Writing Style Checker
A prose linter and AI-slop detector. WSC finds AI tells — words, phrases, and sentence structures overrepresented in AI-generated text, each flag backed by a published corpus study. It also catches classic writing issues: weasel words, passive voice, duplicate words, long sentences, nominalizations, hedging, and filler adverbs. Available as a web editor, HTTP API, MCP server, CLI, and GitHub Action.
Live: wsc.theserverless.dev
Features
- Web Editor - Real-time highlighting with inline fix buttons for all 8 detectors
- HTTP API - POST text with optional config, retrieve structured JSON responses
- MCP Server (Remote) - Connect AI assistants via Streamable HTTP transport
- MCP Server (Local) - Stdio-based server via
wsc-mcp on npm
- CLI - Check files from the command line via
wsc-lint
- GitHub Action - Run checks in CI with
::warning annotations
- Configurable - Customize detectors with
.wscrc.json files
What WSC is (and isn't)
WSC flags patterns that research on AI-generated text finds overrepresented, and cites a source for every flag. It does not, and cannot, prove authorship. Classifier-based detectors carry a documented false-accusation risk: a Stanford study found that seven of them misflagged 61% of essays written by non-native English speakers. WSC avoids that trap by design — every flag is a specific, explainable edit that improves the text no matter who, or what, wrote it.
Detection Rules
| Detector | Items | Description |
|---|
| Weasel Words | 95 words/phrases | Vague terms like "very", "basically", "arguably", "numerous" |
| Passive Voice | 260 irregular verbs | Auxiliary verbs + past participles (regular -ed + irregular) |
| Duplicate Words | — | Adjacent repeated words across whitespace, case-insensitive |
| Long Sentences | threshold: 30 words | Sentences exceeding a configurable word count |
| Nominalizations | 245 word pairs | Nouns replaceable with verbs ("utilization" → "use") |
| Hedging | 100 phrases | Phrases that weaken assertions ("I think", "it seems") |
| Filler Adverbs | 139 words | Adverbs adding emphasis without substance ("totally", "utterly") |
| AI Tells | 98 words (+111 inflected forms) + 83 phrases + 12 structural patterns | Words, phrases, and sentence constructions overrepresented in AI-generated text (delve, rich tapestry, It's not just X — it's Y) |
Word lists sourced from Matt Might's shell scripts and expanded with additional entries. AI tells draw on published corpus studies: Kobak et al. 2025 (Science Advances), Juzek & Ward 2025 (COLING), Liang et al. 2024 (Stanford), and Reinhart et al. 2025 (PNAS). Wikipedia's editor-maintained Signs of AI writing catalogue and AI-detection vendor reports round out the sources.
Configuration
Create a .wscrc.json to customize detectors. All tools (API, MCP, CLI) support it.
{
"$schema": "https://wsc.theserverless.dev/schema.json",
"detectors": {
"weaselWords": {
"enabled": true,
"add": ["synergy", "leverage"],
"remove": ["very"]
},
"longSentences": { "maxWords": 25 },
"adverbs": { "enabled": false }
}
}
Every field is optional. Missing fields use defaults. JSON Schema provides autocompletion in VS Code.
API Usage
POST /api/check
Analyze text for writing style issues. Accepts optional config object.
curl -X POST https://wsc.theserverless.dev/api/check \
-H "Content-Type: application/json" \
-d '{"text":"The code was written very quickly."}'
Response:
{
"summary": {
"total": 2,
"weaselWords": 1,
"passiveVoice": 1,
"duplicateWords": 0,
"longSentences": 0,
"nominalizations": 0,
"hedging": 0,
"adverbs": 0
},
"issues": {
"weaselWords": [{ "word": "very", "index": 21, "line": 1, "column": 22, "context": "..." }],
"passiveVoice": [{ "phrase": "was written", "index": 9, "line": 1, "column": 10, "context": "..." }],
"duplicateWords": [],
"longSentences": [],
"nominalizations": [],
"hedging": [],
"adverbs": []
},
"meta": { "characterCount": 34, "wordCount": 6, "sentenceCount": 1, "processingTimeMs": 2 }
}
With config:
curl -X POST https://wsc.theserverless.dev/api/check \
-H "Content-Type: application/json" \
-d '{"text":"The code was written very quickly.", "config":{"detectors":{"weaselWords":{"enabled":false}}}}'
GET /api/check
Returns API documentation as JSON.
GET /api/detectors
Returns the list of all 8 detectors with descriptions, configurability, and word counts.
GET /health
Runs a smoke test with known text and returns {"status":"healthy"} or 503.
Limits: Max 100,000 characters per request. CORS enabled for all origins.
MCP Server
The Writing Style Checker is available as an MCP server, letting AI assistants check your writing directly.
| Tool | Description |
|---|
check_text | Analyze text for all 8 writing style issues. Accepts optional config. |
fix_duplicates | Remove duplicate adjacent words and return cleaned text |
list_word_lists | Return info about all detector word lists |
check_file | (Local only) Read a file from disk and analyze it. Auto-discovers .wscrc.json. |
Remote MCP Server
Connect any MCP client to the hosted server - no installation required.
{
"mcpServers": {
"writing-style-checker": {
"type": "url",
"url": "https://wsc.theserverless.dev/mcp"
}
}
}
Local MCP Server (stdio)
Install via npm for local usage. Includes check_file for analyzing files on disk with auto-discovery of .wscrc.json.
Claude Desktop / Claude Code config:
{
"mcpServers": {
"writing-style-checker": {
"command": "npx",
"args": ["wsc-mcp"]
}
}
}
See the wsc-mcp npm page for full documentation.
CLI
Check files from the command line.
npx wsc-lint check "**/*.md"
echo "The code was written very quickly." | npx wsc-lint check --stdin
npx wsc-lint check "**/*.md" --format json
npx wsc-lint check "**/*.md" --format github
npx wsc-lint init
See the wsc-lint README for full documentation.
GitHub Action
- uses: theserverlessdev/wsc@v1
with:
files: '**/*.md'
max-warnings: 20
| Input | Default | Description |
|---|
files | **/*.md | Glob pattern for files to check |
config | — | Path to .wscrc.json config file |
max-warnings | unlimited | Max warnings before failing |
only-changed | false | Only check files changed in this PR |
Privacy
The web editor runs in your browser - we never send text to any server. The API and MCP endpoints only process text you explicitly send to them.
Project Structure
.
├── src/
│ ├── core/ # Shared detection engine
│ │ ├── detector.ts # 8 detection algorithms
│ │ ├── words.ts # Word/phrase lists (800+ entries)
│ │ ├── config.ts # Config types, merging, validation
│ │ ├── config-node.ts # Node-only: file loading, discovery
│ │ ├── analyzer.ts # Unified analyzeText() entry point
│ │ └── index.ts # Public API exports
│ ├── docs/ # Documentation content (Markdown files)
│ ├── mcp/
│ │ └── handler.ts # MCP JSON-RPC 2.0 handler
│ ├── lib/
│ │ ├── App.svelte # Main editor page component
│ │ ├── stores/theme.ts # Theme store (light/dark/system)
│ │ └── components/ # UI components (StatsBar, ConfigPanel, etc.)
│ ├── routes/
│ │ ├── +layout.svelte # Shared layout (header, nav, footer)
│ │ ├── api/check/+server.ts # HTTP API endpoint
│ │ ├── mcp/+server.ts # MCP endpoint
│ │ ├── health/+server.ts # Health check endpoint
│ │ ├── docs/+page.svelte # Documentation page
│ │ └── words/+page.svelte # Word library browser
│ └── styles/
│ └── main.scss # Global styles (light + dark themes)
├── mcp-server/ # Standalone stdio MCP server (npm: wsc-mcp)
├── cli/ # CLI tool (npm: wsc-lint)
├── action/ # GitHub Action (composite)
├── tests/ # 341 tests across 18 files
├── static/
│ ├── schema.json # JSON Schema for .wscrc.json
│ ├── llms.txt # AI/LLM discovery file
│ └── llms-full.txt # Detailed LLM context
├── wrangler.toml # Cloudflare Workers config
└── svelte.config.js # SvelteKit configuration
Local Development
git clone https://github.com/theserverlessdev/wsc.git
cd wsc
npm install
npm run dev
Visit http://localhost:5173. The API is at /api/check, MCP at /mcp, health at /health.
Commands
| Command | Description |
|---|
npm run dev | Start dev server |
npm run build | Build for production |
npm run check | Type check with svelte-check |
npm test | Run all 341 tests |
npm run test:coverage | Coverage report |
Deployment
Deployed as a Cloudflare Worker at wsc.theserverless.dev.
npm run build
npx wrangler deploy
Contributing
See CONTRIBUTING.md for development setup, testing, and pull request guidelines.
For substantial changes, please open an issue first.
Acknowledgements
License
MIT