harnessrouter vs agent-service-toolkit
Agent harness infrastructure compared with a LangGraph toolkit
harnessrouter provides a self-hosted API for running multiple agent harnesses through a shared interface. agent-service-toolkit brings LangGraph agents, a FastAPI service, a reusable client, and a Streamlit chat UI together; it is a starter foundation for building agent applications.
harnessrouter: Unify Agent Harnesses Behind One API
HarnessRouter is a self-hosted Python service built around the Unified Harness Protocol (UHP), with an OpenAI Responses-compatible API for agent harnesses such as Codex and Claude Code. It gives product teams one interface for sessions, streaming, files, cancellation, and failures.
agent-service-toolkit: Build and Serve LangGraph Agents
A Python starter toolkit that connects LangGraph agents to a FastAPI service, reusable client, and Streamlit chat interface. It suits developers who want an end-to-end foundation for building, testing, and customizing agent applications.
| harnessrouter | agent-service-toolkit | |
|---|---|---|
| Language | Python | Python |
| License | Apache-2.0 | MIT |
| Stars | 3.1k | 4.5k |
| Forks | 345 | 789 |
| Last analyzed | Oct 20, 2026 | Oct 3, 2026 |
Key differences
- harnessrouter focuses on unifying existing harnesses such as Codex and Claude Code, while agent-service-toolkit focuses on building and serving LangGraph agents.
- harnessrouter implements the Unified Harness Protocol and offers an OpenAI Responses-compatible API; agent-service-toolkit exposes FastAPI endpoints and supports the AG-UI protocol for compatible frontends.
- harnessrouter is Apache-2.0 licensed, while agent-service-toolkit is MIT licensed.
- harnessrouter's Docker deployment provides persistent storage and isolated workspaces with operating-system users; agent-service-toolkit's Docker Compose setup runs the service, interface, and PostgreSQL database.
- harnessrouter is aimed at teams integrating multiple harnesses and managing agent tasks on their own infrastructure; agent-service-toolkit is aimed at developers building or learning to build LangGraph applications.
Choose harnessrouter if you…
- need one API for multiple agent harnesses and shared session handling.
- want to run harness-backed tasks on your own infrastructure.
- need UHP schemas or a conformance suite for protocol work.
Choose agent-service-toolkit if you…
- want a starting point for serving LangGraph agents through FastAPI.
- need a ready-made Streamlit chat interface, reusable client, and streaming support.
- want to adapt examples for human-in-the-loop control, memory, or RAG.
Compare the numbers side by side, or add more projects
This comparison is generated with AI from the OSRepos analyses of both projects. Always check each project's repository and documentation before choosing.