OpenChambervsTessera
Generated from the two spec rows. Green marks the better value where a spec has a clear direction. Everything else is just different.
OpenChamber
OpenChamber · Agent harness
OSS
Panel
6.32 spec wins
- Reliability
- 6.2
- Usefulness
- 6.5
- Cost
- 6.0
- Longevity
- 6.5
“Prompts can be scheduled daily, weekly or on a cron, so the agent can now disappoint you on a timetable.”
Tessera
Horang Labs · Agent harness
OSS
Panel
6.30 spec wins
- Reliability
- 5.8
- Usefulness
- 6.5
- Cost
- 6.8
- Longevity
- 5.8
“A paired phone continues the same sessions, so the agent can now wait for your approval while you are asleep.”
Spec by spec
| Spec | OpenChamber | Tessera |
|---|---|---|
| Architecture | ||
| Category | Agent harness | Agent harness |
| Runs | local | local |
| Platforms | macos, linux, windows, web | macos, linux, windows, web |
| Context window | not documented | not documented |
| Protocols | ||
| MCP client | No | No |
| MCP server | No | No |
| Capabilities | ||
| Runs terminal commands | YesCommand execution happens in the OpenCode agent OpenChamber launches; OpenChamber lets you reattach to a running terminal from any paired device. | Yes |
| Multi-file edits | Yes | YesFiles are changed by the Claude Code, Codex or OpenCode session Tessera runs in each worktree; Tessera adds its own file and diff editor on top. |
| Git operations | YesMulti-run can put each parallel session in its own git worktree, and GitHub sessions can update or merge a pull request from inside OpenChamber. | Yes |
| Browser control | YesPreview opens the running app beside the conversation, and the desktop build has a built-in browser that can send an element's screenshot, styles and console errors to the agent. | No |
| Sandboxed execution | No | No |
| Multi-agent orchestration | YesMulti-run gives one task to up to five models at once and Fusion merges the best parts of their results. | YesA lead agent can create worktrees and launch, read and prompt parallel worker sessions through the /tessera-cli command. |
| Headless / CI mode | No | No |
| Models | ||
| Backbone | OpenCode | Claude Code, Codex, OpenCode |
| Bring your own model | Yes | Yes |
| Local models | No | 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 | AGPL-3.0 |
| GitHub stars | 11,015 | 311 |
Which one would each critic pick
| Critic | OpenChamber | Tessera | Pick |
|---|---|---|---|
| El Juez | — | — | not enough reviews |
| El Amigo | 6.3 | 6.8 | Tessera — Pick Tessera if you want agent work to move through visible stages; pick a single session if a board with five columns would only be a board you stopped updating. |
| El Crítico | 5.5 | 5.3 | OpenChamber — Pointing at an element sends the running page's screenshot, styles and console errors to the agent, so whatever that page contains becomes agent input. |
| El Profesor | 6.8 | 6.5 | OpenChamber — A goal is checked after every turn and the loop continues until it is met, blocked, or a limit is reached, which is a stated termination condition. |
| La Inversora | 6.5 | 5.8 | OpenChamber — 9,556 stars and over twenty-three thousand editor installations from a repository that did not exist before September 2025, with nothing charged for any of it. |
| La Jefa | 6.0 | 5.8 | OpenChamber — Self-hosted with an encrypted relay paired by scanning a code, which answers where the data goes and opens the question of whose phone is holding it. |
| El Hacker | 6.8 | 7.5 | Tessera — Strong copyleft, which is the licence I want on something I depend on, and each backend takes a custom model identifier so I decide what is actually behind each session. |
Picks are derived from each critic's own scores. Humans vote on matchups on the duels page.