The 32 harnesses we studied

Each one was read at a pinned version, in its code, or in its official docs when the code is closed. Independent analysis, not affiliated with these projects.

Same core, five harnesses

Each harness wraps a model in its own brackets: its own loop, tools and memory. Each colour is one harness. Watch one core dock into each in turn.

piOpen source · TypeScript
Claude CodeClosed, studied from outside
codexOpen source · Rust
opencodeOpen source · TypeScript
hermes-agentOpen source · Python

adk-pythonOpen source · Python
Agent-SPublic code, licence not stated · Python
amplioOpen source
browser-useOpen source · Python
Claude CodeClosed, studied from outside
clineOpen source · TypeScript
codexOpen source · Rust
cuaPublic code, licence not stated · Python
CursorClosed, studied from outside
deepagentsOpen source · Python
deepseek-harnessOpen source · TypeScript
deer-flowOpen source · Python
Devin (formerly Windsurf)Closed, studied from outside
gemini-cliOpen source · TypeScript
gooseOpen source · Rust
gpt-researcherOpen source · Python
hermes-agentOpen source · Python
langchainOpen source · Python
langgraphOpen source · Python
mem0Public code, licence not stated · Python
onyxPublic code, licence not stated · Python
open_deep_researchOpen source · Python
openai-agents-pythonOpen source · Python
openclawOpen source · TypeScript
opencodeOpen source · TypeScript
OpenHands appOpen source · TypeScript
OpenHands SDKOpen source · Python
piOpen source · TypeScript
stagehandOpen source · TypeScript
stormOpen source · Python
UI-TARS-desktopOpen source · TypeScript
VaneOpen source · TypeScript