VS Code

The httui-lang extension for VS Code bundles tree-sitter highlight + the LSP server in one install. Works on .httui files and on .md runbooks (fenced regions only).

Install

From the Marketplace

1. Open VS Code.
2. Extensions panel (Cmd+Shift+X).
3. Search “httui”.
4. Install httui-lang (publisher: httuicom).

Or from the command line:

code --install-extension httuicom.httui-lang

From a .vsix

If you want to side-load a pre-release:

1. Download httui-lang-<version>.vsix from Releases.
2. Extensions panel → ⋯ menu → Install from VSIX.

What you get

• Syntax highlight for .httui files (via TextMate grammar + tree-sitter when VS Code’s tree-sitter pipeline enables)
• LSP: hover, completion, go-to-definition, diagnostics, rename
• Snippets: http, db, expect → expandable scaffolds
• Run code lens at the top of each block (if the httui desktop app is also running — sends a message to it via the httui/blockRun extension)

Configuration

The extension reads vault config automatically when you open a folder that looks like a vault (has .httui/, runbooks/, connections.toml, or envs/).

Or set manually in settings.json:

{
  "httui.vault": "/Users/you/runbooks",
  "httui.env": "staging",
  "httui.lspPath": "auto",
  "httui.runCodeLens": true,
  "httui.diagnosticsLevel": "warning"
}

Setting	Default	Notes
httui.vault	auto	Path to the active vault; auto = current workspace folder if it looks like a vault
httui.env	from user.toml	Active environment for hover/resolution
httui.lspPath	auto	Path to httui-lsp binary; auto = bundled with the extension
httui.runCodeLens	true	Show “Run” lens above each block (no-op if desktop isn’t running)
httui.diagnosticsLevel	warning	off, error, warning, info
httui.format.onSave	false	Auto-format on save

Commands

Cmd+Shift+P then search:

Command	Action
httui: Set active environment…	Pick from envs/*.toml
httui: Run block under cursor	Sends to httui desktop if running
httui: Run all blocks in file	Same
httui: Show resolved value	Pop-over with current resolution of {{ref}} under cursor
httui: Open vault	Folder picker for vault path
httui: Restart LSP server	When the LSP gets confused, faster than reloading window

Keybindings

Default bindings (override in keybindings.json):

Action	macOS	Linux/Windows
Run block under cursor	Cmd+Shift+R	Ctrl+Shift+R
Show resolved value	Cmd+K Cmd+R	Ctrl+K Ctrl+R
Go to alias definition	F12 (standard go-to-def)	F12

Snippets

Type the trigger and press Tab:

Trigger	Inserts
http	HTTP block scaffold
httpa	HTTP block with alias=
httpexpect	HTTP block + # expect: section
db	DB block scaffold
expect	Just an # expect: section

Markdown integration

When you open a .md file with httui fence blocks, the extension injects httui language behaviour into the fenced regions:

• The fence’s body gets httui highlight + LSP
• Hover/completion/diagnostics work inside the fence
• Outside the fence, normal markdown behavior

No special config needed — the injection rules ship with the extension.

Troubleshooting

LSP not starting

Check the Output panel → “httui-lang” channel. Most common:

Symptom	Likely cause	Fix
”Couldn’t find httui-lsp”	Bundled binary not extracted	Reinstall extension; or set httui.lspPath to a manually-installed binary
LSP starts then exits	Vault config error	Open connections.toml / envs/*.toml and check syntax
No completions	LSP started but vault not detected	Set httui.vault explicitly

Tree-sitter highlight not working

VS Code’s tree-sitter pipeline is opt-in for some users. Fallback is TextMate (ships with the extension) — same colors, slightly less precise. To force tree-sitter:

{
  "editor.experimental.useTreeSitter": true
}

LSP slow on large vaults

If you have >100 runbooks, hover/completion can lag on first open. Solution:

{
  "httui.workspaceIndexing": "lazy"
}

Lazy mode indexes a runbook only when opened, vs eager (all on startup).

Related

• LSP capabilities — what the server provides
• Neovim setup — same LSP, different host
• Tree-sitter grammar — what powers highlight