Editor Support
The Pipelex extension for VS Code-compatible editors (VS Code, Cursor, Windsurf, Antigravity, and others) provides syntax highlighting, semantic tokens, formatting, and validation for .mthds files. It is also available on Open VSX. It is the recommended way to work with MTHDS.
Installation
Install the Pipelex extension from the VS Code Marketplace:
- Open your VS Code-compatible editor.
- Go to Extensions (
Ctrl+Shift+X/Cmd+Shift+X). - Search for Pipelex.
- Click Install.
The extension activates automatically for .mthds files.
Features
Syntax Highlighting
The extension provides a full TextMate grammar for .mthds files, built on top of TOML highlighting. It recognizes MTHDS-specific constructs: pipe sections, concept sections, prompt templates, Jinja2 variables ({{ }}, @variable, $variable), and HTML content embedded in prompts.
Markdown code blocks tagged as mthds or toml also receive syntax highlighting when the extension is active.
Semantic Tokens
Beyond TextMate grammar-based highlighting, the extension provides 7 semantic token types that distinguish MTHDS-specific elements:
| Token type | Applies to | Visual hint |
|---|---|---|
mthdsConcept |
Concept names (e.g., ContractClause, Text) |
Type color |
mthdsPipeType |
Pipe type values (e.g., PipeLLM, PipeSequence) |
Type color, bold |
mthdsDataVariable |
Data variables in prompts | Variable color |
mthdsPipeName |
Pipe names in references | Function color |
mthdsPipeSection |
Pipe section headers ([pipe.my_pipe]) |
Keyword color, bold |
mthdsConceptSection |
Concept section headers ([concept.MyConcept]) |
Keyword color, bold |
mthdsModelRef |
Model field references ($preset, @alias) |
Variable color, bold |
Semantic tokens are enabled by default. To toggle them:
pipelex.mthds.semanticTokens— MTHDS-specific semantic tokens.pipelex.syntax.semanticTokens— TOML table/array key tokens.
Formatting
The extension includes a built-in formatter for .mthds and .toml files. It uses the same engine as the plxt CLI (see Formatting & Linting). Format on save works out of the box.
Formatting options are configurable in VS Code settings under pipelex.formatter.* (e.g., alignEntries, columnWidth, trailingNewline).
Schema Validation
The extension supports JSON Schema-based validation and completion for TOML files. When the MTHDS JSON Schema is configured (see MTHDS JSON Schema), the editor provides:
- Autocomplete suggestions for field names and values.
- Inline validation errors for invalid fields or types.
- Hover documentation for known fields.
Schema support is enabled by default (pipelex.schema.enabled).
Additional Commands
The extension contributes several commands accessible via the Command Palette:
| Command | Description |
|---|---|
| TOML: Copy as JSON | Copy selected TOML as JSON. |
| TOML: Copy as TOML | Copy selected text as TOML. |
| TOML: Paste as JSON | Paste clipboard content as JSON. |
| TOML: Paste as TOML | Paste clipboard content as TOML. |
| TOML: Select Schema | Choose a JSON Schema for the current TOML file. |