CodeSentinel MCP Server

A comprehensive code quality analysis server for the Model Context Protocol (MCP). CodeSentinel integrates with Claude Code and other MCP-compatible clients to detect security vulnerabilities, deceptive patterns, incomplete code, and highlight good practices.

Why CodeSentinel?

AI coding assistants can inadvertently introduce subtle issues: hardcoded secrets, empty catch blocks, TODO placeholders left behind, or patterns that hide errors. CodeSentinel acts as a quality gate, analyzing code for 93 distinct patterns across 5 categories before issues reach production.

Key differentiators:

• Verification-aware detection: Many patterns include verification steps to reduce false positives
• LLM-optimized output: Structured JSON output designed for AI consumption and action
• Balanced analysis: Detects both issues AND strengths for fair code assessment
• Multi-language support: Works with TypeScript, JavaScript, Python, Go, Rust, Java, and more

Features

• Security Analysis (16 patterns): Hardcoded secrets, SQL injection, XSS, command injection, insecure crypto, disabled SSL, and more
• Deceptive Pattern Detection (17 patterns): Empty catch blocks, silent failures, error-hiding fallbacks, linter suppression
• Placeholder Detection (19 patterns): TODO/FIXME/HACK comments, lorem ipsum, test data, incomplete implementations
• Error & Code Smell Detection (18 patterns): Type coercion issues, null references, async anti-patterns, floating point comparison
• Strength Recognition (23 patterns): Highlights good practices like proper typing, error handling, testing patterns, documentation
• HTML Reports: Visual reports with quality scores and actionable suggestions

Installation

From npm

npm install -g code-sentinel-mcp

From source

git clone https://github.com/your-username/code-sentinel.git
cd code-sentinel
npm install
npm run build

Usage with Claude Code

Quick setup

claude mcp add code-sentinel -- npx code-sentinel-mcp

Or if installed globally

claude mcp add code-sentinel -- code-sentinel

Manual configuration

Add to your Claude Code MCP configuration file (~/.claude/claude_desktop_config.json):

{
  "mcpServers": {
    "code-sentinel": {
      "command": "npx",
      "args": ["code-sentinel-mcp"]
    }
  }
}

Available Tools

analyze_code

Full analysis returning structured JSON with all issues and strengths. Best for programmatic processing.

Parameters:

• code (string, required): The source code to analyze
• filename (string, required): Filename for language detection (e.g., "app.ts")

Returns: JSON object with issues, strengths, and summary statistics.

generate_report

Full analysis with a visual HTML report. Best for human review.

Parameters:

• code (string, required): The source code to analyze
• filename (string, required): Filename for language detection

Returns: Markdown summary plus complete HTML report.

check_security

Security-focused analysis only. Use when you specifically want to audit for vulnerabilities.

Parameters:

• code (string, required): The source code to check
• filename (string, required): Filename

Returns: List of security issues or confirmation of none found.

check_deceptive_patterns

Check for code patterns that hide errors or create false confidence.

Parameters:

• code (string, required): The source code to check
• filename (string, required): Filename

Returns: List of deceptive patterns found.

check_placeholders

Find TODOs, dummy data, and incomplete implementations.

Parameters:

• code (string, required): The source code to check
• filename (string, required): Filename

Returns: List of placeholder code found.

analyze_patterns

Analyze code for architectural, design, and implementation patterns. Detects pattern usage, inconsistencies, and provides actionable suggestions.

Parameters:

• code (string, required): The source code to analyze
• filename (string, required): Filename for language detection
• level (string, optional): Pattern level to analyze:
  • architectural: System structure patterns (layering, modules)
  • design: Gang of Four patterns (Singleton, Factory, Observer)
  • code: Implementation idioms (error handling, async patterns)
  • all: All levels (default)
• query (string, optional): Natural language query to focus analysis (e.g., "how is error handling done?")

Returns: LLM-optimized JSON with detected patterns, inconsistencies, suggestions, and ready-to-execute action items.

analyze_design_patterns

Focused analysis of Gang of Four (GoF) design patterns. Best for understanding OOP structure.

Parameters:

• code (string, required): The source code to analyze
• filename (string, required): Filename for language detection

Returns: Detected design patterns with confidence levels, locations, and implementation details.

Example Usage

Ask Claude to analyze code:

Analyze this code for quality issues:

const API_KEY = "sk-abc123456789";

async function fetchData() {
  try {
    const response = await fetch(url);
    return response.json();
  } catch (e) {
    // TODO: handle error
  }
}

CodeSentinel will detect:

• Critical (CS-SEC003): OpenAI API key hardcoded in source
• High (CS-DEC001): Empty catch block silently swallowing errors
• Low (CS-PH001): TODO comment indicating incomplete implementation

Detection Categories

Security Issues (CS-SEC)

ID	Pattern
SEC001	Hardcoded secrets (API keys, tokens, passwords)
SEC002	GitHub tokens
SEC003	OpenAI API keys
SEC004	AWS access keys
SEC005-010	SQL injection patterns
SEC011-015	XSS vulnerabilities
SEC016	Command injection (eval, exec)

Deceptive Patterns (CS-DEC)

ID	Pattern
DEC001-003	Empty/comment-only catch blocks
DEC010-012	Silent promise rejections
DEC020-025	Error-hiding fallbacks (
DEC030+	Linter suppression, fake success responses

Placeholders (CS-PH)

ID	Pattern
PH001-005	TODO/FIXME/HACK/XXX/NOTE comments
PH010-015	Lorem ipsum, placeholder text
PH020-025	Test/dummy data (test@example.com, password123)
PH030+	console.log debugging, debugger statements

Errors & Code Smells (CS-ERR)

ID	Pattern
ERR001-005	Loose equality (==), type coercion issues
ERR010-015	Null reference risks
ERR020-025	Async anti-patterns
ERR030+	parseInt without radix, array mutation in loops

Strengths (CS-STR)

ID	Pattern
STR001-005	TypeScript strict typing
STR010-015	Proper error handling patterns
STR020-025	Test coverage indicators
STR030+	Documentation, input validation

Scoring Algorithm

Quality score (0-100) calculated as:

Score = 100 - (critical × 25) - (high × 15) - (medium × 5) - (low × 1) + (strengths × 2)

Severity	Point Deduction
Critical	-25 points
High	-15 points
Medium	-5 points
Low	-1 point
Strength	+2 points (bonus)

Supported Languages

CodeSentinel detects language from file extensions:

Extension	Language
.ts, .tsx	TypeScript
.js, .jsx	JavaScript
.py	Python
.go	Go
.rs	Rust
.java	Java
.kt	Kotlin
.swift	Swift
.cs	C#
.cpp, .c	C/C++
.php	PHP
.vue	Vue
.svelte	Svelte

Extending CodeSentinel

Add custom patterns by editing files in src/analyzers/:

src/analyzers/
├── security.ts      # Security vulnerability patterns
├── deceptive.ts     # Error-hiding patterns
├── placeholders.ts  # Incomplete code patterns
├── errors.ts        # Code smell patterns
└── strengths.ts     # Good practice patterns

Each pattern follows this structure:

{
  id: 'CS-SEC001',           // Unique ID with category prefix
  pattern: /regex/g,          // RegExp to match
  title: 'Short description',
  description: 'Detailed explanation',
  severity: 'critical',       // critical | high | medium | low | info
  category: 'security',
  suggestion: 'How to fix',
  verification: {             // Optional: reduce false positives
    assumption: 'What we assume is true',
    confirmIf: 'When to confirm as real issue',
    falsePositiveIf: 'When to dismiss'
  }
}

Development

# Install dependencies
npm install

# Build
npm run build

# Watch mode
npm run watch

# Test with MCP inspector
npm run inspector

Contributing

Contributions welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Add patterns following the existing format
4. Submit a pull request

License

MIT

Links

• Model Context Protocol
• Claude Code
• npm package