strands-agents/harness-sdk

Strands Agents A model-driven approach to building AI agents in just a few lines of code. Documentation ◆ Samples ◆ Tools ◆ MCP Server Strands Agents is an open-source SDK for building and running AI agents in Python and TypeScript. Choose Strands when you would otherwise write your own agent loop: it runs in your process with no hosted control plane, and it covers the jobs a hand-rolled loop grows into. In one SDK you get lifecycle controls (turn limits, token budgets, cancellation, stop reasons), tools and structured output , MCP , multi-agent patterns , memory and sessions , model portability , streaming , guardrails , tracing , and evals . This monorepo contains the Python SDK, TypeScript SDK, documentation site, and supporting packages: Directory Description strands-py/ Python SDK: agent loop, model providers, tools ( PyPI · releases ) strands-ts/ TypeScript SDK: agent loop, model providers, tools ( npm · releases ) site/ Source for the strandsagents.com documentation site (Astro/Starlight) team/ Governance and cross-SDK process docs (tenets, decisions, PR & compatibility guidelines, and designs/ proposals) Why Strands Build an agent harness. Control it end-to-end. Build your way. Any model, any cloud. Context management, execution limits, and observability built in before you write a line of config. Swap backends when you scale; your code stays the same. Model agnostic. First-class support for Amazon Bedrock, Anthropic, OpenAI, and Gemini, plus many more providers and custom ones. Stay in control. The agent loop traces every decision by default. Hooks let you intercept any step to log it, validate it, or redirect it. Deliver outcomes that work. Guardrails catch mistakes before they run. Steering handlers let agents correct themselves instead of failing silently. MCP, streaming, multi-agent patterns, and structured output are all built in. Quick Start Both SDKs default to the Amazon Bedrock model provider, so you'll need AWS credentials configured and model access enabled for Claude Sonnet. The Quickstart Guide covers configuring other providers (Anthropic, OpenAI, Gemini, Ollama, and more). Python Requires Python 3.10+: pip install strands-agents strands-agents-tools from strands import Agent from strands_tools import calculator agent = Agent ( tools = [ calculator ]) agent ( "What is the square root of 1764" ) The Python SDK README covers tools, model providers, MCP, and bidirectional streaming. TypeScript Requires Node.js 22+: npm install @strands-agents/sdk import { Agent } from '@strands-agents/sdk' const agent = new Agent ( ) const result = await agent . invoke ( 'What is the square root of 1764?' ) console . log ( result ) More in the TypeScript SDK README , including Zod-typed tools, structured output, and multi-agent patterns. Documentation For detailed guidance & examples, explore our documentation: User Guide Quick Start Guide Agent Loop Examples API Reference: Python · TypeScript Production & Deployment Guide The docs themselves live in this monorepo under site/ , and doc PRs are welcome alongside code changes. Development Git operations (commits, branches, PRs) are done from the repo root. Each package has its own toolchain: Python SDK ( strands-py/ ): cd strands-py pip install hatch hatch test # run unit tests hatch fmt # format & lint TypeScript SDK ( strands-ts/ ): npm ci # install from repo root npm run build # build npm test # run unit tests Documentation site ( site/ ): cd site npm install npm run dev # local dev server at http://localhost:4321/ Contributing ❤️ We welcome contributions! See our Contributing Guide for details on: Reporting bugs & features Development setup Contributing via Pull Requests Code of Conduct Reporting of security issues Stay in touch with the team Come meet the Strands team and other users on Discord License This project is licensed under the Apache License 2.0 - see the LICENSE.APACHE file for details. Security See CONTRIBUTING for more information.