Manual setup · Windows, macOS and Linux

Hermes Agent + Space Router

Hermes Agent is an open-source agent from Nous Research that runs as a persistent background process and accepts any custom model endpoint. Pointing it at Space Router takes five configuration commands.

Gateway: https://space.stationine.com · Last checked: 2026-09-13

There is no one-command installer for Hermes. Install Hermes first by following its own documentation and confirm that hermes runs in your terminal, then come back here.

Before you start

You need one Space Router API key. Its group decides both the models you can call and which of the two routes you configure. Create the key in the Space Router dashboard under API Keys → Create API Key, choosing the matching group.

Key group	Route	Model slugs
Claude (group 3)	Anthropic Messages	claude-opus-5, claude-sonnet-5, claude-opus-4-8, claude-opus-4-7, claude-opus-4-6, claude-sonnet-4-6
Claude Fable 5 (group 5)	Anthropic Messages	claude-fable-5
GPT (group 4)	OpenAI-compatible	gpt-6-astra, gpt-5.6-sol, gpt-5.6-terra, gpt-5.6-luna, gpt-5.5, gpt-5.4, gpt-5.4-mini

A key only works inside its own group. A Claude key asking for gpt-5.5, or a Claude key asking for claude-fable-5, gets a hard error rather than a fallback — Fable is a separate purchase. The live catalogue is published at /models.json.

Step 1 · Find the config file

1. Print the path

   Open a terminal and run this. It tells you exactly which file the next step will write, which is worth knowing before you change anything.

   hermes config path

2. Compare it with the default

   macOS and Linux

   ~/.hermes/config.yaml

   Windows

   %LOCALAPPDATA%\hermes\config.yaml

   If the printed path is somewhere else, Hermes is using a non-default config — everything below still applies, it just lands in that file instead.

3. Back it up if it already has settings

   The commands in step 2 overwrite the model. keys only, but a copy costs nothing.

   cp ~/.hermes/config.yaml ~/.hermes/config.yaml.bak

Step 2 · Set the custom provider

Run the block for your key group. Each line is a separate command; run them in order.

Claude or Fable key — the Anthropic Messages route

1. Run the five commands

   hermes config set model.provider custom
   hermes config set model.base_url https://space.stationine.com
   hermes config set model.api_mode anthropic_messages
   hermes config set model.api_key sk-your-space-router-key
   hermes config set model.default claude-sonnet-5

2. Note the base URL has no suffix

   anthropic_messages mode appends /v1/messages itself, so the value stops at the gateway root. Adding /v1 here produces a 404 that looks like a wrong key.

GPT key — the OpenAI-compatible route

1. Run the four commands

   hermes config set model.provider custom
   hermes config set model.base_url https://space.stationine.com/v1
   hermes config set model.api_key sk-your-space-router-key
   hermes config set model.default gpt-5.6-sol

2. Do not set model.api_mode at all

   The OpenAI route is the absence of that setting. Here the base URL does end at /v1, because Hermes appends /chat/completions itself.

Step 3 · Check what was written

Open the file from step 1. The commands produce this block, and you can edit it directly instead of re-running them.

model:
  provider: custom
  base_url: https://space.stationine.com
  api_mode: anthropic_messages
  api_key: sk-your-space-router-key
  default: claude-sonnet-5

Two things to confirm: the four or five keys are all present, and there is no leftover setting from a previous provider sitting under model:.

Step 4 · Verify

1. Start Hermes

   If it was already running as a background process, restart it so it reloads the configuration.

2. Send one short message

   Send Reply with OK. A reply proves the base URL, the key, the route and the model slug are all correct together. Reading the config file back proves none of those — only a real request does.

Switching routes later

Moving from the Anthropic route to the OpenAI route is not just a base-URL change: you must also clear model.api_mode. A leftover anthropic_messages against a /v1 base URL is the single most confusing failure on this page, because the key and the model are both fine and the error is a bare 404.

Troubleshooting

What you see	What it means
401 or 403	The key is wrong, revoked, or out of balance. Re-copy it from the dashboard and check for a leading or trailing space.
404	The base URL and the route disagree — /v1 with api_mode: anthropic_messages, or the bare root without it. Can also be a misspelled model slug.
The model is rejected as unsupported	The slug belongs to a group your key does not have. Compare it against the table above.
It fails on the very first tool call	The selected model does not support function calling, which Hermes requires on every request.
The change had no effect	The background process was not restarted, or hermes config path points somewhere other than the file you edited.

What is Space Router?

Space Router is an AI API relay operated by Station Nine. Its base URL is https://space.stationine.com. It accepts Anthropic Messages requests at POST /v1/messages, OpenAI Chat Completions requests at POST /v1/chat/completions, and OpenAI Responses requests at POST /v1/responses, and it provides OpenAI GPT and Anthropic Claude model families. See the full Space Router overview for service and account details.

Need credentials? Get your API key from Space Router.