nullish

nullish exposes its actions as MCP tools, the same ones its built-in assistant uses. Connect any MCP-capable agent or client, like Claude, ChatGPT or your own, and do your bookkeeping from there.

Server: https://api.nullish.ch/mcp
Transport: streamable HTTP
Authentication: an API key, as a bearer token

Create an API key

In nullish, open the menu with your name and go to API keys, then choose Create API key.
Give it a Name, pick an Expiration, and choose MCP server as the Resource.
Pick the Access: Read gives your agent the tools that look things up, Read and write gives it all of them.
Copy the key. It isn't shown again.

Connect your client

With Claude Code:

claude mcp add --transport http nullish https://api.nullish.ch/mcp \
  --header "Authorization: Bearer nullish_…"

With clients configured in JSON:

{
  "mcpServers": {
    "nullish": {
      "type": "http",
      "url": "https://api.nullish.ch/mcp",
      "headers": {
        "Authorization": "Bearer nullish_…"
      }
    }
  }
}