Claude-skill-registry fastmcp-client-cli

Query and invoke tools on MCP servers using fastmcp list and fastmcp call. Use when you need to discover what tools a server offers, call tools, or integrate MCP servers into workflows.

install

source · Clone the upstream repo

git clone https://github.com/majiayu000/claude-skill-registry

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/majiayu000/claude-skill-registry "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/data/fastmcp-client-cli" ~/.claude/skills/majiayu000-claude-skill-registry-fastmcp-client-cli && rm -rf "$T"

manifest: skills/data/fastmcp-client-cli/SKILL.md

source content

FastMCP CLI: List and Call

Use

fastmcp list

and

fastmcp call

to interact with any MCP server from the command line.

Listing Tools

# Remote server
fastmcp list http://localhost:8000/mcp

# Local Python file (runs via fastmcp run automatically)
fastmcp list server.py

# MCPConfig with multiple servers
fastmcp list mcp.json

# Stdio command (npx, uvx, etc.)
fastmcp list --command 'npx -y @modelcontextprotocol/server-github'

# Include full input/output schemas
fastmcp list server.py --input-schema --output-schema

# Machine-readable JSON
fastmcp list server.py --json

# Include resources and prompts
fastmcp list server.py --resources --prompts

Default output shows tool signatures and descriptions. Use

--input-schema

--output-schema

to include full JSON schemas,

--json

for structured output.

Calling Tools

# Key=value arguments (auto-coerced to correct types)
fastmcp call server.py greet name=World
fastmcp call server.py add a=3 b=4

# Single JSON object for complex/nested args
fastmcp call server.py create_item '{"name": "Widget", "tags": ["a", "b"]}'

# --input-json with key=value overrides
fastmcp call server.py search --input-json '{"query": "hello", "limit": 5}' limit=10

# JSON output for scripting
fastmcp call server.py add a=3 b=4 --json

Type coercion is automatic:

limit=5

becomes an integer,

verbose=true

becomes a boolean, based on the tool's input schema.

Server Targets

All commands accept the same server targets:

Target	Example
HTTP/HTTPS URL	`http://localhost:8000/mcp`
Python file	`server.py`
MCPConfig JSON	`mcp.json` (must have `mcpServers` key)
Stdio command	`--command 'npx -y @mcp/server'`
Discovered name	`weather` or `source:name`

Servers configured in editor configs (Claude Desktop, Claude Code, Cursor, Gemini CLI, Goose) or project-level

mcp.json

can be referenced by name. Use

source:name

(e.g.

claude-code:my-server

cursor:weather

) to target a specific source. Run

fastmcp discover

to see available names.

For SSE servers, pass

--transport sse

fastmcp list http://localhost:8000/mcp --transport sse

Auth

HTTP targets automatically use OAuth (no-ops if the server doesn't require auth). Disable with

--auth none

fastmcp call http://server/mcp tool --auth none

Discovering Configured Servers

# See all MCP servers in editor/project configs
fastmcp discover

# Filter by source
fastmcp discover --source claude-code

# JSON output
fastmcp discover --json

Scans Claude Desktop, Claude Code, Cursor, Gemini CLI, Goose, and

./mcp.json

. Sources:

claude-desktop

claude-code

cursor

gemini

goose

project

Workflow Pattern

Discover tools first, then call them:

# 1. See what servers are configured
fastmcp discover

# 2. See what tools a server has
fastmcp list weather

# 3. Call a tool
fastmcp call weather get_forecast city=London

If you call a nonexistent tool, FastMCP suggests close matches.