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test-server

Use test-server for quick MCP smoke checks against a running server.

Command

openapi-to-mcp test-server [OPTIONS]

Options

Option Required Default Meaning
--transport Yes None streamable-http or stdio
--host No localhost Hostname for streamable-http
--port No 8080 Port for streamable-http
--mcp-endpoint No /mcp HTTP MCP endpoint path
--list-tools No Off Send a tools/list request
--server-cmd No None Server startup command for stdio
--tool-name No None Tool name for tools/call
--tool-args No None JSON object string for tool arguments
--env-source No None stdio env values as JSON or file path

Modes

List tools

openapi-to-mcp test-server \
  --transport streamable-http \
  --host 127.0.0.1 \
  --port 8080 \
  --mcp-endpoint /mcp \
  --list-tools

Call a tool over streamable HTTP

openapi-to-mcp test-server \
  --transport streamable-http \
  --host 127.0.0.1 \
  --port 8080 \
  --mcp-endpoint /mcp \
  --tool-name getPetById \
  --tool-args '{"petId":1}'

List tools over stdio

openapi-to-mcp test-server \
  --transport stdio \
  --server-cmd "node ./generated-server/build/index.js" \
  --env-source ./generated-server/.env \
  --list-tools

Call a tool over stdio with inline env JSON

openapi-to-mcp test-server \
  --transport stdio \
  --server-cmd "node ./generated-server/build/index.js" \
  --env-source '{"TARGET_API_BASE_URL":"https://example.com/api"}' \
  --tool-name getPetById \
  --tool-args '{"petId":1}'

Validation rules

  • --server-cmd is required for stdio
  • --mcp-endpoint must start with /
  • --tool-args requires --tool-name
  • you must choose --list-tools or --tool-name

Output behavior

test-server prints a formatted JSON panel with the raw response payload returned by the transport adapter.

For quick local smoke tests, this is intentionally low-friction rather than highly normalized.

For Streamable HTTP, the command follows only same-origin 307 or 308 redirects, plus an upgrade from HTTP port 80 to HTTPS port 443 on the same host. Other redirects fail before the request or session identifier is forwarded.

--env-source formats

Accepted values:

  • a JSON string
  • a path to a .json file
  • a path to a .env file

When to use MCP Inspector instead

Use test-server for automation or quick terminal checks.

Use the MCP Inspector guide when you want a GUI for exploring tools and sending requests interactively.