How to install the VS Code extension for .sdd files

How-To Editor setup Beginner 1031000HOWTO-1031000

HOWTO-1031000Editor setupBeginner

This guide shows you how to install the SpecDD extension for Visual Studio Code and compatible editors so .sdd files are recognized as SpecDD specifications.

The extension adds editor support for SpecDD files while keeping specs as plain text in your repository.

Prerequisites

You need one of these editors:

Visual Studio Code
a compatible editor that supports VS Code-style extensions
a compatible editor that uses Open VSX

You also need a project that contains .sdd files, or a project where you can create one for testing.

Steps

1. Choose the marketplace for your editor

For Visual Studio Code, use the SpecDD extension on Visual Studio Marketplace .

For compatible editors that use Open VSX, use the SpecDD extension on Open VSX .

If your editor has its own extension gallery, open that gallery and search for SpecDD.

2. Install from the editor UI

In Visual Studio Code:

Open Extensions.
Search for SpecDD.
Select the extension published by SpecDD.
Click Install.

For compatible editors, use the same search term and select the SpecDD extension from the marketplace your editor uses.

3. Install from the command line instead

If the code launcher is available, install the extension with:

code --install-extension specdd.specdd

For compatible editors, replace code with that editor’s launcher only when it supports VS Code-style extension installation.

4. Open the project folder

Open the repository or workspace folder that contains your SpecDD files.

This matters because editor features such as document links, related-spec commands, and workspace validation need a project boundary. For most projects, that boundary is the repository or workspace root. In a monorepo, open the root that contains the specs that may refer to each other.

5. Open a `.sdd` file

Open an existing spec, or create a minimal file:

Spec: Editor Check

Purpose:
  Verify that the editor recognizes SpecDD files.

Save it with the .sdd extension.

How to verify the result

The extension is working when a .sdd file has SpecDD editor behavior:

semantic syntax highlighting appears
invalid structure is reported as diagnostics
sections appear in document symbols
folding works for sections
completions and hovers appear while editing
explicit path and glob references can become document links
SpecDD file icons appear in the file tree

If the editor exposes SpecDD commands in the command palette, check that related-spec and workspace validation commands are available there.

Common mistakes

Installing a similarly named extension instead of the one published by SpecDD.
Testing in an unsaved file that does not have the .sdd extension.
Opening only a nested src folder when / paths should resolve from the repository or monorepo root.
Expecting the editor extension to initialize SpecDD project files. Use the SpecDD CLI for project setup.
Using the Visual Studio Marketplace in an editor that expects Open VSX extensions.

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