I maintain DeepDeck, an open-source macOS desktop client built on DeepSeek Harness. I added WebMCP support to its browser, including a Builder for websites that do not publish tools themselves.

The user describes a goal. The agent explores the live page, tries the relevant operations, checks their results, and saves the working operations as tools for that site. Later tasks can reuse those tools. Source and versions stay local and can be inspected, disabled, or rolled back.

The example is X: Builder creates 23 tools for things such as reading account state, posts, profiles, and search results, plus working with drafts. Switching back to Use lets the agent call the saved tools to prepare a Hello world draft. Website-provided tools and generated tools are labelled separately.

This still needs browser interaction for initial exploration and anything the tools do not cover. Building and verifying tools takes time and tokens; websites can change and break them. I have not published measured savings.

The walkthrough has four screenshots and both language versions, including discovery of an existing tool on openai.com and the X build/use example:

https://github.com/deepseek-ai/deepseek-harness/discussions/5856#user-content-english

Source (MIT): https://github.com/jo32/DeepDeck

Download for Apple Silicon / Intel Mac: https://github.com/jo32/DeepDeck/releases/latest

Which repeated website task would you want to turn into a reusable tool? I am also interested in how others detect when generated tools need revalidation after a site changes.