MCP Tool Chainer Server: Streamlining MCP Tool Integration

The MCP Tool Chainer Server is a powerful solution for chaining multiple MCP (Model Context Protocol) tools together, enabling sequential execution with result passing. Designed to address modelcontextprotocol/specification#215, this server minimizes token usage and simplifies complex workflows.

Key Features

• Tool Chaining: Execute multiple MCP tools in sequence.
• Result Passing: Use the CHAIN_RESULT placeholder to pass results between tools.
• JsonPath Filtering: Extract specific data using inputPath and outputPath parameters.
• Automatic Tool Discovery: Discover tools from configured MCP servers.
• Token Efficiency: Reduce token usage compared to individual tool calls.

Tools Implemented

1. mcp_chain: Chains multiple MCP servers together.
2. chainable_tools: Discovers tools from all MCP servers for use with mcp_chain.
3. discover_tools: Rediscover tools from all MCP servers.

Installation

Prerequisites

• Node.js (v16 or later)
• npm

Installing from npm

# Install
npm install @thirdstrandstudio/mcp-tool-chainer

# Or use with npx directly
npx -y @thirdstrandstudio/mcp-tool-chainer

Installing from Source

# Clone the repository
git clone https://github.com/thirdstrandstudio/mcp-tool-chainer.git
cd mcp-tool-chainer

# Install dependencies
npm install

# Build the package
npm run build

Usage with Claude Desktop and Cursor

Ensure the MCP Tool Chainer is the last MCP server to run. Add the following to your claude_desktop_config.json or mcp.json:

If Installed from npm Globally

{
  "mcpServers": {
    "mcp_tool_chainer": {
      "command": "npx",
      "args": ["-y", "@thirdstrandstudio/mcp-tool-chainer", "`claude_desktop_config.json` or `mcp.json`"],
      "env": {}
    }
  }
}

If Installed from Source

{
  "mcpServers": {
    "mcp_tool_chainer": {
      "command": "node",
      "args": ["/path/to/mcp-tool-chainer/dist/index.js", "`claude_desktop_config.json` or `mcp.json`"],
      "env": {}
    }
  }
}

Replace /path/to/mcp-tool-chainer with the actual path to your repository.

Examples

Chain Browser and XPath Tools

// Fetch a webpage and then extract specific content with XPath
const result = await callTool("mcp_chain", { 
  "mcpPath": [
    {
      "toolName": "mcp_browser_mcp_fetch_url",
      "toolArgs": "{\"url\": \"https://example.com\"}"
    },
    {
      "toolName": "mcp_xpath_xpath",
      "toolArgs": "{\"xml\": CHAIN_RESULT, \"query\": \"//h1\"}"
    }
  ]
});

Using JsonPath with InputPath and OutputPath

// Fetch a webpage, extract specific content with XPath, then extract part of the result
const result = await callTool("mcp_chain", { 
  "mcpPath": [
    {
      "toolName": "mcp_fetch_fetch",
      "toolArgs": "{\"url\": \"https://api.example.com/data\"}"
    },
    {
      "toolName": "web_search",
      "toolArgs": "{\"search_term\": CHAIN_RESULT}",
      "inputPath": "$.results[0].title",     // Extract only the first result's title from previous output
      "outputPath": "$.snippets[*].text"     // Extract only the text snippets from the search results
    },
    {
      "toolName": "another_tool",
      "toolArgs": "{\"content\": CHAIN_RESULT}"
    }
  ]
});

JsonPath Support

The MCP Tool Chainer supports AWS Step Functions-style inputPath and outputPath features:

• inputPath: JsonPath expression to extract specific portions of the input before passing to a tool.
• outputPath: JsonPath expression to extract specific portions of the output before passing to the next tool.

For JsonPath syntax reference, see JsonPath Syntax.

Benefits

• Reduced Token Usage: Minimize token consumption by avoiding large intermediate results.
• Simplified Workflows: Create complex pipelines with a single tool call.
• Improved Performance: Reduce latency by minimizing round-trips between the LLM and tools.
• Precise Data Flow Control: Extract only the data you need with JsonPath expressions.

Development

# Install dependencies
npm install

# Start the server
node dist/index.js config.json

# List available tools
node dist/index.js config.json discover_tools

License

This MCP server is licensed under the MIT License.

Created by Third Strand Studio.