editor_evaluate_expression
Evaluate a GDScript expression in debugger/editor context.
This record as markdown: /tools/yanhuifair-godot-mcp/editor-evaluate-expression.md
What editor_evaluate_expression does on Godot
AI agents invoke editor_evaluate_expression to trigger actions in Godot. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
| Parameter | Type | Required | Description |
|---|---|---|---|
expression | string | Yes | GDScript expression to evaluate |
Parameters from the server's own tool schema.
Why editor_evaluate_expression is rated High
This tool executes arbitrary GDScript code in the Godot editor/debugger context. Evaluating arbitrary expressions can trigger file system operations, spawn processes, modify project state, or cause other side effects depending on the expression provided. This is code execution, and misuse could have broad impact on the Godot project or host system.
From the tool's definition "Evaluate a GDScript expression in debugger/editor context"
Risk signalsAccepts freeform code/query input (expression)
Attacks that exploit this kind of access
The rule that runs editor_evaluate_expression safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Godot, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For editor_evaluate_expression, this is the rule to start with:
editor_evaluate_expression stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Godot, apply this rule, and every editor_evaluate_expression call is checked against it from then on.
Questions about editor_evaluate_expression
Evaluate a GDScript expression in debugger/editor context. It is categorised as a Execute tool in the Godot MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
editor_evaluate_expression accepts 1 parameter: expression. Required: expression. The full parameter table on this page comes from the server's own tool schema.
Register the Godot MCP server in PolicyLayer and add a rule for editor_evaluate_expression: 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 Godot. Nothing to install.
editor_evaluate_expression is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the editor_evaluate_expression 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 editor_evaluate_expression. 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.
editor_evaluate_expression is provided by the Godot MCP server (@yanhuifair/godot-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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