mcp-code-context

MCP server with Tree-sitter WASM parsers for 100% AST accuracy. Zero native dependencies. Production-ready with persistent caching, structured logging, fuzzy search, multi-process safety, and session-scoped state.

🚀 Quick Start (Claude Desktop)

1. Install: npm install -g mcp-code-context

2. Configure: Add to claude_desktop_config.json:

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

3. Enjoy: Use symbols like @code-context to map repos or edit code surgically.

No build tools required - Works on Windows/Mac/Linux without Visual Studio, Python, or node-gyp.

Works with Claude Desktop, Cursor, Windsurf, GitHub Copilot, Amazon Q, and any Model Context Protocol compatible client.

📖 For AI Agents: See INSTRUCTIONS.md for essential usage patterns and best practices.

Related MCP server: Semantic Cache MCP

💡 Why This Exists

This tool was born out of necessity in Caracas, Venezuela 🇻🇪, where economic limitations made every API token count. When you're choosing between groceries and Claude API credits, you learn to optimize fast.

What started as a personal script to compress context windows became a full MCP server when I realized others faced the same problem: LLM APIs are expensive, and most tools waste tokens on boilerplate.

If this tool saves you money or time, consider supporting its development. Every contribution helps keep this project maintained and free for everyone.

The Problem

LLMs working with code face two bottlenecks:

1. Reading: Sending raw source files wastes the context window on function bodies and boilerplate. A 500-line file might contain only 30 lines of structural information the LLM needs.

2. Writing: Rewriting entire files to change one function is error-prone, token-expensive, and risks corrupting unrelated code.

The Solution

mcp-code-context provides 25 tools — covering reading, writing, AST transformation, search, and session management — all operating at the symbol level (functions, classes, methods). Tools support a className scope to correctly isolate identical symbol names in the same file (e.g. Flutter build() methods). Read tools extract structural skeletons. Write tools splice changes into the exact AST location.

Token Savings

Real-world results:

• TypeScript project: 73% reduction in tokens sent to LLM

• PHP application: 82% reduction

• Dart codebase: 79% reduction

Reliability & Testing

Built to be robust and precise. Both read and write engines are tested against real-world, complex codebases (including nested generic types in Dart, complex interfaces in PHP, and multi-file rename operations) with a 100% test pass rate across all languages and operations.

Production-Ready Features

Features

What's New in v3.9.1

Previous: v3.9.0

Previous: v3.8.0

Previous Versions (v3.6.x)

Read

• 🌳 AST-based compression — Real Tree-sitter WASM parsers for TypeScript/JavaScript/Python/PHP/Dart. Zero regex-based parsing.

• 🔬 Surgical symbol extraction — Extract a single function, class, or method from a file by name. Use className to scope disambiguation (e.g., getting multiple build() methods in Dart).

• 💥 Impact analysis — Discover all files that depend on a given file before refactoring. Supports ES imports, CommonJS require(), Python imports, PHP use/require_once/include, and Dart imports.

• 📁 Smart file walking — Respects .gitignore and .repomixignore rules. Automatically excludes node_modules, dist, vendor, .git, etc.

• 📄 Multi-format output — XML (optimized for LLM consumption) or Markdown (human-readable).

Write

• ✏️ Surgical symbol replacement — Replace a function, method, or class body without touching the rest of the file. Narrow down the target using the className parameter.

• ➕ Precise code insertion — Insert new code before/after a symbol, or inside a class at the start/end.

• 🔄 Repository-wide rename — Rename a symbol in its definition AND all files that import it, atomically.

• 🗑️ Safe symbol removal — Delete code with automatic dependency checking to prevent breakage.

• 🔍 Mandatory dry-run flow — Write tools return a preview diff and a confirmationToken by default. Changes are only applied after explicit confirmation.

• 💾 Robust rolling backups — Automatically keeps the last 5 versions of modified files in the OS temp directory.

• ⏪ Surgical rollback — Revert files to any of the 5 previous states using the rollback_file tool.

• ���� Fuzzy symbol matching — When a symbol is not found, the server provides structured suggestions based on Levenshtein distance.

• 🔐 Private symbol support — Full support for _ and __ prefixed symbols in Dart and Python.

Supported Languages

⚠️ Known Limitations

rename_symbol Tool

All languages: The definition file is renamed using AST (Tree-sitter) — safe and precise. ✅

Cross-file rename (dependent files): Updated using regex word-boundaries for all languages, including TypeScript, JavaScript, and PHP.

• Risk: Regex may match strings, comments, or unrelated identifiers sharing the same name

• Dart and Python: Higher risk — import syntax (import 'package:...', from module import name) is less reliably matched by the current regex patterns

• Recommendation: Always review the generated diff carefully before confirming

• Alternative: Use write_file_surgical to rename within a single file safely

get_semantic_repo_map Tool

• Max files: Limited to 2000 files to prevent timeouts (increased from 500 in v3.9.1)

• Performance: Synchronous I/O may take 10-30 seconds on large repositories

• Recommendation: Use @folder syntax to target specific directories

General

• Validation: No automatic syntax checking after edits. Always review diffs carefully before confirming.

• Backups: 5-version rolling backup system. Use rollback_file if something goes wrong.

• Large files: Files >10MB are skipped for safety.

• Phase 2 tokens: Confirmation tokens expire after 5 minutes.

Installation

# Global installation (recommended)
npm install -g mcp-code-context

# Or use directly with npx (no installation)
npx -y mcp-code-context

Note: Unlike v2.x, this version uses web-tree-sitter (WASM) instead of native bindings. No Visual Studio, Python, or node-gyp required!

Session State (v3.9.1+)

Important: v3.9.1 introduces session-scoped state for each MCP client connection. This prevents state leakage when multiple agents (Amazon Q, Kiro, Cursor, etc.) use the same server instance.

What Changed

Benefits

• ✅ No state leakage: Each agent gets isolated locks, confirmation store, and rate limiter

• ✅ Crash recovery: Pending operations survive server restarts

• ✅ Multi-agent safe: Amazon Q and Kiro can run simultaneously without conflicts

Configuration

No additional configuration needed. Session isolation is automatic. Just configure your MCP server normally:

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

Ruby Intelligence Tools (v3.9.x)

• get_gemfile_context — Parse Gemfile, get implicit gem behaviors (devise, sidekiq, pundit, etc.)

• find_metaprogramming — Scan for define_method, method_missing, class_eval, concerns, has_many :through

• get_rails_routes — Parse config/routes.rb into structured route map with namespace support

• get_session_stats — Get stats for current session only

• clear_session_cache — Clear cache for current session only

• list_pending_operations — List pending operations for recovery

Configuration

Claude Desktop

Add to your claude_desktop_config.json:

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

Cursor

Add to your Cursor MCP settings (.cursor/mcp.json):

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

Windsurf

Add to your Windsurf MCP config:

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

Amazon Q

Add to your Amazon Q MCP config:

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

Kiro

Add to your Kiro MCP config (.kiro/settings/mcp.json):

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

Antigravity

Add to your Antigravity MCP config (.antigravity/mcp.json):

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

Other MCP Clients

Any MCP-compatible client can use this server. The transport is stdio (JSON-RPC over stdin/stdout). Point your client to npx -y mcp-code-context.

Tools

Tool Reference (25 tools)

Read Tools

Write Tools (Two-Phase: preview → confirm)

All write tools require two calls:

1. Phase 1 — Call normally → returns diff + confirmationToken

2. Phase 2 — Call again with confirm: true + confirmationToken → applies changes

newContent/code are not required in Phase 2 — the server stores them from Phase 1.

Admin / Recovery Tools

Recommended Workflow

1. Understand → get_semantic_repo_map to see the architecture

2. Read → read_file_surgical with symbol name for specific implementations

3. Assess → analyze_impact before modifying shared files

4. Edit (Preview) → Call write tools to generate a diff and confirmationToken

5. Confirm → Call the same write tool with the token and confirm: true to apply

6. Recovery → Use rollback_file if something goes wrong after confirmation

💰 Support This Project

Why Support?

This tool was born in Caracas, Venezuela 🇻🇪, where economic limitations mean every API token counts. What started as a personal script to save money on Claude API became a full MCP server when I realized others faced the same problem.

Current Reality:

• ⏰ ~10 hours/week of maintenance

• 💵 ~$20/month in costs (npm, testing, domain)

• 🆓 100% free and open source (always will be)

If this tool saves you time or money, consider supporting its development.

💳 Ways to Support

🔹 One-Time Donation

Ko-fi (PayPal + Cards, 0% fees)
ko-fi.com/achatainga

PayPal (Direct)
paypal.me/achatainga

Binance (USDT) (Crypto, lowest fees)

• TRC20/ERC20: 0xa68d53f7853ce0175eb96aaad4a30c068ca96444

• Binance Pay ID: 367669339

Recommended: TRC20 for lower gas fees

Suggested Amounts:

• ☕ $5 - A coffee (1 hour of development)

• 🍕 $25 - A pizza (testing a new language)

• 🚀 $100 - Rocket fuel (major feature development)

🔹 Recurring Support

Ko-fi Membership
ko-fi.com/achatainga/tiers

Monthly tiers:

• $5/month - Supporter (name in SPONSORS.md)

• $25/month - Contributor (priority support, early access)

• $100/month - Sponsor (feature requests, 1-on-1 consultation)

🔹 Hire Me

Need custom MCP tools or AI integrations?

• 💼 Available for: Freelance contracts

• 🌐 Location: Caracas, Venezuela (Remote)

• 💻 Skills: TypeScript, Node.js, MCP, AI/LLM integrations

• 💵 Rate: $50-75/hour

📧 Contact: a.chataing.a@gmail.com
📄 Details: HIRE_ME.md

📊 Transparency

I believe in radical transparency:

Current Status:

• 💰 Donations received: $0

• 💸 Expenses: $20/month (npm, testing)

• ⏰ Time invested: ~10 hours/week

• 📦 Downloads: 10,000+/month

(Updated monthly)

🏆 Hall of Fame

Thank you to these amazing supporters:

(No sponsors yet - be the first!)

See full list: SPONSORS.md

❤️ Non-Financial Support

Can't donate? No problem! You can still help:

• ⭐ Star the repo on GitHub

• 🐛 Report bugs or suggest features

• 📝 Improve documentation

• 🗣️ Share with others who might benefit

• 💬 Join discussions and help other users

Every contribution matters, financial or not.

Development

# Build
npm run build

# Run tests
npm test

# Development (build + start)
npm run dev

Technical Details

• Transport: stdio (JSON-RPC over stdin/stdout)

• Runtime: Node.js >= 18

• Protocol: Model Context Protocol

• AST Engines: web-tree-sitter@0.25.1 (WASM) for TypeScript/JS/Python/PHP/Dart

• Language Grammars: tree-sitter-wasms@0.1.13 (ABI v15)

• Cache: sql.js@1.14.1 (WASM SQLite, zero native deps)

• Logging: pino@10.3.1 (JSON to stderr, MCP-safe)

• File Watcher: chokidar@5.0.0 (auto cache invalidation)

• Fuzzy Search: fuse.js@7.3.0 (typo-tolerant matching)

• File Locking: proper-lockfile@4.1.2 (multi-process safe, OS temp)

• Diff: diff-match-patch@1.0.5 (Myers algorithm, O(n+d²))

• Ignore Engine: ignore npm package (full .gitignore spec support)

• Safety Features: Mandatory two-phase confirmation, rolling 5-version backups, fuzzy matching, dependency checking, surgical restoration, ReDoS protection via worker_threads, session-scoped state.

• Portability: 100% WASM - no native dependencies, works on all platforms

• Tests: 83 passing (unit + integration + performance + stress)

v3.9.1 Key Changes

Contributing

See CONTRIBUTING.md for guidelines.

Security

See SECURITY.md for security policies and reporting vulnerabilities.

Troubleshooting

See TROUBLESHOOTING.md for common issues and solutions.

Viewing Logs

Because MCP uses stdout for protocol communication, all logs are safely routed to stderr. You can view them in your client's log files:

• Claude Desktop (macOS): ~/Library/Logs/Claude/mcp-server-mcp-code-context.log

• Claude Desktop (Windows): %APPDATA%\Claude\logs\mcp-server-mcp-code-context.log

• Cursor: Output panel → Select mcp-code-context from the dropdown

• Amazon Q: Check stderr output in the MCP server configuration

• Kiro: Check logs in the MCP server view

• Antigravity: Check logs in the MCP server view

Environment Variables (optional):

{
  "mcpServers": {
    "mcp-code-context": {
      "command": "npx",
      "args": ["-y", "mcp-code-context"],
      "env": {
        "NODE_ENV": "development",
        "LOG_LEVEL": "debug"
      }
    }
  }
}

Supported LOG_LEVEL values: fatal, error, warn, info, debug, trace (default: info).

Changelog

See CHANGELOG.md for version history.

License

MIT

Built with ❤️ from Caracas, Venezuela 🇻🇪