_node(agent, "reviewer")
    outer_graph = GraphBuilder()
    outer_graph.add_node(inner_graph.build(), "review_pipeline")
    

    graph = outer_graph.build()
    result = graph("Review this document")
    

    while result.status == Status.INTERRUPTED:
        responses = [
            {"interruptResponse": {"interruptId": i.id, "response": "Approved"}}
            for i in result.interrupts
        ]
        result = graph(responses)

    S3 Location Support for Documents, Images, and Videos - PR#1572

    Media content types now support S3 locations as a source, allowing you to reference documents, images, and videos stored in Amazon S3 directly without base64 encoding. The new S3Location type includes a required uri field and an optional bucketOwner field for cross-account access. On Bedrock, S3 locations are passed through to the API natively.

    from strands import Agent
    

    agent = Agent()
    

    response = agent([{
        "role": "user",
        "content": [
            {"text": "Summarize this document:"},
            {
                "document": {
                    "format": "pdf",
                    "name": "report",
                    "source": {
                        "location": {
                            "type": "s3",
                            "uri": "s3://my-bucket/documents/report.pdf",
                            "bucketOwner": "123456789012"  # optional, for cross-account
                        }
                    }
                }
            }
        ]
    }])

    Configurable Structured Output Prompt - PR#1627

    The prompt message the agent uses to request structured output formatting is now configurable via the structured_output_prompt parameter. Previously, the hardcoded message "You must format the previous response as structured output." could trigger Bedrock Guardrails prompt-attack filters. You can now customize this message at the agent level or per invocation to work around guardrail rules or to better suit your use case.

    from strands import Agent
    from pydantic import BaseModel
    

    class UserInfo(BaseModel):
        name: str
        age: int
    

    # Custom prompt avoids triggering Bedrock Guardrails prompt attack filter
    agent = Agent(
        structured_output_model=UserInfo,
        structured_output_prompt="Please use the output tool now."
    )
    

    # Or override per invocation
    result = agent(
        "Extract user info from: John is 30 years old",
        structured_output_prompt="Format the response using the output tool."
    )

    Major Bug Fixes

    • Nullable Semantics Preserved for Required Union[T, None] Tool Parameters - PR#1584 When a @tool parameter was typed as T | None without a default value, the schema cleaning logic was stripping null from the anyOf array, making the field required with no way to express null. This caused LLMs to fall back to passing "null" as a string. The anyOf simplification is now skipped for fields in the required array, preserving proper nullable semantics.

    • LedgerProvider Now Handles Parallel Tool Calls Correctly - PR#1559 When agents proposed multiple tool calls in a single model response, the ledger provider only updated the last tool in the batch (ledger['tool_calls'][-1]), leaving earlier pending tools without proper status updates. The provider now correctly tracks and updates each individual tool call.

    • Context Overflow Detection for OpenAI-Compatible Bedrock Endpoints - PR#1529 OpenAI-compatible endpoints that wrap Bedrock models (e.g., Databricks Model Serving) return Bedrock-style error messages like "Input is too long for requested model" as APIError instead of BadRequestError with code context_length_exceeded. These errors are now detected and converted to ContextWindowOverflowException, allowing conversation managers like SummarizingConversationManager to trigger properly.

    • retry_strategy=None Now Disables Retries - PR#1630 Passing retry_strategy=None to the Agent constructor previously applied the default retry strategy instead of disabling retries. Now None explicitly disables all SDK retries (equivalent to ModelRetryStrategy(max_attempts=1)), while omitting the parameter entirely still applies the default strategy. Note: This is a minor breaking change in behavior for code that explicitly passed None.

    • A2A Server Agent Card URL Updated on Host/Port Override - PR#1626 When overriding host and port in A2AServer.serve(), the agent card at /.well-known/agent-card.json still returned the original URL from constructor defaults, causing A2A clients to connect to the wrong address. The server now updates the agent card URL to match the overridden host/port, unless an explicit http_url was provided in the constructor.

    Minor Changes

    • Increase pytest timeout to 45 seconds - PR#1586
    • Publish integ test results to CloudWatch - PR#1587
    • Clone main metrics upload script for integ tests - PR#1600
    • Skip S3 location for non-Bedrock model providers - PR#1602
    • Add conditional execution for finalize step - PR#1605
    • Fix various test warnings - PR#1613
    • Fix Bedrock file warnings - PR#1603
    • Increase test timeout - PR#1623
    • Fix OpenAI test - PR#1624
    • Remove broken MCP transport timeout test - PR#1635
    • Bump actions/setup-python from 4 to 6 - PR#1548
    • Bump aws-actions/configure-aws-credentials from 4 to 5 - PR#1547
    • Bump actions/download-artifact from 4 to 7 - PR#1609
    • Bump actions/upload-artifact from 4 to 6 - PR#1608

    ✦ Features 3

    ⊘ Fixes 5

    ⋯ Other 16