The gist

Strands Agents Harness SDK is an open-source framework for building and running AI agents. Provided as both Python and TypeScript SDKs, it offers a model-driven approach to creating everything from simple chatbots to complex autonomous workflows. The framework is designed to give developers end-to-end control over the agent execution loop, with built-in observability, context management, and support for multiple large language model providers.

What it does

Build and control AI agent harnesses with end-to-end observability.
Connect to major LLM providers including Amazon Bedrock, Anthropic, OpenAI, and Gemini.
Trace and intercept every step of the agent loop with custom hooks for logging or validation.
Implement guardrails and steering handlers to catch errors and enable self-correction.
Develop agents using feature-rich SDKs for both Python and TypeScript.
Utilize built-in support for multi-agent patterns, bidirectional streaming, and structured output.

How it works

Developers install the SDK as a package in their Python or TypeScript project. They write code to instantiate an agent, provide it with tools, and connect it to an LLM provider like OpenAI or Amazon Bedrock. The SDK handles the agent's decision-making loop, tracing each step for observability. It's an open-source library that outputs the agent's final response or structured data.

Best for

This SDK is best for developers building custom AI agents who need fine-grained control over the execution loop, from local development prototypes to scalable production systems.

Watch out for

The default configuration uses Amazon Bedrock, requiring users to have AWS credentials and model access configured before starting, which may be a hurdle for beginners.