Tool Executors

Tool executors allow users to customize the execution strategy of tools executed by the agent (e.g., concurrent vs sequential). Currently, Strands is packaged with 2 executors.

Concurrent Executor

Use ConcurrentToolExecutor (the default) to execute tools concurrently:

from strands import Agent
from strands.tools.executors import ConcurrentToolExecutor

agent = Agent(
    tool_executor=ConcurrentToolExecutor(),
    tools=[weather_tool, time_tool]
)
# or simply Agent(tools=[weather_tool, time_tool])

agent("What is the weather and time in New York?")

Assuming the model returns weather_tool and time_tool use requests, the ConcurrentToolExecutor will execute both concurrently.

Sequential Behavior

On certain prompts, the model may decide to return one tool use request at a time. Under these circumstances, the tools will execute sequentially. Concurrency is only achieved if the model returns multiple tool use requests in a single response. Certain models however offer additional abilities to coerce a desired behavior. For example, Anthropic exposes an explicit parallel tool use setting (docs).

Sequential Executor

Use SequentialToolExecutor to execute tools sequentially:

from strands import Agent
from strands.tools.executors import SequentialToolExecutor

agent = Agent(
    tool_executor=SequentialToolExecutor(),
    tools=[screenshot_tool, email_tool]
)

agent("Please take a screenshot and then email the screenshot to my friend")

Assuming the model returns screenshot_tool and email_tool use requests, the SequentialToolExecutor will execute both sequentially in the order given.

Custom Executor

Custom tool executors are not currently supported but are planned for a future release. You can track progress on this feature at GitHub Issue #762.