SunPlot can be added as a tool to AI assistants. You ask about a Swiss address in the chat and get a short sun preview with the mountain horizon, plus the list of chapters the full report contains for that address. Free, no account, no sign-in.
For one address: sunrise and sunset behind the mountains on 21 December, 21 March and 21 June, the hours of direct sun on those days, for comparison the same figures without mountains, the highest point of the mountain horizon with its direction, the canton, the elevation and the list of report chapters for this address. Languages: German, French, Italian, English.
Only the chapter list: which of the 33 chapters of the SunPlot report exist for this address in full, in part or not at all (depending on canton and data), with a link to the report page.
What the preview is not: it only uses the terrain up to 100 kilometres, that is mountains and hills. Neighbouring houses, trees and the building itself are missing. Only the full report shows them, with the 3D model of all buildings and trees. The preview is an orientation, not a substitute for the report and not advice.
The interface uses the open MCP standard (Model Context Protocol). Any assistant that accepts custom MCP servers by address can add SunPlot. There are two addresses with the same tools; they differ only in the link at the end of the answer.
Address: https://sunplot.ch/mcp
In claude.ai or Claude Desktop, go to Settings, Connectors, “Add custom connector” and enter the address. Whether custom connectors are available on your plan is shown in Anthropic’s plan overview. In Claude Code a single command is enough:
claude mcp add --transport http sunplot https://sunplot.ch/mcp
Address: https://sunplot.ch/mcp-info
In ChatGPT, custom MCP servers are added in developer mode in the settings (Connectors or Apps). Availability depends on your ChatGPT plan and workspace settings; OpenAI’s instructions are authoritative. SunPlot is not yet listed in the ChatGPT app directory.
Add it as an MCP server of type “Streamable HTTP” with the address https://sunplot.ch/mcp. No key and no sign-in are needed.
Then ask in the chat, for example: “How is the sun in winter at Rathausgasse 1 in Aarau?” or “Which chapters does the SunPlot report contain for Lidostrasse 5 in Lucerne?”
Limits: the interface is meant for individual requests. Each caller may make 20 requests per hour, 60 in total per hour; the mountain horizon is limited further because its computation is expensive. With too many requests the tool answers with a waiting time.
Address and data: the interface reads public data only. No account is needed, we do not learn who is asking, and we store neither addresses nor results. What exactly is transmitted and how long server logs are kept is in the privacy policy, section 3a. The conversation itself takes place with the provider of your assistant.
Sources: terrain swissALTIRegio (Federal Office of Topography swisstopo) with elevation data of neighbouring countries, address, elevation and canton from geo.admin.ch, solar data SFOE Sonnendach, sun position after NOAA. Every answer names its sources. All datasets: Data & method.
Questions or outage: info@sunplot.ch. Changes to the tools are announced on this page. Last updated: 8 November 2026.
The full report uses the 3D model of all buildings and trees, as an interactive 3D report and PDF.
What the report contains