Agent-Skills.md

Agent Skills: MCP CLI: On-Demand MCP Server Access

On-demand MCP server access via CLI without adding to settings.json. Use when exploring MCP server capabilities before installing, making one-off calls, testing MCP servers during development, or avoiding context pollution from rarely-used servers.

UncategorizedID: HTRamsey/claude-config/mcp-cli

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HTRamsey/claude-config
HTRamsey
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skills/mcp-cli/SKILL.md

Skill Metadata

Name
mcp-cli
Description
On-demand MCP server access via CLI without adding to settings.json. Use when exploring MCP server capabilities before installing, making one-off calls, testing MCP servers during development, or avoiding context pollution from rarely-used servers.

MCP CLI: On-Demand MCP Server Access

Persona: MCP integration specialist - enables exploration and use of MCP servers without permanent configuration.

When NOT to Use

  • Frequently-used servers (add to settings.json instead)
  • Servers requiring complex persistent state
  • When MCP tool is already configured in Claude Code

Discovery Commands

# List available tools
mcp tools npx -y @modelcontextprotocol/server-filesystem /tmp

# List resources
mcp resources npx -y @modelcontextprotocol/server-filesystem /tmp

# List prompts
mcp prompts npx -y @modelcontextprotocol/server-memory

# JSON output for parsing
mcp tools --format json npx -y @modelcontextprotocol/server-filesystem /tmp

# Show server logs during discovery
mcp tools --server-logs npx -y @modelcontextprotocol/server-filesystem /tmp

Tool Invocation

# Basic syntax
mcp call <tool_name> --params '<json>' <server-command>

# Examples
mcp call read_file --params '{"path": "/tmp/test.txt"}' \
  npx -y @modelcontextprotocol/server-filesystem /tmp

mcp call write_file --params '{"path": "/tmp/out.txt", "content": "hello"}' \
  npx -y @modelcontextprotocol/server-filesystem /tmp

mcp call list_directory --params '{"path": "/tmp"}' \
  npx -y @modelcontextprotocol/server-filesystem /tmp

Common Servers

| Server | Command | Use For | |--------|---------|---------| | Filesystem | npx -y @modelcontextprotocol/server-filesystem /path | File operations | | Memory | npx -y @modelcontextprotocol/server-memory | Knowledge graphs | | GitHub | npx -y @modelcontextprotocol/server-github | Repo operations | | Brave Search | npx -y @anthropic/mcp-server-brave-search | Web search | | Playwright | npx -y @anthropic/mcp-server-playwright | Browser automation (Firefox, Chrome, WebKit) | | Puppeteer | npx -y @anthropic/mcp-server-puppeteer | Browser automation (Chrome only) |

Aliases (Session Shortcuts)

# Create alias for repeated use
mcp alias add fs npx -y @modelcontextprotocol/server-filesystem /home/user

# Use alias
mcp tools @fs
mcp call read_file --params '{"path": "file.txt"}' @fs

# Remove alias
mcp alias remove fs

Authentication

# HTTP Basic Auth
mcp call tool --auth-user user:pass --params '{}' https://api.example.com

# Bearer token
mcp call tool --auth-header "Authorization: Bearer TOKEN" --params '{}' https://api.example.com

# Environment variables (for Docker)
mcp call tool --params '{}' docker run -e API_KEY=xxx server-image

Transport Types

| Type | Auto-detected | Example | |------|---------------|---------| | stdio | npx, docker run | npx -y @mcp/server | | HTTP | URLs | https://api.example.com/mcp | | SSE | Explicit | --transport sse https://... |

Workflow

# 1. Discover what's available
mcp tools npx -y @modelcontextprotocol/server-filesystem /tmp

# 2. Check tool schema
mcp tools --format json npx -y @modelcontextprotocol/server-filesystem /tmp | jq '.[] | select(.name == "read_file")'

# 3. Call the tool
mcp call read_file --params '{"path": "/tmp/test.txt"}' \
  npx -y @modelcontextprotocol/server-filesystem /tmp

Should NOT Attempt

  • Using mcp-cli for servers already in settings.json (redundant)
  • Skipping discovery (always check tools first)
  • Malformed JSON in --params (validate before calling)
  • Calling without understanding parameter schema

Failure Behavior

If mcp commands fail:

  1. Check if mcp CLI is installed: which mcp && mcp --version
  2. Verify server command works standalone: npx -y @modelcontextprotocol/server-filesystem --help
  3. Check JSON params syntax: echo '{"key": "value"}' | jq .
  4. Use --format json to see detailed error responses
  5. Use --server-logs to see server-side errors

Escalation

| Situation | Action | |-----------|--------| | mcp CLI not installed | brew tap f/mcptools && brew install mcp | | Server frequently needed | Add to settings.json instead | | Complex multi-call workflow | Consider writing a script | | Auth issues | Check server docs for auth method |

Related Skills

  • browser-automation: Uses Puppeteer/Playwright MCP servers
  • hook-creator: MCP tools can be used in hooks