Universal MCP Client

Connect to any MCP server with progressive disclosure - load tool schemas on-demand instead of dumping thousands of tokens into context upfront.

Skill Location

This skill is located at: .claude/skills/mcp-client/

Script path: .claude/skills/mcp-client/scripts/mcp_client.py

Configuration

The script looks for config in this order:

• MCP_CONFIG_PATH env var (custom path)

• references/mcp-config.json (this skill's config - recommended)

• .mcp.json in project root

• ~/.claude.json

Your config file: .claude/skills/mcp-client/references/mcp-config.json

Edit this file to add your API keys. The example file (example-mcp-config.json ) is kept as a reference template.

If the user hasn't provided their Zapier API key yet, ask them for it.

Running Commands

All commands use the script at .claude/skills/mcp-client/scripts/mcp_client.py :

List configured servers

python .claude/skills/mcp-client/scripts/mcp_client.py servers

List tools from a server

python .claude/skills/mcp-client/scripts/mcp_client.py tools <server_name>

Call a tool

python .claude/skills/mcp-client/scripts/mcp_client.py call <server> <tool> '{"arg": "value"}'

Workflow

• Check config exists - Run servers command. If error, create .mcp.json

• List servers - See what MCP servers are configured

• List tools - Get tool schemas from a specific server

• Call tool - Execute a tool with arguments

Commands Reference

Command Description

servers

List all configured MCP servers

tools <server>

List tools with full parameter schemas

call <server> <tool> '<json>'

Execute a tool with arguments

Example: Zapier

1. List servers to confirm Zapier is configured

python .claude/skills/mcp-client/scripts/mcp_client.py servers

2. List Zapier tools

python .claude/skills/mcp-client/scripts/mcp_client.py tools zapier

3. Call a Zapier tool

python .claude/skills/mcp-client/scripts/mcp_client.py call zapier <tool_name> '{"param": "value"}'

Example: Sequential Thinking

1. List tools

python .claude/skills/mcp-client/scripts/mcp_client.py tools sequential-thinking

2. Use sequential thinking

python .claude/skills/mcp-client/scripts/mcp_client.py call sequential-thinking sequentialthinking '{"thought": "Breaking down the problem...", "thoughtNumber": 1, "totalThoughts": 5, "nextThoughtNeeded": true}'

Config Format

Config file format (references/mcp-config.json ):

{ "mcpServers": { "zapier": { "url": "https://mcp.zapier.com/api/v1/connect", "api_key": "your-api-key" }, "sequential-thinking": { "command": "npx", "args": ["-y", "@modelcontextprotocol/server-sequential-thinking"] } } }

Transport detection:

• url

• api_key → FastMCP with Bearer auth (Zapier)

• command

• args → stdio (local servers like sequential-thinking)

• url ending in /sse → SSE transport

• url ending in /mcp → Streamable HTTP

Error Handling

Errors return JSON:

{"error": "message", "type": "configuration|validation|connection"}

• configuration

• Config file not found. Create .mcp.json

• validation

• Invalid server or tool name

• connection

• Failed to connect to server

Dependencies

pip install mcp fastmcp

References

• references/example-mcp-config.json

• Template config file

• references/mcp-servers.md

• Common server configurations

• references/python-mcp-sdk.md

• Python SDK documentation