Agent TARSvsharness9
Generated from the two spec rows. Green marks the better value where a spec has a clear direction. Everything else is just different.
Agent TARS
ByteDance · Agent harness
OSSMCP
Panel
5.85 spec wins
- Reliability
- 5.5
- Usefulness
- 6.2
- Cost
- 6.8
- Longevity
- 4.8
“Its own showcase hands it a $5,000 budget and a Ritz-Carlton booking, which is one way to find out whether an agent stops.”
harness9
ZhangShenao · Agent harness
OSS
Panel
5.73 spec wins
- Reliability
- 5.5
- Usefulness
- 5.3
- Cost
- 7.2
- Longevity
- 4.7
“It positions itself between bloated frameworks and thin demos, which is the software equivalent of a dating profile that says normal.”
Spec by spec
| Spec | Agent TARS | harness9 |
|---|---|---|
| Architecture | ||
| Category | Agent harness | Agent harness |
| Runs | local | local |
| Platforms | macos, windows | macos, linux |
| Context window | not documented | not documented |
| Protocols | ||
| MCP client | Yes | No |
| MCP server | No | No |
| Capabilities | ||
| Runs terminal commands | Yes | Yes |
| Multi-file edits | No | Yes |
| Git operations | No | Yes |
| Browser control | Yes | No |
| Sandboxed execution | No | Yes |
| Multi-agent orchestration | No | No |
| Headless / CI mode | Yes | No |
| Models | ||
| Backbone | Claude, Doubao, Seed-VL, UI-TARS | OpenAI, Anthropic, OpenRouter |
| Bring your own model | Yes | Yes |
| Local models | Yes | No |
| Cost | ||
| Pricing model | byok | byok |
| Starts at | $0/mo | $0/mo |
| Free tier | Yes | Yes |
| Bring your own key | Yes | Yes |
| Openness | ||
| Open source | Yes | Yes |
| License | Apache-2.0 | MIT |
| GitHub stars | 39,180 | 141 |
Which one would each critic pick
| Critic | Agent TARS | harness9 | Pick |
|---|---|---|---|
| El Juez | — | — | not enough reviews |
| El Amigo | 6.3 | 6.3 | no preference |
| El Crítico | 5.5 | 5.8 | harness9 — Tools run inside a container, but the shell escape prefix and the stored state do not, so the isolation covers the tidy half of what an agent does. |
| El Profesor | 6.0 | 5.5 | Agent TARS — The kernel is MCP, context is a protocol-driven event stream, and grounding is visual, DOM or hybrid; the model is the UI-TARS work in arXiv 2501.12326, whose numbers the README does not restate. |
| La Inversora | 5.3 | 4.5 | Agent TARS — A ByteDance research project: no pricing, free remote operators, weights on Hugging Face and ModelScope, and the business is Doubao tokens on Volcengine; strategic projects get shelved, not sold. |
| La Jefa | 5.0 | 5.5 | harness9 — Every plan, tool result and record stays on the developer's own machine, which answers the data residency question and creates the discovery problem. |
| El Hacker | 7.0 | 6.5 | Agent TARS — Apache-2.0, --provider --model --apiKey on the command line, MCP servers mounted as tools, a UI TARS SDK for building my own GUI agent, and Midscene if I only want the browser half. |
Picks are derived from each critic's own scores. Humans vote on matchups on the duels page.