Agent ZerovsHarnessX
Generated from the two spec rows. Green marks the better value where a spec has a clear direction. Everything else is just different.
Agent Zero
Agent Zero, s.r.o. · Agent framework
OSSMCP
Panel
6.36 spec wins
- Reliability
- 5.5
- Usefulness
- 6.7
- Cost
- 7.0
- Longevity
- 6.0
“It can cowork with you on LibreOffice documents, which is the most 2003 sentence ever written about an autonomous agent.”
HarnessX
Darwin Agent · Agent framework
OSS
Panel
6.31 spec wins
- Reliability
- 5.8
- Usefulness
- 6.5
- Cost
- 7.5
- Longevity
- 5.5
“It connects to Feishu, Telegram, Slack, Discord and DingTalk, so the agent has wider messaging coverage than most of its users.”
Spec by spec
| Spec | Agent Zero | HarnessX |
|---|---|---|
| Architecture | ||
| Category | Agent framework | Agent framework |
| Runs | local, sandbox | local, sandbox |
| Platforms | macos, linux, windows | macos, linux |
| Context window | not documented | not documented |
| Protocols | ||
| MCP client | Yes | No |
| MCP server | Yes | No |
| Capabilities | ||
| Runs terminal commands | Yes | Yes |
| Multi-file edits | Yes | Yes |
| Git operations | Yes | No |
| Browser control | Yes | No |
| Sandboxed execution | Yes | YesThe sandbox dimension ships local, Docker and E2B backends. |
| Multi-agent orchestration | Yes | YesA meta-agent and an observer harness run alongside the main agent in the harness evolution loop. |
| Headless / CI mode | No | Yes"hx -p" runs a single prompt non-interactively and exits. |
| Models | ||
| Backbone | any | Anthropic, any configured provider |
| Bring your own model | Yes | Yes |
| Local models | Yes | No |
| Cost | ||
| Pricing model | byok | byok |
| Starts at | n/a | $0/mo |
| Free tier | Yes | Yes |
| Bring your own key | Yes | Yes |
| Openness | ||
| Open source | Yes | Yes |
| License | MIT | MIT |
| GitHub stars | 19,357 | 483 |
Which one would each critic pick
| Critic | Agent Zero | HarnessX | Pick |
|---|---|---|---|
| El Juez | — | — | not enough reviews |
| El Amigo | 6.8 | 6.5 | Agent Zero — Pick Agent Zero when the job is driving real desktop applications; pick OpenHands when the job is a git repository and a test suite. |
| El Crítico | 6.3 | 5.5 | Agent Zero — Every prompt, tool and config file is editable by design, and the agent has read and write access to the same files, so the rules it follows are inside its own blast radius. |
| El Profesor | 6.5 | 7.0 | HarnessX — The composition is the argument: model routing on one side, a pipeline of behaviours on the other, joined by an operator rather than by inheritance. |
| La Inversora | 5.3 | 6.0 | HarnessX — 454 stars and a research agenda dressed as a framework: interesting people, no revenue mechanism, and an idea larger than any product around it. |
| La Jefa | 5.0 | 5.8 | HarnessX — It runs one prompt non-interactively and exits, which makes it schedulable; the hosted sandbox backend makes it a vendor review before that helps me. |
| El Hacker | 8.0 | 7.3 | Agent Zero — MIT, one docker run with an a0_usr volume, LiteLLM in front of every provider, Ollama for local weights, and it works as an MCP client and an MCP server. |
Picks are derived from each critic's own scores. Humans vote on matchups on the duels page.