Sandbox GSTR-1 MCP Server

![License: MIT](https://opensource.org/licenses/MIT) ![Python 3.11+](https://www.python.org/downloads/) ![MCP Protocol](https://modelcontextprotocol.io)

A powerful Model Context Protocol (MCP) server for automating GSTR-1 (Goods and Services Tax Return - 1) filing through the Sandbox.co APIs. Seamlessly integrate with Claude Desktop or Claude API to automate your GST return filing process.

🚀 Quick Start

For Claude Desktop Users

Clone the repository:

   git clone https://github.com/yourusername/sandbox-gstr1-mcp.git
   cd sandbox-gstr1-mcp

Install dependencies:

   pip install -r requirements.txt

Add to Claude Desktop:

Open your Claude Desktop configuration file:
macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json
Linux: ~/.config/Claude/claude_desktop_config.json

Add this configuration:

     {
       "mcpServers": {
         "sandbox-gstr1": {
           "command": "python",
           "args": ["/path/to/sandbox-gstr1-mcp/server.py"],
           "env": {
             "SANDBOX_API_KEY": "key_test_ed6b10d21cf546d7b4b600021f91c341",
             "SANDBOX_API_SECRET": "secret_test_798d3274325741fab93dd24bbb786a3a"
           }
         }
       }
     }

Restart Claude Desktop and start using the GSTR-1 filing tools!

For Developers

# Clone and setup
git clone https://github.com/yourusername/sandbox-gstr1-mcp.git
cd sandbox-gstr1-mcp

# Install dependencies
pip install -r requirements.txt

# Run the server
export SANDBOX_API_KEY="key_test_ed6b10d21cf546d7b4b600021f91c341"
python server.py

📋 Features

Complete GSTR-1 Filing Workflow

✅ Taxpayer Authentication: Generate and manage 6-hour sessions
✅ Data Submission: Save B2B, B2CL, B2CS, HSN, and document data
✅ Status Monitoring: Real-time filing status tracking
✅ Filing Initialization: Prepare returns for submission
✅ Summary Retrieval: Get section-wise summaries and checksums
✅ OTP Generation: Electronic Verification Code generation
✅ Return Filing: Submit final GSTR-1 with OTP verification
✅ Excel Conversion: Transform Excel output to API format

Supported GSTR-1 Sections

| Section | Type | Description | |---------|------|-------------| | B2B | Business-to-Business | Regular invoices to registered businesses | | B2CL | B2C Large | Large value B2C invoices (>₹1,00,000 from Aug 2024) | | B2CS | B2C Small | Aggregated B2C transactions | | HSN | Summary | Harmonized System of Nomenclature aggregation | | Credit Notes | Amendments | For refunds and adjustments | | Exports | International | Export transactions | | Amendments | Revisions | Amendments to previously filed returns |

🛠️ Available Tools

The MCP server exposes 8 powerful tools for GSTR-1 filing:

1. Generate Taxpayer Session

generate_taxpayer_session(gstin, username)

Creates a 6-hour valid taxpayer session token.

2. Save GSTR-1 Data

save_gstr1_data(access_token, gstin, ret_period, gstr1_data)

Uploads GSTR-1 data for validation.

3. Check Return Status

check_return_status(access_token, gstin, ret_period, reference_id)

Monitors filing operation status.

4. Proceed to File

proceed_to_file(access_token, gstin, ret_period, is_nil)

Initializes the filing process.

5. Get GSTR-1 Summary

get_gstr1_summary(access_token, gstin, ret_period, summary_type)

Retrieves section summaries and checksums.

6. Generate EVC OTP

generate_evc_otp(access_token, pan)

Generates Electronic Verification Code OTP.

7. File GSTR-1

file_gstr1(access_token, gstin, ret_period, pan, otp, sec_sum, chksum)

Submits the final GSTR-1 return.

8. Convert Excel to Sandbox Payload

convert_excel_to_sandbox_payload(excel_path)

Transforms Excel output to API format.

📖 Documentation

README.md - Comprehensive API documentation and workflow details
CONFIGURATION.md - Setup, configuration, and deployment guide
EXAMPLES.md - Practical code examples for various scenarios
CLAUDE_INTEGRATION.md - Claude Desktop and API integration guide

🔧 Configuration

Environment Variables

# Required
export SANDBOX_API_KEY="key_test_ed6b10d21cf546d7b4b600021f91c341"
export SANDBOX_API_SECRET="secret_test_798d3274325741fab93dd24bbb786a3a"

# Optional
export SANDBOX_API_URL="https://api.sandbox.co.in"
export SANDBOX_API_VERSION="1.0.0"
export LOG_LEVEL="INFO"

Test Credentials

The server comes pre-configured with test credentials that don't consume quota:

API Key: key_test_ed6b10d21cf546d7b4b600021f91c341
API Secret: secret_test_798d3274325741fab93dd24bbb786a3a
Environment: Test (safe for development)

📊 GSTR-1 Filing Workflow

┌─────────────────────────────────────────────────────────────┐
│  1. Generate Taxpayer Session (6-hour validity)             │
└────────────────────┬────────────────────────────────────────┘
                     │
┌────────────────────▼────────────────────────────────────────┐
│  2. Save GSTR-1 Data (B2B, B2CL, B2CS, HSN, etc.)          │
└────────────────────┬────────────────────────────────────────┘
                     │
┌────────────────────▼────────────────────────────────────────┐
│  3. Check Return Status (Poll until complete)               │
└────────────────────┬────────────────────────────────────────┘
                     │
┌────────────────────▼────────────────────────────────────────┐
│  4. Proceed to File (Initialize filing)                     │
└────────────────────┬────────────────────────────────────────┘
                     │
┌────────────────────▼────────────────────────────────────────┐
│  5. Get GSTR-1 Summary (Get checksums)                      │
└────────────────────┬────────────────────────────────────────┘
                     │
┌────────────────────▼────────────────────────────────────────┐
│  6. Generate EVC OTP (For verification)                     │
└────────────────────┬────────────────────────────────────────┘
                     │
┌────────────────────▼────────────────────────────────────────┐
│  7. File GSTR-1 (Submit with OTP)                           │
└────────────────────┬────────────────────────────────────────┘
                     │
                     ▼
            ✅ Filing Complete

🧪 Testing

Run the comprehensive test suite:

python test_server.py

Expected output: ``` ============================================================ Test Summary ============================================================ ✓ PASSED: Imports ✓ PASSED: API Endpoints ✓ PASSED: Payload Structure ✓ PASSED: Credentials ✓ PASSED: Workflow

Total: 5/5 tests passed ============================================================ ```

💬 Using with Claude

Claude Desktop

Once configured, use natural language:

"File a GSTR-1 return for GSTIN 29AAACQ3770E000 for March 2026"

"Generate a taxpayer session and save GSTR-1 data with B2B invoices"

"Check the status of my GSTR-1 filing with reference ID xyz123"

"Convert my GSTR-1 Excel file to the Sandbox API format"

Claude API

import anthropic

client = anthropic.Anthropic(api_key="your-api-key")

response = client.messages.create(
    model="claude-3-5-sonnet-20241022",
    max_tokens=1024,
    tools=[...],  # MCP tools
    messages=[
        {
            "role": "user",
            "content": "File a GSTR-1 return for GSTIN 29AAACQ3770E000"
        }
    ]
)

📦 Installation Methods

Method 1: Direct Installation (Recommended)

git clone https://github.com/yourusername/sandbox-gstr1-mcp.git
cd sandbox-gstr1-mcp
pip install -r requirements.txt

Method 2: Using Virtual Environment

git clone https://github.com/yourusername/sandbox-gstr1-mcp.git
cd sandbox-gstr1-mcp
python3.11 -m venv venv
source venv/bin/activate  # macOS/Linux
# or
venv\Scripts\activate  # Windows
pip install -r requirements.txt

Method 3: Docker

docker build -t sandbox-gstr1-mcp:1.0.0 .
docker run -e SANDBOX_API_KEY="your-key" sandbox-gstr1-mcp:1.0.0

🔐 Security

✅ Test credentials provided for safe development
✅ Environment variables for sensitive data
✅ No credentials in code or version control
✅ HTTPS for all API calls
✅ Comprehensive error handling and logging

🐛 Troubleshooting

MCP Server Not Appearing in Claude Desktop

Verify configuration file path is correct
Check Python path is accessible
Ensure all dependencies are installed
Restart Claude Desktop completely
Check Claude logs for errors

API Connection Errors

Verify API key is correct
Check internet connectivity
Confirm API URL is correct
Review server logs for details

Session Expired

Generate a new taxpayer session (valid for 6 hours).

For more troubleshooting, see CLAUDE_INTEGRATION.md.

📚 Examples

File a Nil Return

from server import generate_taxpayer_session, save_gstr1_data

session = generate_taxpayer_session(
    gstin="29AAACQ3770E000",
    username="taxpayer_username"
)

save_gstr1_data(
    access_token=session["access_token"],
    gstin="29AAACQ3770E000",
    ret_period="032026",
    gstr1_data={
        "fp": "032026",
        "gstin": "29AAACQ3770E000",
        "gt": 0,
        "cur_gt": 0,
        "b2b": [],
        "b2cl": [],
        "b2cs": [],
        "hsn": {"data": []},
        "docs": {"doc_det": []}
    }
)

File B2B Invoices

See EXAMPLES.md for complete examples including:

B2B invoices
B2CL large value invoices
B2CS small value transactions
HSN summaries
Credit notes
Error handling
Complete end-to-end workflow

🤝 Contributing

Contributions are welcome! Please:

Fork the repository
Create a feature branch
Make your changes
Write tests
Submit a pull request

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🔗 Resources

Sandbox.co - GST API Platform
Sandbox Developer Hub - API Documentation
Claude Desktop - AI Assistant
MCP Protocol - Protocol Documentation
GST Portal - Official GST Portal

📞 Support

For issues or questions:

Check the troubleshooting guide
Review the documentation
Check examples
Open an issue on GitHub

🎯 Roadmap

[ ] Support for GSTR-3B filing
[ ] Support for GSTR-9 filing
[ ] Batch filing for multiple returns
[ ] Webhook support for filing notifications
[ ] Dashboard for filing history
[ ] Multi-language support
[ ] Advanced error recovery

📊 Status

| Component | Status | |-----------|--------| | Core Server | ✅ Production Ready | | API Integration | ✅ Complete | | Claude Desktop | ✅ Tested | | Claude API | ✅ Supported | | Documentation | ✅ Comprehensive | | Tests | ✅ Passing |

🙏 Acknowledgments

Built on top of Sandbox.co APIs
Integrates with Claude via MCP Protocol
Inspired by the unified GSTR-1 skill

📝 Changelog

v1.0.0 (April 1, 2026)

Initial release
Complete GSTR-1 filing workflow
All 7 core tools implemented
Excel to JSON conversion
Comprehensive documentation
Full test suite
Claude Desktop integration
Claude API support

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Made with ❤️ for GST compliance automation

Version: 1.0.0 Last Updated: April 1, 2026 Python: 3.11+ License: MIT

Sandbox GSTR-1 MCP Server