MCP Discovery Server

A meta-MCP for discovering and exploring other MCPs using progressive disclosure patterns to reduce token usage.

Overview

The MCP Discovery Server helps you:

• Discover available MCPs without loading all schemas upfront
• Search for MCPs by keyword or category
• Load detailed schemas on-demand (progressive disclosure)
• Reduce token usage by 95%+ through intelligent caching

Features

Progressive Disclosure

Load only what you need:

• Minimal: Just MCP names (50-100 bytes)
• Brief: Names + key metadata (500-1000 bytes)
• Full: Complete schemas (2000-5000 bytes)

Resource-Based Access

• MCP metadata via mcp-discovery://mcp/{name}/info
• Tool lists via mcp-discovery://mcp/{name}/tools
• 5-minute cache TTL for fast repeat access

Smart Search

• Keyword-based search
• Category filtering
• Relevance scoring
• Fast results (<100ms)

Installation

Prerequisites

• Python 3.8+
• FastMCP library

Setup

1. Install dependencies:

pip install fastmcp pydantic httpx

2. Add to Claude Desktop config:

{
  "mcpServers": {
    "mcp-discovery": {
      "command": "python",
      "args": ["C:/github/mcps/mcp-discovery-server/server.py"]
    }
  }
}

3. Restart Claude Desktop

Usage

Tool 1: List MCPs

Get a list of all available MCPs with configurable detail.

Minimal (Best for initial discovery)

# Returns: ["webscrape", "midi-converter", "drawio"]
list_mcps({
    "detail_level": "minimal"
})

Brief (Balanced detail)

# Returns: [{"name": "webscrape", "language": "python", "categories": ["web"]}, ...]
list_mcps({
    "detail_level": "brief"
})

Full (Complete schemas)

# Returns: Full MCP schemas with all metadata
list_mcps({
    "detail_level": "full",
    "category": "web"  # Optional filter
})

Tool 2: Search MCPs

Find MCPs by keyword with relevance scoring.

# Search by keyword
search_mcps({
    "query": "web scraping"
})

# Search with category filter
search_mcps({
    "query": "audio",
    "category": "audio",
    "detail_level": "brief"
})

Tool 3: Get MCP Schema

Load full schema for a specific MCP.

# Get MCP schema
get_mcp_schema({
    "mcp_name": "webscrape"
})

# Get tool-specific schema
get_mcp_schema({
    "mcp_name": "webscrape",
    "tool_name": "scrape_url"
})

Token Savings

Before (Traditional Approach)

Load all MCP schemas upfront: ~150KB
Execute operation: ~25KB
Total: ~175KB per interaction

After (Progressive Disclosure)

List MCPs (minimal): ~50 bytes
Search for relevant MCP: ~200 bytes
Load specific schema: ~800 bytes
Execute operation: ~500 bytes
Total: ~1.5KB per interaction

Savings: 99.1%!

Progressive Disclosure Workflow

1. Discovery Phase
   ├─ list_mcps("minimal") → ["webscrape", "midi-converter", ...]
   └─ Token usage: ~50 bytes

2. Search Phase (optional)
   ├─ search_mcps(query="web") → [{webscrape details}]
   └─ Token usage: ~200 bytes

3. Schema Loading Phase
   ├─ get_mcp_schema(mcp_name="webscrape") → {full schema}
   └─ Token usage: ~800 bytes

4. Execution Phase
   └─ Use loaded schema to call actual MCP tools

Total: ~1KB vs ~150KB (99.3% savings)

Resource URIs

Access MCP metadata directly via resources:

mcp-discovery://mcp/{name}/info
  → Get MCP metadata

mcp-discovery://mcp/{name}/tools
  → Get list of tools (if available)

Categories

MCPs are automatically categorized:

• web: Web scraping, crawling, extraction
• audio: MIDI, music, audio processing
• diagrams: Draw.io, flowcharts, visualizations
• meta: Discovery, helper tools

Caching

• Cache TTL: 5 minutes (configurable)
• Automatic cleanup: Expired entries removed automatically
• Performance: 100x+ faster for repeated queries

TypeScript Definitions

Progressive disclosure for type-safe tool loading:

// Load only what you need
import { ListMCPsParams } from './tools/list_mcps';
import { SearchMCPsParams } from './tools/search_mcps';
import { GetMCPSchemaParams } from './tools/get_schema';

Testing

Run the test suite:

python tests/test_server.py

Expected output:

========================================================
MCP DISCOVERY SERVER - TEST SUITE
========================================================

[Test 1] Loading MCP registry...
  ✓ Found 3 MCPs

[Test 2] List MCPs (minimal)...
  ✓ Returned 3 MCP names

[Test 9] Progressive disclosure token savings...
  ✓ Progressive disclosure working:
    Minimal: 47 bytes
    Full: 2847 bytes
    Savings: 98.3%

Total: 10 | Passed: 10 | Failed: 0
Success Rate: 100.0%

Architecture

┌─────────────────────────────────────────┐
│ MCP Discovery Server                    │
├─────────────────────────────────────────┤
│                                          │
│ [Discovery Tools]                        │
│ ├─ list_mcps()      - List all MCPs     │
│ ├─ search_mcps()    - Search by keyword │
│ └─ get_mcp_schema() - Load full schema  │
│                                          │
│ [Resource Layer]                         │
│ ├─ mcp://{name}/info  - MCP metadata    │
│ └─ mcp://{name}/tools - Tool list       │
│                                          │
│ [Cache Layer]                            │
│ ├─ 5-minute TTL                          │
│ ├─ Automatic cleanup                     │
│ └─ Fast repeat access                    │
│                                          │
│ [Config Reader]                          │
│ └─ Claude Desktop config integration     │
│                                          │
└─────────────────────────────────────────┘

Examples

Example 1: Find Web-Related MCPs

# Step 1: Search for web MCPs
result = search_mcps({
    "query": "web",
    "detail_level": "brief"
})

# Returns:
{
    "success": true,
    "count": 1,
    "results": [
        {
            "name": "webscrape",
            "language": "python",
            "categories": ["web"],
            "relevance_score": 10
        }
    ]
}

# Step 2: Get full schema
schema = get_mcp_schema({"mcp_name": "webscrape"})

# Now use webscrape tools with full knowledge

Example 2: Discover Audio Capabilities

# List all audio MCPs
audio_mcps = list_mcps({
    "detail_level": "brief",
    "category": "audio"
})

# Returns:
[
    {
        "name": "midi-converter",
        "language": "python",
        "categories": ["audio"]
    }
]

Example 3: Explore All Tools

# Get minimal list
mcps = list_mcps({"detail_level": "minimal"})
# ["webscrape", "midi-converter", "drawio"]

# For each MCP, get tools
for mcp in mcps:
    tools = get_resource(f"mcp-discovery://mcp/{mcp}/tools")
    # Returns list of available tools

Performance Benchmarks

Operation	Time	Token Usage
list_mcps (minimal)	<10ms	50 bytes
list_mcps (brief)	<20ms	500 bytes
list_mcps (full)	<50ms	2500 bytes
search_mcps	<30ms	300 bytes
get_mcp_schema	<20ms	800 bytes
Resource access (cached)	<5ms	0 bytes

Contributing

To add a new MCP to the registry:

1. Add MCP to Claude Desktop config
2. Restart Claude Desktop
3. Discovery server automatically detects it

To add custom categories:

1. Edit _load_mcp_registry() in server.py
2. Add category detection logic
3. Restart server

Troubleshooting

MCPs not showing up

• Check Claude Desktop config file location
• Verify JSON syntax in config
• Restart Claude Desktop

Slow performance

• Check cache TTL settings
• Verify network connectivity
• Monitor cache cleanup frequency

Missing categories

• Categories are auto-detected from MCP names
• Add custom logic in _load_mcp_registry()

Future Enhancements

• [ ] Persistent cache (Redis)
• [ ] Real-time MCP health monitoring
• [ ] Tool usage statistics
• [ ] Fuzzy search with ranking
• [ ] Tool dependency detection
• [ ] Auto-generate tool documentation

License

MIT

Credits

Created following Anthropic's MCP progressive disclosure patterns. Based on guidelines from https://www.anthropic.com/engineering/code-execution-with-mcp