Is setting capabilities really necessary?

[Shaobin-Jiang]

Using neovim 0.10.4 and just removed the setting of capabilities from my nvim-lspconfig. Completion still works like a charm. Makes me wonder whether the specific instruction here that asks to set capabilities to nvim-lspconfig is really necessary?

[Saghen]

Some LSPs won't behave correctly without them (i.e. jdtls) but generally speaking you don't need the capabilities. With them though, we can:

• Tell the LSP not to return some properties and to send us defaults for others, which sometimes reduces latency
• Request label descriptions for items (such as the module that will be auto-imported on accept)
• Get replace ranges for replacing the text before and after the cursor optionally

And I'm likely missing some others