mcp

name	mcp
description	Call Tinker plugin MCP tools from the CLI or wire plugins into MCP clients. Covers listing tool schemas, one-shot tool invocation with tinker call, and stdio MCP servers with tinker mcp. When a plugin has no MCP tools, fall back to the debug skill (tinker open + agent-browser UI automation). Use when the user asks to call a plugin tool, automate a plugin programmatically, integrate a Tinker plugin with Cursor or Claude Code via MCP, use tinker tools, tinker call, or tinker mcp, or work with plugins marked [mcp] in tinker list.
allowed-tools	Bash(tinker:*)

Tinker MCP

Tinker plugins can expose Model Context Protocol tools in their package.json under tinker.mcp.tools. The CLI bridges agents to those tools in two ways: direct calls (tinker call) and stdio MCP servers (tinker mcp).

Plugins with MCP support are tagged [mcp] in tinker list. The plugin must be running before any tool call. Open it first with tinker open <plugin>.

Plugins without [mcp] have no tinker tools / tinker call API. To automate them anyway, load the debug skill and drive the plugin UI with agent-browser after tinker open (see When MCP is not available).

The MCP loop

tinker list                              # find plugins tagged [mcp]
tinker open <plugin>                     # start the plugin window
tinker tools <plugin>                    # inspect tool names and input schemas
tinker call <plugin> --tool <name> [--args '<json-object>']

For MCP clients (Cursor, Claude Code, etc.) that spawn a server process, use tinker mcp <plugin> instead of call for ongoing sessions.

Plugin names accept the short form (json-editor) or the full id (tinker-json-editor).

Quickstart

tinker list
tinker open json-editor
tinker tools json-editor

tinker call json-editor --tool get

tinker call json-editor --tool set --args '{"content":"{\"hello\":true}"}'

tinker call json-editor --tool format

Listing tools

tinker tools <plugin>

Prints the plugin's MCP tool definitions as JSON: names, descriptions, and inputSchema for each tool. Run this before the first call to learn required argument shapes.

Example tools on tinker-json-editor:

Tool	Purpose
get	Read current editor content, validation state, mode, line count
set	Replace editor content (content string argument)
format	Pretty-print valid JSON
minify	Minify valid JSON

Tool names and schemas are defined per plugin. Always use tinker tools <plugin> for the source of truth.

Direct tool calls

Best for scripting and one-shot agent actions:

tinker call <plugin> --tool <name> [--args '<json-object>']

• --args must be a JSON object (default {}).
• Results print as plain text or JSON depending on the tool.
• The plugin must already be running (tinker open <plugin>).

tinker open json-editor
tinker call json-editor --tool set --args '{"content":"[1,2,3]"}'
tinker call json-editor --tool format
tinker call json-editor --tool get

Stdio MCP server

For MCP clients that manage their own tool discovery and sessions:

tinker mcp <plugin>

Configure the client to launch tinker mcp <plugin> with stdio transport. The server:

1. Fetches tool definitions from the installed plugin package.
2. Exposes them via MCP listTools.
3. Forwards callTool requests to the running plugin over Tinker IPC.

Start the plugin before the MCP client connects:

tinker open json-editor
# MCP client config or separate terminal:
tinker mcp json-editor

If Tinker is not running, start it first (the CLI auto-launches on other commands, but mcp needs an active IPC connection).

Common workflows

Automate a plugin end to end

tinker list
tinker open json-editor
tinker tools json-editor
tinker call json-editor --tool set --args '{"content":"{\"a\":1}"}'
tinker call json-editor --tool format
tinker call json-editor --tool get
tinker close json-editor

Wire a plugin into an MCP client

1. Run tinker list and pick a plugin tagged [mcp].
2. Add an MCP server entry: command tinker, args ["mcp", "<plugin>"] (short name is fine).
3. Before using tools from the client, open the plugin: tinker open <plugin>.
4. Keep Tinker running while the MCP session is active.

Recover from a stale plugin state

tinker restart <plugin>
tinker tools <plugin>
tinker call <plugin> --tool <name> --args '{}'

When MCP is not available

Not every plugin defines tinker.mcp.tools. If tinker list shows no [mcp] tag, or tinker tools <plugin> / tinker call returns does not support MCP, MCP commands cannot automate that plugin. Use the debug skill instead:

tinker skills path debug    # load full debug skill, then read SKILL.md

The debug workflow opens the plugin and controls it through the Electron renderer via Chrome DevTools Protocol:

tinker open <plugin> --remote-debugging-port=9222   # if CDP is not already enabled
tinker open <plugin>

agent-browser connect 9222
agent-browser tab
# switch to the plugin://tinker-<name>/index.html tab (not the localhost shell tab)
agent-browser tab t2
agent-browser snapshot -i
# click, fill, screenshot, etc. — see the agent-browser skill

When to prefer each approach:

Situation	Approach
Plugin tagged [mcp] in tinker list	MCP: tinker tools, tinker call, or tinker mcp
No [mcp] tag or "does not support MCP"	Debug: tinker open + agent-browser on the plugin:// tab
Need stable, schema-defined automation	Add MCP tools to the plugin, or use an [mcp] plugin
One-off interaction with any running plugin UI	Debug skill

Load the debug skill before driving the UI; it covers tab selection (plugin:// vs the outer shell), CDP connection recovery, and interaction commands.

Command reference

Command	Description
tinker tools <plugin>	List MCP tools and input schemas
tinker call <plugin> --tool <name> [--args <json>]	Invoke one MCP tool
tinker mcp <plugin>	Start stdio MCP server for a plugin

Supporting lifecycle commands (from the core skill):

Command	Description
tinker list	Find plugins tagged [mcp]
tinker open <plugin>	Start plugin (required before tool calls)
tinker ps	Verify plugin is running
tinker restart <plugin>	Reset a stuck plugin

Troubleshooting

Plugin is not running. Please start it first: tinker open <name> — Run tinker open <plugin> before call or before the MCP client invokes tools.

<name> does not support MCP — The plugin has no tinker.mcp tools. Either pick a [mcp] plugin from tinker list, or load the debug skill and automate via tinker open + agent-browser (see When MCP is not available).

Unknown tool "..." — Run tinker tools <plugin> for valid tool names.

Failed to connect to Tinker / Tinker is not running — Start the Tinker app, then retry. mcp and call require the main process IPC socket.

Tool call returns an error string — Check --args matches the tool's inputSchema from tinker tools. Many tools require specific property names (e.g. content for set).

MCP client lists tools but calls fail — The plugin window may have been closed. Run tinker ps and tinker open <plugin> again.

Working safely

• MCP tools run inside the user's Tinker session with their data and permissions.
• Do not pass secrets on the command line if shell history matters.
• Read tinker tools <plugin> before calling unfamiliar tools; some operations replace or mutate user data immediately.
• Confirm the target plugin with tinker list before destructive calls.