Line Highlight

Highlight editor lines from JSON files. Highlights are file-based, not stored in VSCode internal state, so they work with version control, external tools, and AI assistants.

Claude Code / AI assistant setup

Add this to your CLAUDE.md or AGENTS.md:

Line highlights (vscode extension):
- When emphasizing lines in editor, write `.vscode/highlights/<path__to__file.ext>.json`
- Format: `[{"line": 1, "color": "green", "note": "optional"}]`
- Colors: green, red, yellow, blue, purple
- Ranges: `"line": "3-7"`, `__` = path separator in filename

Any tool that writes the JSON file triggers the extension via file watcher:

echo '[{"line": 42, "color": "red"}]' > .vscode/highlights/src__app.py.json

Features

• Full line background highlighting with 5 named colors
• File-based: plain JSON in .vscode/highlights/, git-committable, no VSCode Settings Sync needed
• Tool-friendly: AI assistants, scripts, CI can write highlights programmatically
• Right-click context menu to highlight/remove
• Command palette toggle with color picker
• Highlights track line positions through edits (auto-shift on insert/delete)
• Overview ruler marks near scrollbar
• Optional gutter bar
• All colors configurable
• Multi-root workspace support

How it works

Highlights are stored in .vscode/highlights/<path>.json per workspace. Filename maps to source file with __ as path separator:

.vscode/highlights/src__app.py.json  →  src/app.py

JSON format

[
  {"line": 12, "color": "red", "note": "optional hover tooltip"},
  {"line": "3-7", "color": "green"}
]

Context menu

Right-click any line or selection → "Line Highlight" → pick color. Same color again removes it.

Command palette

Ctrl+Shift+P → "Line Highlight: Toggle Highlight on Line" → pick color.

Ctrl+Shift+P → "Line Highlight: Clear All Highlights" → removes all highlights and deletes JSON files.

Settings

Install

npm run package
code --install-extension line-highlight-0.0.1.vsix

License

MIT