42-evey
evey-cost-guard
Budget enforcement plugin for Hermes Agent using Langfuse cost tracking.
Repository last updated Jul 18, 2026
Overview
Evey Cost Guard is a plugin for Hermes Agent that enforces budget limits by tracking costs via Langfuse. It monitors daily and per-task spending, providing warnings at 80% usage and alerts when the budget is fully consumed.
This plugin helps developers and operators keep AI agent costs under control without manual oversight. It integrates directly with the Hermes Agent ecosystem and Langfuse's cost tracking capabilities.
Ideal for teams running autonomous agents who need predictable spending and automated budget enforcement.
Highlights
- Tracks daily and per-task costs via Langfuse
- Warns at 80% budget usage
- Alerts at 100% budget consumption
- Enforces budget limits automatically
Features
Cost Tracking
Monitors spending per task and per day using Langfuse's cost data.
Budget Alerts
Sends warnings at 80% usage and alerts when the budget is exhausted.
Automatic Enforcement
Stops or restricts agent actions when the budget limit is reached.
Installation
Commands are reproduced exactly as published by the project maintainers. Always check the upstream repository for the current instructions.
git clone https://github.com/42-evey/hermes-plugins.git
cp -r hermes-plugins/evey-* ~/.hermes/plugins/
cp hermes-plugins/evey_utils.py ~/.hermes/plugins/
# Restart hermes-agentRequirements
- Hermes Agent installed
- Langfuse account and API key configured
How it's built
The plugin is written in Python and follows the standard Hermes Agent plugin structure. It consists of a plugin.yaml manifest and an __init__.py module. The plugin integrates with Langfuse to retrieve cost metrics and compares them against configured budget thresholds.
Repository layout: evey-cost-guard/ contains __init__.py and plugin.yaml. No additional dependencies beyond Hermes Agent and Langfuse are required.
Source
This summary was written for Neura Market from the project's own repository. Install commands, identifiers and licence details are reproduced unchanged. The 42-evey/evey-cost-guard repository is the authoritative source and the place to file issues or contribute.
Category: Cost & Governance · Licensed under MIT