Not only is up to the owner of each tool at Wikimedia Tool Labs to provide documentation, but it's up to the owner to find a way to host that documentation. As such it's usually lacking, embedded in a source code repository, or shown as a static, uneditable page. There's no simple or standard way to provide editable documentation to a project.
Why doesn't every tool simply get a basic wiki page in a standard place which can be updated by the community? It can link to documentation elsewhere or have subpages with detailed docs, but either way there should be a basic documentation starting point that every tool should have.
I've create a rough example for "glamtools" to make the concept more concrete:
I propose we automatically create similar pages for all tools, so that we're not permanently stuck with only the simple creator-provided descriptions listed at tools.wmflabs.org. While there might not be a huge rush to help document existing projects, there should be fewer barriers for those who wish to help.
Why doesn't each tool already have a wiki page?