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Use MCP servers on-demand via the mcp CLI tool - discover tools, resources, and prompts without polluting context with pre-loaded MCP integrations
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Use MCP servers on-demand via the mcp CLI tool - discover tools, resources, and prompts without polluting context with pre-loaded MCP integrations 📦 Ships with superpowers-lab
</> SKILL.md
mcp-cli.SKILL.md
---
name : mcp-cli
description : Use MCP servers on-demand via the mcp CLI tool - discover tools, resources, and prompts without polluting context with pre-loaded MCP integrations
---
# MCP CLI: On-Demand MCP Server Usage
Use the `mcp` CLI tool to dynamically discover and invoke MCP server capabilities without pre-configuring them as permanent integrations.
## When to Use This Skill
Use this skill when you need to:
- Explore an MCP server's capabilities before deciding to use it
- Make one-off calls to an MCP server without permanent integration
- Access MCP functionality without polluting the context window
- Test or debug MCP servers
- Use MCP servers that aren't pre-configured
## Prerequisites
The `mcp` CLI must be installed at `~/.local/bin/mcp`. If not present:
```bash
# Clone and build
cd /tmp && git clone --depth 1 https://github.com/f/mcptools.git
cd mcptools && CGO_ENABLED=0 go build -o ~/.local/bin/mcp ./cmd/mcptools
```
Always ensure PATH includes the binary:
```bash
export PATH="$HOME/.local/bin:$PATH"
```
## Discovery Workflow
### Step 1: Discover Available Tools
Flowy AI Flows that just work. Hand-picked Claude Code plugins that fire the right skill as you prompt.
```bash
mcp tools <server-command>
```
**Examples:**
```bash
# Filesystem server
mcp tools npx -y @modelcontextprotocol/server-filesystem /path/to/allow
# Memory/knowledge graph server
mcp tools npx -y @modelcontextprotocol/server-memory
# GitHub server (requires token)
mcp tools docker run -i --rm -e GITHUB_PERSONAL_ACCESS_TOKEN ghcr.io/github/github-mcp-server
# HTTP-based server
mcp tools https://example.com/mcp
```
### Step 2: Discover Resources (if supported)
```bash
mcp resources <server-command>
```
Resources are data sources the server exposes (files, database entries, etc.).
### Step 3: Discover Prompts (if supported)
```bash
mcp prompts <server-command>
```
Prompts are pre-defined prompt templates the server provides.
### Step 4: Get Detailed Info (JSON format)
```bash
# For full schema details including parameter types
mcp tools --format json <server-command>
mcp tools --format pretty <server-command>
```
## Making Tool Calls
### Basic Syntax
```bash
mcp call <tool_name> --params '<json>' <server-command>
```
### Examples
**Read a file:**
```bash
mcp call read_file --params '{"path": "/tmp/example.txt"}' \
npx -y @modelcontextprotocol/server-filesystem /tmp
```
**Write a file:**
```bash
mcp call write_file --params '{"path": "/tmp/test.txt", "content": "Hello world"}' \
npx -y @modelcontextprotocol/server-filesystem /tmp
```
**List directory:**
```bash
mcp call list_directory --params '{"path": "/tmp"}' \
npx -y @modelcontextprotocol/server-filesystem /tmp
```
**Create entities (memory server):**
```bash
mcp call create_entities --params '{"entities": [{"name": "Project", "entityType": "Software", "observations": ["Uses TypeScript"]}]}' \
npx -y @modelcontextprotocol/server-memory
```
**Search (memory server):**
```bash
mcp call search_nodes --params '{"query": "TypeScript"}' \
npx -y @modelcontextprotocol/server-memory
```
### Complex Parameters
For nested objects and arrays, ensure valid JSON:
```bash
mcp call edit_file --params '{
"path": "/tmp/file.txt",
"edits": [
{"oldText": "foo", "newText": "bar"},
{"oldText": "baz", "newText": "qux"}
]
}' npx -y @modelcontextprotocol/server-filesystem /tmp
```
### Output Formats
```bash
# Table (default, human-readable)
mcp call <tool> --params '{}' <server>
# JSON (for parsing)
mcp call <tool> --params '{}' -f json <server>
# Pretty JSON (readable JSON)
mcp call <tool> --params '{}' -f pretty <server>
```
## Reading Resources
```bash
# List available resources
mcp resources <server-command>
# Read a specific resource
mcp read-resource <resource-uri> <server-command>
# Alternative syntax
mcp call resource:<resource-uri> <server-command>
```
## Using Prompts
```bash
# List available prompts
mcp prompts <server-command>
# Get a prompt (may require arguments)
mcp get-prompt <prompt-name> <server-command>
# With parameters
mcp get-prompt <prompt-name> --params '{"arg": "value"}' <server-command>
```
## Server Aliases (for repeated use)
If using a server frequently during a session:
```bash
# Create alias
mcp alias add fs npx -y @modelcontextprotocol/server-filesystem /home/user
# Use alias
mcp tools fs
mcp call read_file --params '{"path": "README.md"}' fs
# List aliases
mcp alias list
# Remove when done
mcp alias remove fs
```
Aliases are stored in `~/.mcpt/aliases.json`.
## Authentication
### HTTP Basic Auth
```bash
mcp tools --auth-user "username:password" https://api.example.com/mcp
```
### Bearer Token
```bash
mcp tools --auth-header "Bearer your-token-here" https://api.example.com/mcp
```
### Environment Variables (for Docker-based servers)
```bash
mcp tools docker run -i --rm \
-e GITHUB_PERSONAL_ACCESS_TOKEN="$GITHUB_TOKEN" \
ghcr.io/github/github-mcp-server
```
## Transport Types
### Stdio (default for npx/node commands)
```bash
mcp tools npx -y @modelcontextprotocol/server-filesystem /tmp
```
### HTTP (auto-detected for http/https URLs)
```bash
mcp tools https://example.com/mcp
```
### SSE (Server-Sent Events)
```bash
mcp tools http://localhost:3001/sse
# Or explicitly:
mcp tools --transport sse http://localhost:3001
```
## Common MCP Servers
### Filesystem
```bash
# Allow access to specific directory
mcp tools npx -y @modelcontextprotocol/server-filesystem /path/to/allow
```
### Memory (Knowledge Graph)
```bash
mcp tools npx -y @modelcontextprotocol/server-memory
```
### GitHub
```bash
export GITHUB_PERSONAL_ACCESS_TOKEN="your-token"
mcp tools docker run -i --rm -e GITHUB_PERSONAL_ACCESS_TOKEN ghcr.io/github/github-mcp-server
```
### Brave Search
```bash
export BRAVE_API_KEY="your-key"
mcp tools npx -y @anthropic/mcp-server-brave-search
```
### Puppeteer (Browser Automation)
```bash
mcp tools npx -y @anthropic/mcp-server-puppeteer
```
## Best Practices
### 1. Always Discover First
Before calling tools, run `mcp tools` to understand what's available and the exact parameter schema.
### 2. Use JSON Format for Parsing
When you need to process results programmatically:
```bash
mcp call <tool> --params '{}' -f json <server> | jq '.field'
```
### 3. Validate Parameters
The table output shows parameter signatures. Match them exactly:
- `param:str` = string
- `param:num` = number
- `param:bool` = boolean
- `param:str[]` = array of strings
- `[param:str]` = optional parameter
### 4. Handle Errors Gracefully
Tool calls may fail. Check exit codes and stderr:
```bash
if ! result=$(mcp call tool --params '{}' server 2>&1); then
echo "Error: $result"
fi
```
### 5. Use Aliases for Multi-Step Operations
If making several calls to the same server:
```bash
mcp alias add tmp-server npx -y @modelcontextprotocol/server-filesystem /tmp
mcp call list_directory --params '{"path": "/tmp"}' tmp-server
mcp call read_file --params '{"path": "/tmp/file.txt"}' tmp-server
mcp alias remove tmp-server
```
### 6. Restrict Capabilities with Guard
For safety, limit what tools are accessible:
```bash
# Only allow read operations
mcp guard --allow 'tools:read_*,list_*' --deny 'tools:write_*,delete_*' \
npx -y @modelcontextprotocol/server-filesystem /home
```
## Debugging
### View Server Logs
```bash
mcp tools --server-logs <server-command>
```
### Check Alias Configuration
```bash
cat ~/.mcpt/aliases.json
```
### Verbose Output
Use `--format pretty` for detailed JSON output to debug parameter issues.
## Quick Reference
| Action | Command |
|--------|---------|
| List tools | `mcp tools <server>` |
| List resources | `mcp resources <server>` |
| List prompts | `mcp prompts <server>` |
| Call tool | `mcp call <tool> --params '<json>' <server>` |
| Read resource | `mcp read-resource <uri> <server>` |
| Get prompt | `mcp get-prompt <name> <server>` |
| Add alias | `mcp alias add <name> <server-command>` |
| Remove alias | `mcp alias remove <name>` |
| JSON output | Add `-f json` or `-f pretty` |
## Example: Complete Workflow
```bash
# 1. Discover what's available
mcp tools npx -y @modelcontextprotocol/server-filesystem /home/user/project
# 2. Check for resources
mcp resources npx -y @modelcontextprotocol/server-filesystem /home/user/project
# 3. Create alias for convenience
mcp alias add proj npx -y @modelcontextprotocol/server-filesystem /home/user/project
# 4. Explore directory structure
mcp call directory_tree --params '{"path": "/home/user/project"}' proj
# 5. Read specific files
mcp call read_file --params '{"path": "/home/user/project/README.md"}' proj
# 6. Search for patterns
mcp call search_files --params '{"path": "/home/user/project", "pattern": "**/*.ts"}' proj
# 7. Clean up alias
mcp alias remove proj
```
## Troubleshooting
### "command not found: mcp"
Ensure PATH is set: `export PATH="$HOME/.local/bin:$PATH"`
### JSON parse errors
- Escape special characters properly
- Avoid shell expansion issues by using single quotes around JSON
- For complex JSON, write to a temp file and use `--params "$(cat params.json)"`
### Server timeout
Some servers take time to start. The mcp CLI waits for initialization automatically.
### Permission denied
For filesystem server, ensure the allowed directory path is correct and accessible.
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