MCP Tools

Select a tool from the sidebar, fill in its arguments, and execute it. MCP Studio handles two kinds of tools: ones that return plain data and ones that return an interactive widget.

How to call a tool

1

Pick a tool

Click any tool name in the left sidebar under the active profile. The execution panel loads its argument schema.
2

Fill in the arguments

Enter values for each argument in the Tool Arguments tab. Arguments are validated against the tool's schema before the call is sent.
3

Execute

Click Execute. The response appears in the Logs panel. If the tool returns a widget, it renders automatically in the Widget Preview panel.

Executing a tool in MCP Studio — Executing a tool and inspecting the response in the log.

Non-interactive tool

Some tools return plain data — text, JSON, or markdown. The response is displayed in the Widget Preview panel as a read-only view. There is nothing to click or interact with; the panel just shows you what the server returned.

Example — read_me (Excalidraw)

Calling read_me returns a text description of the current Excalidraw canvas. MCP Studio renders it in the preview panel as static content — no interaction needed.

read_me tool result in MCP Studio — read_me returns plain data shown as a read-only view.

Interactive tool

Other tools return a widget — a live UI rendered inside an iframe in the Widget Preview panel. You can click, type, drag, and interact with it exactly as an end user would. Any interactions can be recorded and turned into an automated test step.

Example — create_view (Excalidraw)

Pass an elements array and Excalidraw renders a live, interactive diagram in the preview panel. The example below draws two boxes connected by an arrow: Hello → MCP Studio.

create_view — arguments

{
  "elements": "[
    { \"type\": \"cameraUpdate\", \"width\": 800, \"height\": 600, \"x\": 0, \"y\": 0 },
    { \"type\": \"rectangle\", \"id\": \"b1\", \"label\": { \"text\": \"Hello\" }, ... },
    { \"type\": \"arrow\",     \"id\": \"a1\", ... },
    { \"type\": \"rectangle\", \"id\": \"b2\", \"label\": { \"text\": \"MCP Studio\" }, ... }
  ]"
}

create_view result rendered in MCP Studio — create_view renders Hello → MCP Studio as an interactive diagram.

Interactive widget rendered after calling create_view — Interacting with the live widget after calling create_view.

At a glance

Non-interactive

e.g. read_me

Returns text, JSON, or markdown
Preview panel shows data as read-only
No clickable UI elements

Interactive

e.g. create_view

Returns a widget (live iframe)
Preview panel renders a full UI
Clicks and inputs can be recorded as test steps

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