Hermes Agent Integration

Hermes Agent is an open-source AI coding agent for your terminal built by Nous Research. It supports tool use, browser automation, multi-provider routing, skills, and MCP servers. By pointing it at LLM Gateway you get access to 210+ models from 60+ providers, all tracked in one dashboard.

One config change. No code changes. Full cost tracking.

Prerequisites

• Hermes Agent installed — see installation below or visit the Hermes Agent repo
• An LLM Gateway API key — sign up free (no credit card required)

Installation

Install Hermes Agent using the official install script:

curl -fsSL https://raw.githubusercontent.com/NousResearch/hermes-agent/main/scripts/install.sh | bash

After installation, reload your shell and verify:

source ~/.bashrc
hermes --version

Setup

hermes setup

API base URL: https://api.llmgateway.io/v1

Using Hermes with LLM Gateway

Once configured, all requests route through LLM Gateway. You'll see the provider name (e.g., "LLMGATEWAY") in the Hermes status bar.

Switching Models at Runtime

You can switch models mid-session using the /model slash command (similar to how Claude Code uses slash commands). Just type /model followed by the model name:

Switch to any model available through LLM Gateway — from Claude to GPT to open-source models — without leaving your session:

Add --global to persist the model change across sessions.

CLI Model Override

You can also override the model from the command line:

# Use a specific model for this session
hermes chat --model gpt-5.5

# Use a powerful model for complex tasks
hermes chat --model claude-opus-4-6

Why Use LLM Gateway with Hermes Agent

• 210+ models — Claude, GPT, Gemini, Llama, DeepSeek, and more
• One API key — Stop managing separate keys for each provider
• Cost tracking — See exactly what each session costs in your dashboard
• Response caching — Repeated requests hit cache automatically
• Automatic fallback — If a provider is down, requests route to an alternative
• Volume discounts — Check discounted models for savings up to 90%

One-Shot Mode

For scripting or CI pipelines, use the -q flag for a one-shot prompt:

hermes chat -q "Explain what this function does" -Q

The -Q flag enables quiet mode, suppressing the banner and spinner for clean output. For pure one-shot mode (no interactive session):

hermes chat -z "Generate a README for this project"

Useful Hermes Commands

Locking to a Specific Provider

By default, LLM Gateway automatically fails over to alternative providers if your chosen provider is experiencing downtime. To disable fallback and always route to one provider, you can add the header via Hermes's request configuration.

Troubleshooting

Model not found

If you get a "model not supported" error, check that your model ID matches exactly what's listed on the models page. Model IDs are case-sensitive.

Connection timeout

Verify your base_url is set to https://api.llmgateway.io/v1 (note the /v1 at the end). You can also check the HERMES_API_TIMEOUT environment variable if you're hitting timeouts on long-running requests.

Authentication errors

Make sure your api_key starts with llmgtwy_ and is valid. Check your dashboard to confirm the key is active.

Diagnosing issues

Run hermes doctor to check your configuration, connectivity, and credentials:

hermes doctor

Old config overrides

If you previously used a different provider (e.g., OpenRouter), make sure to update both provider and base_url fields. The provider must be set to "custom" for LLM Gateway. Also check ~/.hermes/.env for any leftover OPENROUTER_API_KEY or other provider keys that might take precedence.