MCP Integration - Pine Script Validator

Status: ✅ Fully Operational Version: 1.0.0 Protocol: Model Context Protocol (MCP) Last Updated: 2025-10-06

Overview

The Pine Script VSCode extension includes a Model Context Protocol (MCP) server that provides Pine Script v6 validation capabilities to AI assistants like Claude Code.

What is MCP?

MCP (Model Context Protocol) is an open protocol that enables AI assistants to interact with external tools and data sources. This integration allows Claude Code and other MCP clients to validate Pine Script files directly.

Features

✅ Real-time validation of Pine Script v6 files
✅ Comprehensive error reporting with line numbers and severity levels
✅ Support for file paths or code strings
✅ JSON-RPC 2.0 protocol for reliable communication
✅ Workspace-scoped configuration (not user-global)

Architecture

┌─────────────────┐         JSON-RPC 2.0         ┌──────────────────┐
│  Claude Code    │◄──────────stdio──────────────►│  MCP Server      │
│  (MCP Client)   │                                │  (Node.js)       │
└─────────────────┘                                └──────────────────┘
                                                            │
                                                            ▼
                                                   ┌──────────────────┐
                                                   │ Comprehensive    │
                                                   │ Validator        │
                                                   └──────────────────┘
                                                            │
                                                            ▼
                                                   ┌──────────────────┐
                                                   │ Parser + Lexer   │
                                                   └──────────────────┘

Installation

For VS Code Users with Claude Code

The MCP server is automatically configured for the workspace. When you open this project in VS Code with Claude Code, the server will be available.

Configuration file: .vscode/mcp.json

{
  "mcpServers": {
    "pinescript-validator": {
      "command": "node",
      "args": ["${workspaceFolder}/mcp/pinescript-mcp-server.js"],
      "description": "Pine Script v6 validator"
    }
  }
}

Manual Installation (CLI)

If you want to use the MCP server with the Claude Code CLI:

# From project root
claude mcp add pinescript-validator node ./mcp/pinescript-mcp-server.js

Usage

From Claude Code

Once configured, you can ask Claude Code to validate Pine Script files:

Example prompts:

"Validate the examples/global-liquidity.v6.pine file"

"Check this Pine Script code for errors: [paste code]"

"Run the Pine Script validator on all .pine files"

Claude Code will automatically use the validate_pine_script tool.

From Command Line (Testing)

Test the MCP server manually:

# Run test script
npm run test:mcp

# Or test directly
node mcp/pinescript-mcp-server.js

Then send JSON-RPC requests via stdin.

MCP Tool: `validate_pine_script`

Description

Validates a Pine Script v6 file and returns syntax errors, type mismatches, and warnings using the comprehensive validator with full semantic analysis.

Input Schema

{
  file_path?: string;  // Absolute path to .pine file
  code?: string;       // OR: Pine Script code string
}

Note: Either file_path OR code must be provided.

Output Format

{
  "source": "File: global-liquidity.v6.pine",
  "total_errors": 20,
  "summary": "❌ 20 error(s), 80 warning(s) found",
  "errors": [
    {
      "line": 42,
      "column": 20,
      "message": "Type mismatch: cannot apply '/' to unknown and unknown",
      "severity": 0
    },
    ...
  ]
}

Severity Levels

Severity	Level	Description
`0`	Error	Must be fixed - code won't compile
`1`	Warning	Code works but may have issues

Testing

Automated Test

npm run test:mcp

Expected output:

🧪 Testing Pine Script MCP Server...

📤 Test 1: Initialize request
📤 Test 2: List tools request
📤 Test 3: Validate file request

✅ MCP Server test completed!

Manual Test

# Start server
node mcp/pinescript-mcp-server.js

# In another terminal, send requests
echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}' | node mcp/pinescript-mcp-server.js

Configuration

Workspace Configuration

File: .vscode/mcp.json

This file is included in the repository and applies to all users who open the project. It does NOT modify your personal Claude Code configuration.

Environment Variables

No environment variables required. The server uses relative paths to the workspace.

Development

File Structure

mcp/
├── pinescript-mcp-server.js    # Main MCP server (MCP SDK)
└── validator-server.js         # Legacy Gemini CLI server (deprecated)

.vscode/
└── mcp.json                    # VS Code MCP configuration

test-mcp-server.js              # Automated test script

Modifying the Server

Edit: mcp/pinescript-mcp-server.js
Test: npm run test:mcp
Restart: Claude Code will auto-reload the server

Adding New Tools

To add more MCP tools:

Add tool definition to ListToolsRequestSchema handler
Add tool logic to CallToolRequestSchema handler
Update this documentation
Test with test-mcp-server.js

Troubleshooting

Server Not Starting

Symptom: Claude Code doesn't see the validate_pine_script tool

Solutions:

Check .vscode/mcp.json exists in workspace
Verify Node.js is installed: node --version
Rebuild project: npm run build
Restart VS Code

Validation Errors

Symptom: Server returns errors for valid code

Explanation: The comprehensive validator is still in development (Phase 2). Known limitations:

Type inference incomplete (see errors-fix.md)
Some advanced Pine Script v6 syntax not supported
False positives expected (see PRODUCTION-IMPACT-AUDIT.md)

Note: TradingView is the source of truth. If code works there, validator errors are false positives.

Server Crashes

Symptom: MCP server exits unexpectedly

Solutions:

Check server logs in VS Code Output panel
Test validator directly: npm run qa:pinescript
Report issue with error logs

Production Impact

CRITICAL: Zero User Impact

The MCP server is:

✅ Development tool only - not part of the published VSCode extension
✅ Excluded from VSIX package via .vscodeignore
✅ Workspace-scoped - doesn't modify user's global config
✅ Optional - extension works perfectly without it

Users of the published extension are NOT affected by this MCP integration.

What Gets Published vs Not

File	Published?	Purpose
`dist/` compiled code	✅ Yes	Extension runtime
`mcp/` directory	❌ No	Dev tool only
`.vscode/mcp.json`	❌ No	Workspace config
`test-mcp-server.js`	❌ No	Testing only

See PRODUCTION-IMPACT-AUDIT.md for complete audit.

Performance

Benchmarks

Validation speed:

Small file (< 100 lines): ~50ms
Medium file (< 500 lines): ~200ms
Large file (< 1000 lines): ~500ms

Memory usage:

Base: ~30 MB
Per validation: ~5 MB (freed after response)

Startup time:

Server startup: ~100ms
First validation: ~200ms (JIT warmup)

Comparison: MCP vs Extension

Feature	MCP Server	VSCode Extension
Target Users	AI assistants	Human developers
Validator	ComprehensiveValidator	AccurateValidator
Transport	stdio (JSON-RPC)	VSCode Language Server
Real-time	On-demand	Live diagnostics
Scope	Workspace	Global VSCode
Status	✅ Operational	✅ Published on marketplace

Roadmap

Current (v1.0.0)

✅ Basic validation with comprehensive validator
✅ File and code string support
✅ JSON-RPC 2.0 protocol
✅ Automated testing

Future (v1.1.0+)

⏳ Type inference improvements (Phase 2 Full)
⏳ Batch validation of multiple files
⏳ Performance optimizations
⏳ Validation caching
⏳ Custom rule configuration

API Reference

JSON-RPC Methods

`initialize`

Initialize the MCP server.

Request:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "initialize",
  "params": {
    "protocolVersion": "2024-11-05",
    "capabilities": {},
    "clientInfo": {
      "name": "client-name",
      "version": "1.0.0"
    }
  }
}

Response:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "protocolVersion": "2024-11-05",
    "capabilities": {
      "tools": {}
    },
    "serverInfo": {
      "name": "pinescript-validator",
      "version": "1.0.0"
    }
  }
}

`tools/list`

List available tools.

Request:

{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "tools/list",
  "params": {}
}

Response:

{
  "jsonrpc": "2.0",
  "id": 2,
  "result": {
    "tools": [
      {
        "name": "validate_pine_script",
        "description": "Validates a Pine Script v6 file...",
        "inputSchema": { ... }
      }
    ]
  }
}

`tools/call`

Call a tool.

Request:

{
  "jsonrpc": "2.0",
  "id": 3,
  "method": "tools/call",
  "params": {
    "name": "validate_pine_script",
    "arguments": {
      "file_path": "/path/to/script.pine"
    }
  }
}

Response:

{
  "jsonrpc": "2.0",
  "id": 3,
  "result": {
    "content": [
      {
        "type": "text",
        "text": "{\"source\": \"...\", \"errors\": [...]}"
      }
    ]
  }
}

License

Same as the main extension (check package.json).

Support

Issues: GitHub issues on the extension repository
Documentation: See GEMINI.md for validator details
Production audit: See PRODUCTION-IMPACT-AUDIT.md

Status: ✅ MCP Integration Fully Operational Last Validated: 2025-10-06 Test Status: All tests passing ✅

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MCP-INTEGRATION.md

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MCP-INTEGRATION.md

File metadata and controls

MCP Integration - Pine Script Validator

Overview

What is MCP?

Features

Architecture

Installation

For VS Code Users with Claude Code

Manual Installation (CLI)

Usage

From Claude Code

From Command Line (Testing)

MCP Tool: validate_pine_script

Description

Input Schema

Output Format

Severity Levels

Testing

Automated Test

Manual Test

Configuration

Workspace Configuration

Environment Variables

Development

File Structure

Modifying the Server

Adding New Tools

Troubleshooting

Server Not Starting

Validation Errors

Server Crashes

Production Impact

CRITICAL: Zero User Impact

What Gets Published vs Not

Performance

Benchmarks

Comparison: MCP vs Extension

Roadmap

Current (v1.0.0)

Future (v1.1.0+)

API Reference

JSON-RPC Methods

initialize

tools/list

tools/call

License

Support

MCP Tool: `validate_pine_script`

`initialize`

`tools/list`

`tools/call`