Languages

Language support is layered. Every file in the repo gets syntax highlighting, a file-type icon, and structural folding, whatever the language. Language servers add diagnostics for the languages the table marks, TypeScript and Rust get full code navigation on top, and you can wire anything else up through your config.

Syntax highlighting

Any language Shiki bundles highlights out of the box, 200 and counting. stet picks the grammar from the file's name, exact names like Dockerfile included, and loads it on demand. Every surface that shows code shares the same highlighter and theme: the diff, the full file, search results, hover cards, and reference previews. A file type nothing recognizes falls back to plain text.

Folding

Press z to fold the block at the caret: code folds by indentation in every language, markdown folds by heading section. See reading files and diffs.

File icons

The tree shows a Nerd Font icon per file type, resolved by exact filename first, then extension. Pass --no-icons for a plain tree if your terminal font lacks the glyphs.

Diagnostics

Servers overlap deliberately: every server that claims a file runs, and their findings merge per file, each tagged with its own source label. A linter that competes with an always-on default activates only where the repo opted into it, the way an editor extension would.

TypeScript & JavaScript

.ts, .tsx, .js, .jsx, and the .mts/.cts/.mjs/.cjs variants run through three servers: typescript-language-server reports type errors (label typescript), oxlint reports lint findings (label oxc), and Biome joins them (label biome) when the repo has a biome.json or biome.jsonc.

Rust

.rs files get rust-analyzer's own analysis (label rust-analyzer) plus the findings cargo check produces through it (label rustc). stet downloads the server automatically the first time a Rust file needs it.

JSON & JSONC

vscode-json-language-server validates against schemas (package.json, tsconfig.json, and anything SchemaStore knows) in every repo, and Biome adds its lint where configured.

YAML

yaml-language-server provides schema-aware validation for .yaml and .yml.

CSS & GraphQL

Biome covers both, only in repos with a biome config. Without one these files show as unavailable rather than falsely clean.

Code intelligence

Go to definition, find references, implementations, call hierarchy, hover, and the symbol outline work for the TypeScript & JavaScript family and for Rust, through the same servers that produce their diagnostics. See code intelligence for the keys and flows.

How servers are found

A server resolves from the repo's own node_modules/.bin, then your PATH. If neither has it, stet downloads one into ~/.cache/stet/lsp, pinned to an exact version: npm packages for the servers npm distributes (this path needs npm on your PATH), or a sha256-verified GitHub release binary for rust-analyzer. Pass --no-lsp-download (or set STET_NO_LSP_DOWNLOAD) to turn downloads off.

Add your own languages

The languages config key routes any file type to any language server on your machine, and can change which servers run for the built-in languages:

{
  "languages": {
    "python": {
      "extensions": ["py"],
      "servers": [{ "command": ["pyright-langserver", "--stdio"] }],
    },
  },
}

Servers you name are any executable on your machine; stet resolves them locally and never runs a command the inspected repository ships. See configuration for the full shape: filename routing, server options, and overriding built-ins.