Helix

Helix has first-class tree-sitter + LSP support, configured via TOML. httui-lang plugs in with a single languages.toml entry plus a one-time grammar fetch.

Install

1. The LSP binary

cargo install httui-lsp

Verify it’s on PATH:

httui-lsp --version

2. Tell Helix about the language

Edit ~/.config/helix/languages.toml:

[[language]]
name = "httui"
scope = "source.httui"
file-types = ["httui"]
roots = [".httui", "runbooks", "connections.toml", "envs"]
comment-token = "#"
indent = { tab-width = 2, unit = "  " }
language-servers = ["httui-lsp"]

[language.auto-pairs]
'{' = '}'
'"' = '"'
"'" = "'"
'(' = ')'

[language-server.httui-lsp]
command = "httui-lsp"

[language-server.httui-lsp.config]
httui = { env = "staging" }

3. The tree-sitter grammar

Append to languages.toml:

[[grammar]]
name = "httui"
source = { git = "https://github.com/httuicom/tree-sitter-httui", rev = "main" }

Then build it:

hx --grammar fetch
hx --grammar build

hx --health httui should now report the grammar as installed.

4. Highlight queries

Helix needs the highlight queries in ~/.config/helix/runtime/queries/httui/:

mkdir -p ~/.config/helix/runtime/queries/httui
cd ~/.config/helix/runtime/queries/httui
curl -O https://raw.githubusercontent.com/httuicom/tree-sitter-httui/main/queries/highlights.scm
curl -O https://raw.githubusercontent.com/httuicom/tree-sitter-httui/main/queries/injections.scm
curl -O https://raw.githubusercontent.com/httuicom/tree-sitter-httui/main/queries/folds.scm

(Future: these will ship with the grammar fetch automatically when Helix’s runtime supports vendored queries.)

Markdown integration

To get httui injection inside .md fenced blocks, Helix needs the markdown injection query updated. Add to ~/.config/helix/runtime/queries/markdown/injections.scm (extend, don’t replace):

((fenced_code_block
  (info_string (language) @lang)
  (code_fence_content) @injection.content)
 (#match? @lang "^(http|db-)")
 (#set! injection.language "httui"))

After this, fenced httui blocks inside markdown highlight correctly.

Verify

hx ~/runbooks/runbooks/example.httui

Inside Helix:

:lsp-info — should show httui-lsp running
Hover an {{...}} reference (default Space+k) — popup with resolved value
gd on a reference — jumps to alias definition
Space+r — rename
Space+a — code actions

Active environment

The env setting passes through to the LSP. Edit it in languages.toml and reload (:reload).

To switch per-buffer, use the LSP workspace configuration change — Helix doesn’t have a built-in UI for this yet, but you can run:

:lsp-workspace-command httui.setEnv staging

(Custom commands exposed by httui-lsp per session.)

Snippets

Helix has minimal snippet support. The httui-lsp ships completion items with snippet bodies — typing http and confirming the completion expands the scaffold. Same for db, expect, expect.status, etc.

Run blocks from Helix

Same pattern as Neovim — shell out to httui-tui:

[keys.normal.space.h]
r = ":sh httui-tui run %{buffer_name} --env staging"

Space+h+r runs the current runbook in the TUI alongside Helix.

For inline run-and-show-result, the httui desktop app must be open on the same vault — then the LSP forwards to it via httui/blockRun.

Troubleshooting

`:lsp-info` shows “Not started”

Check hx --health httui:

Output	Meaning
`✓ httui-lsp`	LSP binary on PATH
`✗ httui-lsp: command not found`	Install the binary
`✓ grammar httui`	Tree-sitter parser built
`✗ grammar httui: not found`	Re-run `hx --grammar fetch && hx --grammar build`

Highlight inside markdown fences not working

The markdown injection query must explicitly mention httui (Helix doesn’t auto-inherit). See the injection snippet in Markdown integration above.

LSP attached but no diagnostics

Open :log (the LSP log) and search for httui. Common: vault root not detected because the file isn’t under a folder containing .httui / runbooks / connections.toml. Workaround: create an empty connections.toml.

Theme integration

Helix highlight groups in your theme will pick up:

Highlight scope	Recommendation
`keyword`	HTTP verb, language identifier
`function`	block aliases in references
`constant`	env var keys
`string`	URLs, header values, literals
`variable.parameter`	reference inner identifiers

Most themes already map these — no httui-specific work needed.

LSP capabilities — what the server provides
Tree-sitter grammar — what the parser produces
Neovim setup — similar plugin model