Where is my toolset saved?
The Save button writes one toolset to IndexedDB in the current browser. It is not uploaded to a workspace, and clearing site data removes it.
Where does JavaScript execute?
Script tools execute locally in Postman Sandbox with cookies, vault, datasets, visualizer, and execution APIs disabled. Static-response tools return their configured JSON locally.
What is sent to AI?
When you send a Playground prompt, selected tool names, descriptions, schemas, model-generated arguments, tool results, the system prompt, and conversation text participate in the request. The JavaScript source itself is not sent as a tool definition.
Can I design MCP tools with this tool?
Yes. You can define MCP tool names, model-facing descriptions, JSON Schema inputs, and JavaScript or static-response implementations, then test how an AI calls them. This browser tool does not start an MCP server; a Postman toolset can add a local MCP server when you are ready to expose the tools to an MCP client.
Does it start a local MCP server?
No. This signed-out browser tool does not expose a server, URL, port, client configuration, or server logs. In Postman, you can collaborate on and share the toolset, then run it as a local MCP server.