mp_add_spawner
Add a MultiplayerSpawner node under a parent (undoable). Godot 4 high-level multiplayer replicates server-spawned nodes to clients: set spawn_path to the node whose children are auto-replicated, and register the scenes it may spawn. Pure node authoring — no service is started.
This record as markdown: /tools/breakpoint-mcp/mp-add-spawner.md
What mp_add_spawner does on Breakpoint
AI agents use mp_add_spawner 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 | — | Node name (default MultiplayerSpawner) |
spawn_path | string | — | NodePath (relative to the spawner) whose children are auto-replicated |
parent_path | string | Yes | Parent node path relative to the scene root; "." for the root |
spawnable_scenes | array | — | res:// scenes the spawner may instantiate (add_spawnable_scene) |
Parameters from the server's own tool schema.
Why mp_add_spawner is rated Medium
This tool creates and modifies a node in a game scene hierarchy (adding a MultiplayerSpawner), which is a write operation. It is explicitly undoable, so it does not qualify as Destructive.
From the tool's definition Tool name 'mp_add_spawner' and description stating 'Add a MultiplayerSpawner node under a parent (undoable)'. The description explicitly marks the action as 'undoable', indicating reversibility. The tool creates/modifies a scene node structure in Godot.
Attacks that exploit this kind of access
The rule that runs mp_add_spawner 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 mp_add_spawner, this is the rule to start with:
mp_add_spawner 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 mp_add_spawner call is checked against it from then on.
Questions about mp_add_spawner
Add a MultiplayerSpawner node under a parent (undoable). Godot 4 high-level multiplayer replicates server-spawned nodes to clients: set spawn_path to the node whose children are auto-replicated, and register the scenes it may spawn. Pure node authoring — no service is started. 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.
mp_add_spawner accepts 4 parameters: name, spawn_path, parent_path, spawnable_scenes. Required: parent_path. 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 mp_add_spawner: 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.
mp_add_spawner 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 mp_add_spawner 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 mp_add_spawner. 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.
mp_add_spawner 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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