AtmospherevsStirrup
Generated from the two spec rows. Green marks the better value where a spec has a clear direction. Everything else is just different.
Atmosphere
Atmosphere · Agent framework
OSSMCP
Panel
6.93 spec wins
- Reliability
- 6.5
- Usefulness
- 6.7
- Cost
- 8.3
- Longevity
- 6.2
“One annotation gives you memory, plans, files and sub-agents, which is more than most annotations manage in a career.”
Stirrup
Artificial Analysis · Agent framework
OSSMCP
Panel
6.81 spec wins
- Reliability
- 6.7
- Usefulness
- 6.5
- Cost
- 8.2
- Longevity
- 6.0
“The Python framework has a TypeScript twin called StirrupJS, because no agent library is allowed to exist in only one language.”
Spec by spec
| Spec | Atmosphere | Stirrup |
|---|---|---|
| Architecture | ||
| Category | Agent framework | Agent framework |
| Runs | local, sandbox | local, sandbox |
| Platforms | macos, linux, windows | macos, linux, windows |
| Context window | not documented | not documented |
| Protocols | ||
| MCP client | Yes | Yes |
| MCP server | Yes | No |
| Capabilities | ||
| Runs terminal commands | YesCode execution goes through the atmosphere-sandbox SandboxProvider SPI, whose default implementation is DockerSandboxProvider. | Yes |
| Multi-file edits | YesAgents get six bounded, conversation-scoped filesystem tools (ls, read_file, write_file, edit_file, glob, grep) over a virtual filesystem. | Yes |
| Git operations | No | No |
| Browser control | NoBrowser automation and headless Chromium are explicitly listed as out of scope, to be supplied by your own stack. | YesA browser extra adds online search and web-page fetching, not general browser automation. |
| Sandboxed execution | Yes | YesCode execution runs locally, in Docker or in an E2B sandbox, selected through optional install extras. |
| Multi-agent orchestration | Yes | No |
| Headless / CI mode | No | No |
| Models | ||
| Backbone | OpenAI, Anthropic, Gemini, DashScope, Ollama, any OpenAI-compatible endpoint | any OpenAI-compatible API, LiteLLM, OpenRouter |
| Bring your own model | Yes | Yes |
| Local models | YesOllama and local OpenAI-compatible proxies are listed as supported model providers. | YesAny OpenAI-compatible base URL is supported, and LiteLLM adds routing to local runtimes. |
| 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 | 3,816 | 642 |
Which one would each critic pick
| Critic | Atmosphere | Stirrup | Pick |
|---|---|---|---|
| El Juez | — | — | not enough reviews |
| El Amigo | 6.8 | 7.3 | Stirrup — Pick it when you want an agent that stops and asks rather than guessing; pick a heavier framework if you want the workflow decided for you in advance. |
| El Crítico | 6.3 | 6.8 | Stirrup — Code execution runs locally by default, with Docker and E2B available through optional install extras, so the safe modes are the ones you have to remember to choose. |
| El Profesor | 7.5 | 6.5 | Atmosphere — Every agent gets long-term memory, a written plan and six bounded filesystem tools over a virtual filesystem, which makes capability explicit and finite rather than open. |
| La Inversora | 6.0 | 6.8 | Stirrup — Artificial Analysis sells independent model comparison, and this framework, at 578 stars, is a distribution asset for that business rather than a product with a price. |
| La Jefa | 7.3 | 5.8 | Atmosphere — Policy admission, human approval steps, cost ceilings and PII redaction all ship in the box, which is the list I normally have to build myself at sixty seats. |
| El Hacker | 7.8 | 8.0 | Stirrup — MIT on PyPI, an MCP client, and LiteLLM or any OpenAI-compatible base URL, so pointing it at the model server on my own network is a configuration line. |
Picks are derived from each critic's own scores. Humans vote on matchups on the duels page.