hermes-opper

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

Opper is the EU-hosted AI gateway: 700+ models from 30+ providers behind one OpenAI-compatible API, one key, no markup on provider rates. This plugin registers the opper provider profile so hermes model, --provider opper, 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 opper-ai/hermes-opper --enable
echo 'OPPER_API_KEY=<your key>' >> ~/.hermes/.env   # create one at https://platform.opper.ai
hermes model                                        # choose "Opper", then a model

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

model:
  provider: opper
  default: claude-sonnet-4-6

Then check with hermes doctor (probes OPPER_API_KEY and https://api.opper.ai/v3/compat/models).

Model ids

Use bare pool names: claude-sonnet-4-6, claude-opus-5, gpt-5.5, gpt-5.4-mini, gemini-3.8-flash, deepseek-v4-pro, kimi-k3, mistral-large-2512. A pool is every provider serving that model; Opper picks the route per request (cheapest, fastest, or EU-pinned via Control Plane rules). To pin one provider or region, prefix it: anthropic/claude-sonnet-4-6, azure/gpt-5.5, aws/claude-sonnet-4-6-eu. The picker fetches the live catalogue from /v3/compat/models; the full route list is at https://opper.ai/models.

Switch mid-session with /model opper:gpt-5.4-mini.

What the profile sets

Field	Value
name / aliases	opper / opper-ai, opperai, opper.ai
api_mode	chat_completions (streaming, tools, structured output)
base_url	https://api.opper.ai/v3/compat (override with OPPER_BASE_URL)
env_vars	OPPER_API_KEY, OPPER_BASE_URL
default_aux_model	gpt-5.4-mini (compression, titles, vision side tasks)
fallback_models	tool-calling pools shown when the live catalogue is unreachable

Without the plugin

Hermes can already reach Opper as a named custom provider. Add this to ~/.hermes/config.yaml and use /model custom:opper:claude-sonnet-4-6:

providers:
  opper:
    api: https://api.opper.ai/v3/compat
    key_env: OPPER_API_KEY
    transport: chat_completions

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

Pricing and residency

Token rates are the model providers' rates with no markup. Opper charges a 3% fee when you buy credits (5.5% with Control Plane features). Pay-as-you-go, no subscription. Hosted in the EU (AWS Stockholm); requests can be pinned to EU-hosted regions, and audit logs and traces stay in EU storage. Details: https://opper.ai/pricing, https://opper.ai/llm-gateway.

Development

git clone --depth 1 --filter=blob:none --sparse https://github.com/NousResearch/hermes-agent.git /tmp/hermes-agent
(cd /tmp/hermes-agent && git sparse-checkout set --cone providers plugins/model-providers hermes_cli)
pip install pytest pyyaml
PYTHONPATH=/tmp/hermes-agent pytest -q

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

License

MIT