Hi Chia-Ping, I’m going to jump in and get the discussion started. My view is that the output of the console tools is NOT a formal public interface. If it was, the KIPs would have to be totally explicit in the specification of the output formats, down to the spacing, column widths in tables, blank lines and so on. We would also need a major release to make even minor formatting changes unless they were protected by an option.
I think the console tools are wrappers around the admin API, and that’s the public interface. If someone wants to build automation around Kafka, it would be much better to use the admin API rather than the console tools. For interfaces which are intended to have a human using them directly, I think we should be prepared to improve them in ways that a human will instantly understand but which might confuse a piece of unsophisticated software capturing and parsing the output. In a similar vein, would the log lines produced by a broker be considered a public interface? People will certainly be scraping those to understand broker information. I’d say that the log lines should also not be considered a formal public interface. I don’t think we want people relying on specific strings in the log lines, or the order in which they are emitted. Just my 2 cents, Andrew On 29 Nov 2025, at 20:02, Chia-Ping Tsai <[email protected]> wrote: hi all, I opened KAFKA-19941 to improve the feature tool output, but now we face a compatibility question: Does our definition of a public interface, which includes "monitoring" and "command line tools" (per the KIP page), cover the output format? any feedback? Best, Chia-Ping
