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)

Related MCP server: kev-mcp

Install and configure

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:

{
  "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 into that file. Set DREX_API_KEY in the MCP server env mapping, then restart Hermes. See the Hermes-specific usage example.

Development and tests

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.

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