MelonBot performs a variety of tasks related to the maintenance of WikiProject banners on article talk pages:
MelonBot replaces banners for projects which have been converted into task-forces of larger projects. In most cases, this requires replacing a template like {{WikiProject Foo|class=FA|importance=Top}} with something like {{WikiProject Bar|Foo=yes|class=FA|importance=top}}. Once all instances of the template have been converted, the original banner can be redirected to the larger one, or deleted.
MelonBot removes the banners of WikiProjects which have been deleted at an MfD discussion, prior to listing the template at TfD or for CSD. MelonBot will not be used to remove banners for WikiProjects which have merely been marked as "inactive"
MelonBot can add a particular banner to the talk page of all pages in a category or its subcategories, adding into a BannerShell if one already exists. Since other bots are faster and more efficient at tagging large batches of articles, MelonBot will tag only for small projects.
Poor use of <noinclude> or <includeonly> tags can result in all the pages where a template is transcluded appearing in a category when this is not desirable. For instance, WikiProject Banners are categorised into Category:WikiProject banners by placing the category tag in a <noinclude> tag. If this is not done, or done improperly, it is possible for all the talk pages where the banner is transcluded to also appear in that category. Although fixing the template will enable the problem to eventually be fixed, but the pages must work their way through the job queue before being recategorised, which often takes an unnecessary length of time. Null edits at a reasonable rate force a recompilation of the page and remove it from any categories in which it has been improperly placed. Null edits do not usually have any visible effect on the page, but may occasionally show up in edit history as the removal of whitespace: consequently, they (probably) require approval.
Occasionally banner templates are substituted, rather than transcluded, onto talk pages, which causes an ungainly mess of code to appear on the talk page, miscategorises the page into Category:WikiProject banners, and prevents future updates from taking effect. Normally these are fixed by hand but, if MelonBot detects that a substantial number of instances of a particular project banner have been substituted, it uses a simple find-and-replace to replace the substituted code with a template call to the banner.