Strands Agents

What is supported

strands-agents 1.0 and later. Onecortex recognises a Strands Agent and streams it with stream_async.

A complete agent

agent.yml

apiVersion: v1
runtime: python3.12
entrypoint: agent.py:agent
dependencies: requirements.txt

requirements.txt

strands-agents[openai]>=1.0

agent.py

import os

from strands import Agent, tool
from strands.models.openai import OpenAIModel


@tool
def word_count(text: str) -> int:
    """Counts the words in a piece of text."""
    return len(text.split())


# OPENAI_API_KEY is a secret you add on the agent's Config tab.
model = OpenAIModel(client_args={"api_key": os.environ["OPENAI_API_KEY"]}, model_id="gpt-5")
agent = Agent(model=model, tools=[word_count])

Add OPENAI_API_KEY as a secret on the agent’s Config tab, then deploy. Any model works: this one is an example. See Configuration and secrets.

A complete Strands Agents example

weather-planner: A day planner that checks a forecast tool first, on the oldest supported release. It runs with no model key.

The prompt and the reply

The prompt is the agent’s input. The reply is its streamed text.

Events it reports

Events	From
`text`	The streamed text
`tool_call_start`, `tool_call_args`, `tool_call_end`	Each tool call as the model forms it
`tool_result`	Each tool’s result, with `isError` when it failed
`done` or `error`	The end of the run: always exactly one

See Streaming and events.

The caller’s fields

In the invocation state, as invocation_state["onecortex"], which Strands hands to tools that ask for their context:

from strands import ToolContext, tool


@tool(context=True)
def get_forecast(city: str, tool_context: ToolContext) -> str:
    params = tool_context.invocation_state["onecortex"]["params"]
    units = params.get("units", "metric")
    ...

Sessions: Strands’ own session managers are not connected. The same sessionId reaches the same running instance, where the agent object keeps its conversation in memory. See Sessions.

Known limits

Choose a model explicitly: an agent created without model= uses Strands’ default provider, which needs credentials you would have to supply.

Troubleshooting

You see	Do this
The build’s smoke test fails with a credentials error from the model	Pass `model=` explicitly, and add its key as a secret.

Get started

Build your agent

Frameworks

Deploy

Call your agent

Observe

Production

Organizations

Resources

What is supported

A complete agent

A complete Strands Agents example

The prompt and the reply

Events it reports

The caller’s fields

Known limits

Troubleshooting

​What is supported

​A complete agent

A complete Strands Agents example

​The prompt and the reply

​Events it reports

​The caller’s fields

​Known limits

​Troubleshooting

What is supported

A complete agent

The prompt and the reply

Events it reports

The caller’s fields

Known limits

Troubleshooting