# Drex MCP

Drex MCP exposes Nace.AI Drex as a bounded closed-decision tool for MCP-compatible agents. The agent supplies a question, explicit choices, and optional evidence/context; Drex returns a selected choice and probabilities. The agent remains responsible for deciding whether and how to act.

The server is a thin stdio MCP adapter to the public Drex API. It does not provide general conversation, execute the selected action, or contain a separate decision engine.

## Requirements

- Python 3.10+
- A Nace.AI Drex API key
- An MCP client (Hermes Agent is supported through its documented stdio MCP configuration)

## Install and configure

```sh
git clone https://github.com/colt2822/Drex-MCP.git
cd Drex-MCP
python -m venv .venv
. .venv/bin/activate
python -m pip install -e '.[test]'
export DREX_API_KEY='your_api_key_here'
```

The server reads `DREX_API_KEY` from its process environment. It makes an HTTPS request to the fixed public Drex endpoint with a 30 second request timeout and 5 second connect timeout. It does not print provider responses, credentials, or exception text.

## Tool

`drex_decide(question, choices, evidence="")`

- `question`: non-empty string, up to 2,000 characters
- `choices`: 2–12 non-empty string labels, each up to 200 characters
- `evidence`: optional string, up to 6,000 characters

The input becomes Drex's supported `state` and `questions.decision` choice schema. No unsupported API metadata is sent.

Success result:

```json
{
  "ok": true,
  "result": {
    "choices": {"retry_1": "Retry", "escalate_2": "Escalate", "stop_3": "Stop"},
    "choice": "retry_1",
    "probabilities": {"retry_1": 0.8, "escalate_2": 0.15, "stop_3": 0.05},
    "confidence": 0.8,
    "latency_ms": 123.45
  }
}
```

Errors use `{"ok": false, "error": {"code": "...", "message": "..."}}`; an upstream HTTP status is included when available. API response bodies and secrets are not included.

## Hermes Agent

Hermes reads MCP servers from `~/.hermes/config.yaml`. Install this package in the environment available to Hermes and merge [examples/hermes/config.yaml](examples/hermes/config.yaml) into that file. Set `DREX_API_KEY` in the MCP server `env` mapping, then restart Hermes. See [the Hermes-specific usage example](examples/hermes/README.md).

## Development and tests

```sh
python -m pip install -e '.[test]'
pytest
```

The standalone tests stub the network and do not make paid Drex calls. Separately, one direct MCP canary and one Hermes Agent canary each made a single live Drex API request during release validation.

## Compatibility

The API request and response validation follows the public `drex-latest` `/v1/systemone` choice schema used by Drex OpenWebUI Bridge v0.1.0. Python 3.10+ and MCP Python SDK 1.x are targeted. Hermes Agent v0.20.4 was verified with the example configuration for stdio connection, tool discovery, and one live tool call to Drex.

## License

MIT. See [LICENSE](LICENSE).

Unofficial community integration for Nace.AI Drex and Hermes Agent. This project is not an official Nace.AI or Hermes project unless explicitly endorsed.