Writing Style Checker

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

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",
  "ignore": ["CHANGELOG.md", "docs/vendor/**"],
  "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.

ignore is an array of glob patterns relative to the working directory. The GitHub Action uses the repository root. The CLI adds these patterns to its built-in **/node_modules/** and **/.git/** skips, together with the Action exclude input and the CLI --ignore flag.

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.

Tools

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.

npx wsc-mcp

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.

# Check all markdown files
npx wsc-lint check "**/*.md"

# Read from stdin
echo "The code was written very quickly." | npx wsc-lint check --stdin

# JSON output for scripting
npx wsc-lint check "**/*.md" --format json

# GitHub Actions annotations
npx wsc-lint check "**/*.md" --format github

# Create a config file
npx wsc-lint init

See the wsc-lint README for full documentation.

GitHub Action

- uses: theserverlessdev/wsc@v1
  with:
    files: '**/*.md'
    max-warnings: 20
    exclude: |
      CHANGELOG.md
      vendor/**

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

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

• Matt Might for the original shell scripts
• Built with SvelteKit and Svelte 5, deployed on Cloudflare Workers
• Logo made with DiffusionBee

License

MIT