Installing @prefecthq/fastmcp-ts gives you the fastmcp CLI as a fully self-contained binary — all dependencies are bundled, so it works wherever the package is installed:
Every command supports the global flags --quiet (suppress human-readable output) and --json (machine-readable output).
Run a server
fastmcp run starts a server file directly — TypeScript files run via tsx with no build step:
fastmcp run server.ts
fastmcp run server.ts --transport http --port 3000
fastmcp run server.ts --reload # restart on file change
Inspect a server
List a server’s tools, resources, and prompts — from a file (run in-process) or a running URL:
fastmcp inspect --file server.ts
fastmcp inspect --url http://localhost:3000
fastmcp inspect --file server.ts --json
fastmcp call invokes a tool (by name) or reads a resource (by URI). Arguments are passed as key=value pairs; non-string values are JSON-parsed:
fastmcp call add --file server.ts a=1 b=2
fastmcp call config://settings --url http://localhost:3000
For complex nested inputs, prefer --input-json over key=value pairs.
List components on a running server
fastmcp list --url http://localhost:3000
fastmcp list --url http://localhost:3000 --resources --prompts --json
Dev inspector
Open the MCP Inspector UI against a server file, with file-watch reload:
fastmcp dev inspector server.ts
Install into editors and clients
fastmcp install writes the server into a client’s MCP config. Six targets are supported:
fastmcp install claude-code server.ts
fastmcp install claude-desktop server.ts
fastmcp install cursor server.ts
fastmcp install gemini server.ts
fastmcp install goose server.ts
fastmcp install mcp-json server.ts # project-local mcp.json
--args (comma-separated) and --env (comma-separated KEY=VALUE pairs) to configure the server entry. Existing entries trigger an interactive overwrite confirmation.
Scan all known client config locations for MCP servers already configured on this machine:
Authentication
Commands that connect to remote servers accept --auth <token>, sent as a Bearer token:
fastmcp list --url https://mcp.example.com --auth $TOKEN
Pipelines and exit codes
The CLI keeps stdout clean for machine-readable data — tables, spinners, and status messages go to stderr. That makes it composable:
fastmcp call add --file server.ts a=1 b=2 | jq
fastmcp inspect --file server.ts --json | jq '.tools[].name'
0 success, 1 user error, 2 connection error, 3 server error. 
