Comment Lens
Show definition comments and symbol documentation inline at reference sites as VS Code inlay hints.
简体中文 | English
Why
Comment Lens keeps useful documentation close to the code you are reading. When a referenced symbol has a doc comment, JSDoc, docstring, Javadoc, PHPDoc, or language-service hover documentation, the extension renders the first useful summary at the end of the reference line.
It is designed for reading and navigation, not for changing your source. Comment Lens does not generate comments, rewrite files, highlight TODO tags, or index comment anchors.
What It Shows
Comment Lens scans visible identifiers, asks the active VS Code language service for hover and definition information, then renders concise documentation as an inlay hint.
It is useful for:
- Reading code that uses documented functions, constants, variables, methods, enum members, and object properties.
- Surfacing documentation from definitions without jumping away from the current file.
- Keeping inline hints short, display-only, and easy to ignore when you do not need them.
- Checking whether the current language service can provide useful documentation.
Hints are rendered at the end of the source line so they do not split expressions in the middle of a statement. The default prefix is // and the default summary limit is 120 characters.
Language Support
| Level |
Languages |
Notes |
| Stable |
Go, TypeScript, JavaScript, TSX, JSX |
Covered by the core path and automated fixtures. |
| Experimental |
Python, Java, Rust, PHP |
Uses adapter-backed behavior with source-comment fallback where available. |
| Hover-only |
C#, Ruby, Kotlin, Swift, C, C++ |
Depends on the installed language service's hover and definition quality. |
Install the recommended language extensions for non-built-in languages. Go works best with the official Go extension and gopls; Python works best with Python plus Pylance; Rust works best with rust-analyzer.
See the language support matrix for support levels, recommended dependencies, fallback strategies, and validation status.
Commands
| Command |
Purpose |
Comment Lens: Toggle |
Enable or disable inline documentation hints. |
Comment Lens: Refresh |
Clear cached lookup results and refresh hints. |
Comment Lens: Show Language Status |
Inspect whether the current file's language service is ready, degraded, missing dependencies, or unknown. |
Language Service Status
Run Comment Lens: Show Language Status from the command palette to inspect the active file. The status check verifies recommended extensions, hover output, definition output, and whether the adapter has source-comment fallback support.
ready: the language service can provide useful documentation.missingDependency: a recommended extension is not installed or enabled.degraded: the language service is present, but hover or definition output is not currently useful enough.unknown: Comment Lens cannot determine the current language-service state.
For missingDependency, install or enable the listed recommended extension. For degraded, put the cursor on a documented symbol and ensure the project has finished indexing.
Settings
| Setting |
Purpose |
commentLens.enabled |
Enable Comment Lens. |
commentLens.languages |
Registered adapter languages where Comment Lens runs. |
commentLens.languageOverrides |
Enable or disable Comment Lens per language. |
commentLens.maxHintsPerRequest |
Limit hints produced for one inlay-hint request. |
commentLens.maxLineLength |
Skip long generated or minified lines. |
commentLens.maxHintLength |
Limit the visible summary length. |
commentLens.minimumDocumentationWords |
Suppress very short low-signal summaries. |
commentLens.minIdentifierLength |
Ignore very short identifiers unless documentation has a definition location. |
commentLens.preferPropertyTail |
Prefer the final identifier in property chains such as foo.bar.baz. |
commentLens.dedupeLineHints |
Deduplicate repeated summaries on the same line. |
commentLens.resolveTimeoutMs |
Bound each documentation lookup. |
commentLens.maxCacheEntries |
Bound resolver cache growth. |
commentLens.hintPrefix |
Customize the displayed prefix before summaries. |
commentLens.enableHintInteractions |
Opt into inlay-hint tooltips and definition locations. |
Known Limits
Comment Lens only runs for file documents in registered adapter languages enabled by configuration. Coverage and wording depend on each language service's hover and definition providers.
When hover has no usable documentation, adapters with source fallback can read leading source comments near the definition. Timeout handling prevents stale hints from being displayed, but VS Code command calls already in flight cannot be forcibly cancelled by the extension.
Development
npm install
npm run compile
npm test
Before publishing, run:
npm run compile
npm test
npm run package
Run npm run test:integration when the local VS Code/Electron host is available.
Links
