Strands' TypeScript SDK: agents by schema, now archived

What it does The SDK provides a TypeScript and JavaScript framework for building AI agents around a tight interaction loop between users, models, and tools. It bundles support for Amazon Bedrock and OpenAI into an Agent class that handles tool calling, structured output validation, and conversation history. The library also runs in browsers and offers multi-agent orchestration through deterministic graphs and dynamic swarms.

The interesting bit Nearly every boundary is guarded by Zod: tool inputs, structured outputs, and automatic retries when the LLM returns malformed JSON. That level of schema discipline is rare in the JavaScript AI tooling space. The orchestration patterns are also cleanly split—Graph for fixed execution pipelines and Swarm for model-driven handoffs—so you choose between rigid control and emergent routing.

Key highlights

• First-class MCP client support for connecting to external tool servers
• Vended tools for notebooks, file editing, and HTTP requests included out of the box
• Streaming responses and lifecycle hooks for monitoring and customization
• Deterministic Graph and dynamic Swarm patterns for multi-agent workflows
• Repository archived; source code and development moved to strands-agents/harness-sdk

Caveats

• This repository is archived; all new issues and pull requests must go to the harness-sdk monorepo
• The default Bedrock provider requires AWS credentials and enabled model access for Claude Sonnet
• The OpenAI quickstart example references gpt-5.4, which appears to be a typo

Verdict TypeScript developers who want Zod-shaped guardrails around LLM agents should track the project to its new monorepo. If you need a Python-first framework or a standalone, actively maintained repo, this exact repository is a historical snapshot.