Deep Agents
Deep Agents is an open-source developer library and agent harness for building LLM-powered agents that can work through multi-step tasks. It provides an agent loop with built-in capabilities for planning, persistent memory, file-system interaction, and delegation to subagents, while allowing developers to connect model providers and tools. The library is intended for software developers and teams creating custom agent applications, including research, coding, and other workflows that require an agent to plan and act across several steps. Developers can extend its behavior with custom tools, middleware, and backends, and integrate it with LangGraph and LangSmith for orchestration, tracing, and deployment workflows. Deep Agents is a software development framework rather than a ready-made end-user agent application; users implement and run agents within their own applications and environments.
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eve
Eve is the framework for building agents, like Next.js for web apps, but for agents. It uses Markdown for instructions and skills, TypeScript for tools, and durable execution by default. An agent is a directory that defines instructions and skills in Markdown, tools in TypeScript, and then deploys. Eve compiles the directory, wires up durable workflows, and connects channels, giving developers a structured way to build production agents without gluing together point solutions. An instructions.md file can be a complete agent, while agent.ts lets teams choose a model or configure the runtime. Reusable skills are Markdown playbooks loaded when relevant, so the agent gets focused guidance without carrying everything in every prompt. Tools are added as TypeScript files, with the filename becoming the tool name, and no registration is required. Every agent includes an isolated sandbox and file tools, with support for custom sandbox setup.
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Flue
Flue is an open agent framework for building durable AI agents with a programmable TypeScript harness. Created by the team behind Astro, it uses a React-like hooks API to compose agent behavior, persistent state, lifecycle events, models, tools, sandboxes, subagents, skills, and MCP servers in code. Agents are stateful and addressable over HTTP, keep context across conversations and events, and can change capabilities as work progresses. Flue records every session in a durable stream, so accepted work survives crashes, restarts, and deploys; interrupted sessions resume automatically and clients reconnect without starting over. Developers can run agents locally, in CI, from their own backend, or orchestrate them with systems such as Cloudflare Workflows and Inngest. Secure sandboxes let agents run commands, edit files, and do real work, while tools connect them to APIs and data. Flue is powered by Pi and supports different LLM providers, allowing teams to choose the models they want.
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OpenHarness
OpenHarness is an open-source TypeScript SDK for developers building custom AI-agent applications, including coding agents, CLI tools, and web-based assistants. It provides stateless agent execution, explicit conversation-state handling, streaming events, composable middleware for retries, persistence and context compaction, hierarchical subagents, and permission-controlled tools. Developers can connect model providers through the Vercel AI SDK, add external capabilities through Model Context Protocol (MCP), and use filesystem or shell tools through configurable providers. The SDK also offers React hooks and Vue composables for streaming agent output into application interfaces. OpenHarness is installed as an npm package and is intended to be embedded in projects running on Node.js or edge runtimes; it is a developer library rather than a hosted end-user agent service.
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