agent.cpp vs harness-sdk
Local C++ agents compared with Python and TypeScript agent tooling
agent.cpp builds local AI agents in C++ using llama.cpp and GGUF models. harness-sdk provides Python and TypeScript harnesses and SDKs, with support for multiple model providers and options ranging from ready-made defaults to custom agent loops.
agent.cpp: Build Local AI Agents in C++
agent.cpp is a C++ library for building agents that run small language models locally through llama.cpp. It provides an agent loop, tools, callbacks, and support for GGUF models, grammar constraints, and LoRA adapters.
harness-sdk: Build and Run AI Agents in Python and TypeScript
Strands Agents provides Python and TypeScript tools for building AI agents, from a ready-made harness to a customizable agent SDK. It suits teams that want model flexibility and control over agent execution without a hosted control plane.
| agent.cpp | harness-sdk | |
|---|---|---|
| Language | C++ | Python |
| License | MIT | Apache-2.0 |
| Stars | 210 | 8.6k |
| Forks | 31 | 1.3k |
| Last analyzed | Oct 3, 2026 | Oct 3, 2026 |
Key differences
- agent.cpp is a C++ library focused on local inference through llama.cpp; harness-sdk is a Python and TypeScript monorepo with harnesses and lower-level SDKs.
- agent.cpp uses GGUF models and supports GBNF grammar constraints and LoRA adapters; harness-sdk documents providers including Amazon Bedrock, Anthropic, OpenAI, and Gemini.
- agent.cpp centers on an agent loop, tools, and lifecycle callbacks; harness-sdk also offers configurable harness defaults, execution limits, sessions, streaming, hooks, tracing, and evaluation support.
- agent.cpp is licensed under MIT, while harness-sdk is licensed under Apache-2.0.
- The listed project sizes differ: agent.cpp has 210 stars and 31 forks, while harness-sdk has 8.6k stars and 1.3k forks.
Choose agent.cpp if you…
- need to run GGUF models locally through llama.cpp in a C++ application.
- want to customize tool execution or agent lifecycle behavior with callbacks.
- need grammar constraints or LoRA adapter support for a local agent.
Choose harness-sdk if you…
- want a ready-made Python or TypeScript harness with configurable defaults.
- need to choose among documented model providers or connect tools through MCP.
- want execution controls such as turn limits, token budgets, cancellation, or tracing.
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.