The possibility to add custom language servers in configuration only

[eproxus]

When trying to understand the documentation regarding language server configuration, I kind of guessed that something like this should be possible:

    "languages": {
        "SQL": {
            "language_servers": [
                "sql-language-server"
            ],
        }
    },
    "lsp": {
        "sql-language-server": {
            "binary": {
                "path": "sql-language-server",
                "arguments": [
                    "--method",
                    "stdio"
                ]
            },
            "filetypes": [
                "sql"
            ],
        }
    },

However, Zed just reports this in the log:

[WARN] no language server found matching 'sql-language-server'

There are also some documentation and a lot of comments suggesting custom language servers has to have an extension for them to work.

Why is it not possible to add a custom LSP configuration that uses an external binary? Isn't that the promise of LSP, that you don't have to implement custom support in each and every editor?

Is it simply because Zed doesn't have any support for this (e.g. in contrast to Sublime LSP or other editors) and only has a model where it requires extensions?

[SomeoneToIgnore]

Is it simply because Zed doesn't have any support for this (e.g. in contrast to Sublime LSP or other editors) and only has a model where it requires extensions?

Precisely.

[henrybarreto]

Zed is a really great tool, but that feature is blocking my fully migration to it. I hope they have plans for it.

[hmemcpy]

Sorry for the "me too" message, but it would be great if it were possible to add/extend Zed with a custom LSP server from configuration only, without having to add a custom extension.
In particular, I wanted to add support for RustOwl - an LSP server that highlights lifetime and ownership in Rust, to work alongside the existing rust-analyzer. And it seems that it's not possible to add just from the config.

It would be great to have support for that!