feat(llms): add Atlas Cloud as an OpenAI-compatible LLM backend

[lucaszhu-hue]

What

Adds Atlas Cloud as a first-class atlascloud LLM backend, alongside the existing openai, qwen, deepseek, and minimax providers.

Atlas Cloud exposes an OpenAI-compatible Chat Completions API, so this follows the exact same pattern already used for DeepSeek / Qwen / MiniMax:

• AtlasCloudLLMConfig — subclass of OpenAILLMConfig, defaulting api_base to https://api.atlascloud.ai/v1
• AtlasCloudLLM — subclass of OpenAILLM
• registered as "atlascloud" in both LLMConfigFactory and LLMFactory
• documented in the EN/CN model_backend guides

Why

It lets MemOS users point the existing LLM machinery at Atlas Cloud's hosted open models (DeepSeek, Qwen, Kimi, GLM, Llama, etc.) with a one-line backend= swap, no code changes elsewhere.

Usage

from memos.configs.llm import LLMConfigFactory
from memos.llms.factory import LLMFactory

cfg = LLMConfigFactory.model_validate({
    "backend": "atlascloud",
    "config": {
        "model_name_or_path": "deepseek-ai/DeepSeek-V3.1",
        "api_key": "<YOUR_ATLASCLOUD_API_KEY>",  # or read from env, e.g. os.environ["ATLASCLOUD_API_KEY"]
    },
})
llm = LLMFactory.from_config(cfg)
print(llm.generate([{"role": "user", "content": "Hello!"}]))

api_base defaults to https://api.atlascloud.ai/v1 and can be overridden like any other OpenAI-compatible backend.

Notes on the API key

The API key is passed through config exactly like the other OpenAI-compatible backends — nothing is hardcoded. Users supply their own key (commonly via the ATLASCLOUD_API_KEY environment variable).

Verification

• python -m py_compile passes on all changed files.
• Imported the factories in isolation and confirmed: atlascloud is registered in both LLMConfigFactory and LLMFactory, LLMConfigFactory.model_validate(...) produces an AtlasCloudLLMConfig with the correct default api_base, and AtlasCloudLLM is a subclass of OpenAILLM.

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Happy to adjust naming/docs to match maintainer preferences. For any questions about the Atlas Cloud API you can also reach us at marketing@atlascloud.ai.