main_screen_set
Switch the editor's main-screen tab (2D / 3D / Script / …), matching the name case-insensitively. Use this before screenshot_editor to make the viewport you want to capture the active one — opening a scene does NOT switch the tab. Returns the resulting state, read back from the editor rather than...
This record as markdown: /tools/breakpoint-mcp/main-screen-set.md
What main_screen_set does on Breakpoint
AI agents use main_screen_set to create or update resources in Breakpoint, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Breakpoint environment.
| Parameter | Type | Required | Description |
|---|---|---|---|
name | string | Yes | Tab name as the editor reports it, case-insensitive — e.g. "2D", "3D", "Script" |
Parameters from the server's own tool schema.
Why main_screen_set is rated Medium
An AI agent can call main_screen_set faster than any human can review: one bad instruction and it creates or modifies resources in Breakpoint by the hundred, each call as confident as the last.
Attacks that exploit this kind of access
The rule that runs main_screen_set safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Breakpoint, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For main_screen_set, this is the rule to start with:
main_screen_set stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Breakpoint, apply this rule, and every main_screen_set call is checked against it from then on.
Questions about main_screen_set
Switch the editor's main-screen tab (2D / 3D / Script / …), matching the name case-insensitively. Use this before screenshot_editor to make the viewport you want to capture the active one — opening a scene does NOT switch the tab. Returns the resulting state, read back from the editor rather than echoed. An unknown name comes back with the live list of available tabs. It is categorised as a Write tool in the Breakpoint MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
main_screen_set accepts 1 parameter: name. Required: name. The full parameter table on this page comes from the server's own tool schema.
Register the Breakpoint MCP server in PolicyLayer and add a rule for main_screen_set: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Breakpoint. Nothing to install.
main_screen_set is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the main_screen_set rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for main_screen_set. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
main_screen_set is provided by the Breakpoint MCP server (breakpoint-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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