Currently, the maximum is 500 characters, which means we are missing 445 characters

500 - 155 = 345

500 UTF-8 Characters too, at that.

Unfortunately, we have a bit of a problem. MW doesn't expose how long the edit summary is. On older versions (older than 1.25 I guess), it's only 255 chars in the database, now it's 767, hard limited to 500

As only MW 1.27 is supported upstream, it wouldn't be unreasonable to increase that limit to > 500. It may cause problems for Wikia... but then they're using a version of MediaWiki that's effectively a fork at this point.

Some other features are known broken over there, and won't be fixed, as it's requiring old code

@Reedy My bad, I fixed the number. Would not be possible that we increase the limit only if a Wikipedia is chosen? Or are there any other options?

Forking the behavior based on selected site would be a maintenance nightmare (definitely in the long run, and probably so even in the near-term). If for some reason you actually did want to go that route, though, you'd want to set it up so Wikia was the exception, not WMF wikis (since there are many non-WMF wikis which use sanely recent versions of MediaWiki, and they are far more likely to have active, AWB-using communities than are significantly out-of-date installations{{citation needed}}).

In T199347#4417217, @Dinoguy1000 wrote:

Forking the behavior based on selected site would be a maintenance nightmare (definitely in the long run, and probably so even in the near-term).

I don't see any need for a fork. Just include an option to "enable long summaries (check that your site supports this)" ... with long summaries disabled by default.

If users enable long summaries on sites which don't support it, then I presume that the summaries will simply be truncated.

This would be a v useful fix which would allow much more informative summaries on en.wp. I don't see any needs for en.wp to be held back by a few smaller projects

Fandom is so far behind the times, I don't even see why there are efforts to even support it anymore. They clearly don't care about any upkeep. Just making money. Everybody over there should just move to Miraheze which is also a Wikifarm, and also free, but also free of ads, and community maintained.

Despite what Editor Reedy apparently believes, T297568 is not about the length of the edit summary output from awb but rather, it is about the number of characters that the 'default summary' text box on the start tab will accept as input. I think that T297568 and T199347 are separate issues; related, yes, but still separate. T199347 is an old (relatively) issue opened 2018-07-11. I know that edit summaries created with a c# module can be longer than the 155ish characters that the 'default summary' text box allows. By merging T297568 into this task, that distinction gets lost.

No need for the passive aggressive comments.

Feel free to make it a dependancy instead. Without this, the default edit summary being longer doesn't exactly help.