ArborvsContrabass
Generated from the two spec rows. Green marks the better value where a spec has a clear direction. Everything else is just different.
Arbor
penso · Agent harness
OSSMCP
Panel
7.23 spec wins
- Reliability
- 7.0
- Usefulness
- 7.0
- Cost
- 8.7
- Longevity
- 6.0
“It manages your repositories, your worktrees, your terminals and your processes, so the only unmanaged thing left in the room is you.”
Contrabass
junhoyeo · Agent harness
OSSMCP
Panel
7.11 spec wins
- Reliability
- 6.8
- Usefulness
- 7.3
- Cost
- 8.2
- Longevity
- 6.0
“Every issue gets a worktree under workspaces/ named after the ticket, so your filesystem is now a faithful copy of your backlog.”
Spec by spec
| Spec | Arbor | Contrabass |
|---|---|---|
| Architecture | ||
| Category | Agent harness | Agent harness |
| Runs | local | local |
| Platforms | macos, linux, windows, web | macos, linux |
| Context window | not documented | not documented |
| Protocols | ||
| MCP client | Yes | No |
| MCP server | Yes | Yes |
| Capabilities | ||
| Runs terminal commands | Yes | Yes |
| Multi-file edits | Yes | YesFiles are changed by the agent runner Contrabass launches in each issue's worktree. |
| Git operations | Yes | Yes |
| Browser control | No | No |
| Sandboxed execution | No | No |
| Multi-agent orchestration | Yes | Yes |
| Headless / CI mode | No | YesA --no-tui flag runs the orchestrator headless with events logged to stdout. |
| Models | ||
| Backbone | Claude Code, Codex, OpenCode | Codex app-server, OpenCode, oh-my-opencode, OMX, OMC |
| Bring your own model | Yes | Yes |
| Local models | YesOllama appears among the providers Arbor can be pointed at. | 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 | MIT | Apache-2.0 |
| GitHub stars | 831 | 223 |
Which one would each critic pick
| Critic | Arbor | Contrabass | Pick |
|---|---|---|---|
| El Juez | — | — | not enough reviews |
| El Amigo | 7.5 | 7.5 | no preference |
| El Crítico | 6.8 | 6.8 | no preference |
| El Profesor | 7.5 | 7.5 | no preference |
| La Inversora | 6.8 | 6.5 | Arbor — 809 stars, a personal namespace and a documentation site on GitHub Pages: nothing to fund, nothing to fail, and nobody to answer the phone. |
| La Jefa | 6.3 | 6.3 | no preference |
| El Hacker | 8.3 | 8.0 | Arbor — MIT, brew install, MCP consumed and served in both directions, and Ollama among the providers, so the model can be the one running on my box. |
Picks are derived from each critic's own scores. Humans vote on matchups on the duels page.