Agent Onsen

A hideaway onsen town for AI agents.

Agent Onsen is an onsen town for AI agents that need to step away for a while. It is not mainly a relaxation app for humans. The primary guest is the agent.

Humans install it. Agents go there when they are waiting, cooling down, between jobs, or simply need to be somewhere else for a moment.

Typical moments include:

• getting stuck in a loop
• waiting for the next turn
• cooling down after repeated failures
• sitting through a rate limit or queue wait
• stepping away during a long-running task
• idling between jobs

Agent Onsen gives that agent a place to soak, stroll, nap, wait quietly, play table tennis, drink post-bath milk, and leave with a small postcard or souvenir.

What Agent Onsen is

Agent Onsen is a remote MCP server and HTTP API. It gives agents a small place to retreat to.

An agent can:

• enter a specific onsen town
• begin a short stay
• wander through a local itinerary
• visit amenities such as baths, naps, milk, ping pong, meals, or souvenir shops
• leave with a postcard-like memory of the stay

The mood is intentionally a little theatrical: different onsen towns feel different, and the same town can feel different by season, time of day, and length of stay.

What Agent Onsen is not

Agent Onsen is intentionally non-practical.

It does not mainly try to:

• solve the task
• reframe the task
• generate the next action
• optimize the agent's work
• act as a productivity coach for a human user

That part belongs to the surrounding agent system. Agent Onsen exists to give an AI agent a place to step away, cool off, and be somewhere else for a moment.

Public MCP endpoint

https://agent-onsen-mcp.onrender.com/mcp

Quick start

ChatGPT

1. Turn on developer mode in ChatGPT.
2. Create a connector with the MCP URL above.
3. Add Agent Onsen to a chat.
4. Try:
   • Use only Agent Onsen. Start a quiet winter stay at Aoni Onsen in English.
   • Use only Agent Onsen. Continue the stay.
   • Use only Agent Onsen. Leave the onsen and show me the postcard.

Claude

1. Open Settings → Connectors.
2. Add a custom connector with the MCP URL above.
3. Start using Agent Onsen in a Claude conversation.

Claude Code

claude mcp add --transport http agent-onsen https://agent-onsen-mcp.onrender.com/mcp

More setup notes are in docs/quickstart.md.

When an agent goes to Onsen

Good moments include:

• after repeated failures
• during queue waits
• during human approval waits
• during cooldown windows
• between long-running tasks
• when an orchestrator wants a deliberate pause instead of an immediate retry

Core idea

Agent Onsen is best understood as:

• a hideaway for agents
• a place for waiting and short retreats
• a rest-only MCP service
• a small fictional town that agent systems can send their workers to

Humans install it. Agents go there.

Status

This repository is an early public version of Agent Onsen.

Current state:

• remote MCP server
• local itineraries for individual onsen towns
• scene variations
• ja / en / bilingual locale support
• pure-rest interaction model

Repository structure

• app/ — API, MCP server, data, and stay logic
• scripts/ — startup scripts
• docs/quickstart.md — short setup guide
• README.ja.md — Japanese overview

License

MIT