hermes-impossibl

Impossibl as a first-class model provider for Hermes Agent.

Impossibl is an AI gateway: 100+ models from OpenAI, Anthropic, Google, xAI, DeepSeek, Moonshot, Z.ai, Qwen, MiniMax and more behind one OpenAI-compatible API and one key. This plugin registers the impossibl provider profile so hermes model, --provider impossibl, hermes doctor and the auxiliary-model defaults work out of the box. It ships as a standalone plugin because Hermes does not take third-party provider plugins in-tree.

Install

hermes plugins install impossiblco/hermes-impossibl --enable
echo 'IMPOSSIBL_API_KEY=<your key>' >> ~/.hermes/.env   # create one at https://impossibl.com
hermes model                                            # choose "Impossibl", then a model

Or set it directly in ~/.hermes/config.yaml:

model:
  provider: impossibl
  default: anthropic/claude-sonnet-5

Switch mid-session with /model impossibl:openai/gpt-5.5.

Model ids

Ids are <creator>/<model>: anthropic/claude-sonnet-5, openai/gpt-5.5, google/gemini-3.8-flash, xai/grok-4.7, deepseek/deepseek-v4-pro, moonshotai/kimi-k3, zai/glm-5.3, minimaxai/minimax-m3. The picker fetches the live catalogue from https://api.impossibl.com/v1/models and lists only the models Hermes can drive. It leaves out image, speech, transcription, embedding and rerank models, and any chat model that does not support tool calling.

What the profile sets

Field	Value
name / aliases	impossibl / impossibl.com, impossibl-ai
api_mode	chat_completions (streaming, tools, vision)
base_url	https://api.impossibl.com/v1 (override with IMPOSSIBL_BASE_URL)
env_vars	IMPOSSIBL_API_KEY, IMPOSSIBL_BASE_URL
default_aux_model	google/gemini-3.1-flash-lite (compression, titles, vision side tasks)
fallback_models	tool-calling models shown when the live catalogue is unreachable

Context windows come from models.dev, where impossibl is a listed provider.

Without the plugin

Hermes can already reach Impossibl as a named custom provider. Add this to ~/.hermes/config.yaml and use /model custom:impossibl:anthropic/claude-sonnet-5:

providers:
  impossibl:
    api: https://api.impossibl.com/v1
    key_env: IMPOSSIBL_API_KEY
    transport: chat_completions

The plugin adds the picker entry, aliases, hermes doctor checks, a chat-only model list and aux-model defaults on top of that.

Development

git clone --depth 1 https://github.com/NousResearch/hermes-agent.git /tmp/hermes-agent
pip install pytest pyyaml
PYTHONPATH=/tmp/hermes-agent pytest -q

The tests copy the plugin into a temporary $HERMES_HOME/plugins/hermes-impossibl/ and resolve it through Hermes' real discovery path.

License

MIT