tool-hub-mcp

Serverless MCP Aggregator - Reduce AI context token consumption

Problem

When using multiple MCP servers with AI clients (Claude Code, OpenCode, etc.), each server exposes all its tools to the AI context window. More servers = more tokens consumed before you even start working.

Solution

tool-hub-mcp acts as a single MCP gateway that exposes only 2 meta-tools:

The AI calls these meta-tools to discover and execute tools on-demand, instead of loading all tool definitions upfront.

Benchmark

Measured in Claude Code v2.1.6 using --output-format json to get exact input_tokens count.

Test: 6 MCP servers (jira, Playwright, mcp-outline, shadcn, chrome-devtools, Figma)

Larger Test: 7 MCP servers (98 tools total)

Token Optimization (v1.2.0):

• Compact JSON (no indentation): ~35% reduction
• Removed redundant fields: ~40% per search result
• Result: 43.7% savings on 2 results, ~70% on 10 results

Installation

# Zero-install (recommended) - works with npx, bunx, pnpm dlx, yarn dlx
npx @khanglvm/tool-hub-mcp setup

# Alternative: Go install
go install github.com/khanglvm/tool-hub-mcp/cmd/tool-hub-mcp@latest

Quick Start

# 1. Import your existing MCP configs
tool-hub-mcp setup

# 2. Add to your AI client
# Claude Code:
claude mcp add -s user tool-hub -- npx -y @khanglvm/tool-hub-mcp serve

Usage

Import Configs from AI Tools

# Auto-detect and import from Claude Code, OpenCode, etc.
tool-hub-mcp setup

Add MCP Servers Manually

# Paste any MCP config format (auto-detected)
tool-hub-mcp add --json '{
  "mcpServers": {
    "jira": {"command": "npx", "args": ["-y", "@lvmk/jira-mcp"]},
    "outline": {"command": "uvx", "args": ["mcp-outline"]}
  }
}'

# Or use flags
tool-hub-mcp add jira --command npx --arg -y --arg @lvmk/jira-mcp

Manage Servers

# List all servers
tool-hub-mcp list

# Remove a server
tool-hub-mcp remove jira

# Verify configuration
tool-hub-mcp verify

Run MCP Server

# Start server (stdio transport)
tool-hub-mcp serve

# Via AI client (already configured)
claude mcp add tool-hub -- tool-hub-mcp serve

Export Tool Index for Bash/Grep

Generate a local index file for offline tool search without MCP overhead:

# Export to default location (~/.tool-hub-mcp-index.jsonl)
tool-hub-mcp export-index

# Custom output path
tool-hub-mcp export-index --output ./my-tools.jsonl

# JSON array format (instead of JSONL)
tool-hub-mcp export-index --format json

Auto-regeneration: Index automatically updates when you run setup, add, or remove commands.

Bash/Grep Usage Examples:

# Find tools by server
grep '"jira"' ~/.tool-hub-mcp-index.jsonl

# Search tool descriptions
grep -i "search" ~/.tool-hub-mcp-index.jsonl | jq -r '.tool'

# List all tools
cat ~/.tool-hub-mcp-index.jsonl | jq -r '.tool'

# Count tools per server
cat ~/.tool-hub-mcp-index.jsonl | jq -r '.server' | sort | uniq -c

# Complex query: Find Jira tools with "issue" in description
grep '"jira"' ~/.tool-hub-mcp-index.jsonl | grep -i "issue" | jq .

Why use bash/grep?

• Zero MCP overhead (no process spawning)
• Works offline (local file)
• Standard Unix tools (no dependencies)
• Scriptable and composable

Benchmark Performance

# Compare token consumption
tool-hub-mcp benchmark

# Measure latency
tool-hub-mcp benchmark speed

Commands

Supported Config Sources

• Claude Code (~/.claude.json, .mcp.json)
• OpenCode (~/.opencode.json)
• Google Antigravity (~/.gemini/antigravity/mcp_config.json)
• Gemini CLI (~/.gemini/settings.json)
• Cursor (~/.cursor/mcp.json)
• Windsurf (~/.codeium/windsurf/mcp_config.json)

How It Works

┌─────────────────────────────────────────────────────────┐
│                     AI Client                           │
│              (Claude Code, OpenCode, etc.)              │
└───────────────────────┬─────────────────────────────────┘
                        │ 2 meta-tools
                        ▼
┌─────────────────────────────────────────────────────────┐
│                   tool-hub-mcp                          │
│           hub_search │ hub_execute                      │
└───────────────────────┬─────────────────────────────────┘
                        │ On-demand spawning
        ┌───────────────┼───────────────┐
        ▼               ▼               ▼
   ┌─────────┐    ┌─────────┐    ┌─────────┐
   │  Jira   │    │ Outline │    │  Figma  │
   │  MCP    │    │   MCP   │    │   MCP   │
   └─────────┘    └─────────┘    └─────────┘

AI Workflow:

1. Calls hub_search("what I need") to find tools with ranked results
2. Calls hub_execute(server, tool, args, searchId) to execute (learning tracks usage)

Result: Tool definitions loaded on-demand, intelligent ranking improves over time.

Architecture

Technology Stack:

• Language: Go 1.22+ (0.88ms startup)
• Distribution: Zero-install npm + Go binary
• Transport: JSON-RPC 2.0 over stdio
• Protocol: MCP 2024-11-05

Key Design Decisions:

• Lazy Spawning: Processes start only when tools accessed
• Process Pool: Reuse spawned processes (default: 3)
• Safe Request IDs: Atomic counter (not UnixNano) for JS compatibility
• Stderr Draining: Prevents pipe buffer deadlock

Performance

Token Efficiency:

• 38-97% reduction vs traditional approach
• v1.2.0: Additional 43-70% savings per search
• Scales better with more servers
• Bash/grep alternative: Zero tokens (offline)

Speed:

• Cold start: ~845ms (first tool call)
• Warm start: ~50ms (process reuse)
• Average: 307ms across 5 servers

Memory:

• Config: ~1KB per server
• Process: ~5-10MB per active server
• Pool: ~15-30MB (3 processes)

Configuration

Config Location: ~/.tool-hub-mcp.json

Format:

{
  "servers": {
    "serverName": {
      "command": "npx",
      "args": ["-y", "@package/name"],
      "env": {"KEY": "value"},
      "source": "claude-code"
    }
  },
  "settings": {
    "cacheToolMetadata": true,
    "processPoolSize": 3,
    "timeoutSeconds": 30
  }
}

Development Workflow

Setup

Install git hooks for automatic testing:

make setup-hooks

Testing

# Run all tests
make test

# Run tests with race detector
make test-race

# Run fast tests (pre-commit)
make test-fast

# Run full suite with coverage check (pre-push)
make test-coverage

Git Hooks

• Pre-commit: Runs fast tests on changed packages (~10s)
• Pre-push: Runs full suite with coverage check (~60s, requires 80% coverage)
• Bypass: Use git commit --no-verify or git push --no-verify for emergencies

The hooks prevent failing code from reaching the remote repository. Coverage threshold is enforced at 80%.

Documentation

Comprehensive documentation available in /docs/:

• Project Overview & PDR: /docs/project-overview-pdr.md
• Code Standards: /docs/code-standards.md
• Codebase Summary: /docs/codebase-summary.md
• System Architecture: /docs/system-architecture.md
• Design Guidelines: /docs/design-guidelines.md
• Deployment Guide: /docs/deployment-guide.md
• Project Roadmap: /docs/project-roadmap.md

Contributing

Contributions welcome! Please see:

• /docs/ for architecture and design guidelines
• /CLAUDE.md for development workflows
• GitHub Issues for bug reports and feature requests

License

MIT

Links

• npm: https://www.npmjs.com/package/@khanglvm/tool-hub-mcp
• GitHub: https://github.com/khanglvm/tool-hub-mcp
• MCP Protocol: https://modelcontextprotocol.io/