CLI Reference¶

MCP Generator installs three CLI commands.

generate-mcp¶

Generate a FastMCP 3.x server from an OpenAPI spec.

generate-mcp [OPTIONS]

Options¶

Option	Default	Description
`--file <path>`	`./openapi.json`	Path to OpenAPI spec file (JSON or YAML)
`--url <url>`	—	Download spec from URL (overrides `--file`)
`--enable-storage`	off	Enable persistent storage backend
`--enable-caching`	off	Enable response caching (requires `--enable-storage`)
`--enable-resources`	off	Expose GET endpoints as MCP resources
`--fastmcp-target <3\\|4>`	`4`	FastMCP major version the generated server targets

FastMCP target version¶

Generated servers target FastMCP 4 by default, which is built on the MCP Python SDK v2 and serves the sessionless 2026-07-28 protocol alongside handshake-era clients. Pass --fastmcp-target 3 to emit for the FastMCP 3 line instead, which upstream maintains for MCP SDK v1 users.

Three things differ in the emitted server:

Concern	Target 4 (default)	Target 3
Missing required parameters	Tool returns what it needs — elicitation cannot reach a client that negotiates the modern protocol	`ctx.elicit()` asks the client
API error recovery	Error is raised on its own — server-side sampling is removed in 4.x	`ctx.sample()` asks the caller's model for a hint
HTTP client	`httpx2` — FastMCP 4 replaced httpx across its whole stack	`httpx`

Target 4 also floors pydantic at >=2.12, which is the MCP SDK v2 requirement: below it, installation fails resolution outright rather than upgrading.

Examples¶

# Local file (default)
generate-mcp

# Custom file
generate-mcp --file ./my-api.yaml

# From URL
generate-mcp --url https://petstore3.swagger.io/api/v3/openapi.json

# Target the FastMCP 3 line instead of the default 4
generate-mcp --file ./openapi.json --fastmcp-target 3

# All features enabled
generate-mcp --url https://example.com/api.json \
  --enable-storage --enable-caching --enable-resources

register-mcp¶

Manage the local server registry at ~/.mcp-generator/servers.json.

register-mcp <COMMAND> [OPTIONS]

Commands¶

Command	Description
`add <path>`	Register a generated server (default when a path is given)
`list`	Show all registered servers
`remove <name>`	Unregister a server by name
`export <name>`	Export server metadata as `server.json`

Options¶

Option	Command	Description
`--json`	`list`	Output as JSON for scripting
`-o, --output <file>`	`export`	Write to file (default: stdout)

Examples¶

# Register (explicit)
register-mcp add ./generated_mcp

# Register (shorthand)
register-mcp ./generated_mcp

# List registered servers
register-mcp list

# List as JSON
register-mcp list --json

# Remove
register-mcp remove swagger_petstore_openapi

# Export metadata
register-mcp export swagger_petstore_openapi -o server.json

run-mcp¶

Run a registered server by name.

run-mcp <SERVER_NAME> [OPTIONS]

Options¶

Option	Default	Description
`--list`	—	List registered servers and exit
`--mode` / `--transport`	`stdio`	Transport mode: `stdio` or `http`
`--host`	`0.0.0.0`	HTTP host
`--port`	`8000`	HTTP port
`--validate-tokens`	off	Enable JWT validation (HTTP mode)

Examples¶

# List servers
run-mcp --list

# Run via STDIO
export API_TOKEN="your-token"
run-mcp swagger_petstore_openapi

# Run via HTTP
run-mcp swagger_petstore_openapi --mode http --port 8000

# HTTP with JWT validation
run-mcp swagger_petstore_openapi --mode http --port 8000 --validate-tokens

Notes¶

The registry lives at ~/.mcp-generator/servers.json
run-mcp forwards flags to the generated server's entry point
You can also run the generated script directly: python <name>_mcp_generated.py