Godot MCP Runtime

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start_profiler

Start a performance capture in the running Godot game and return control immediately. Keep playing the game while it records, then stop the capture to retrieve results.

Instructions

Start a profiler capture and return immediately, so simulate_input, run_script and screenshots can drive the game while it records. Requires run_project with profiling: true. Stops itself after seconds (default 30, max 60); call stop_profiler for the results. Returns: active, firstFrame, captureLimit, maxSeconds. Use profile_project instead for an unattended window. Errors if a capture is already running or profiling was not enabled at launch.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`seconds`	No	Maximum capture duration before the automatic stop, greater than 0 and at most 60 (default: 30).
`captureLimit`	No	Rows the engine puts in each frame packet, 16..512 (default: 512). Godot selects them by inclusive time, so a lower limit hides cheap functions and sets limitReached.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`active`	No
`firstFrame`	No
`maxSeconds`	No
`captureLimit`	No

Schema Changelog

Changes observed during successful MCP inspections.

Addedv3.4.0Sep 9, 2026

TDQS

A4.7/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description discloses key behaviors beyond the annotations: it returns immediately, stops itself after `seconds`, requires prior profiling setup, errors under specific conditions, and returns a defined set of fields. Annotations only say readOnlyHint=false and destructiveHint=false, so the description carries the behavioral burden and does so thoroughly.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact but information-dense. Every sentence earns its place: what the tool does, why it returns immediately, prerequisites, auto-stop behavior, related tools, return values, and error conditions. It is front-loaded with the core purpose and contains no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the full input schema and output schema, the description still adds essential context: how this tool fits into an interactive capture workflow, how to retrieve results, prerequisites, alternatives, and failure modes. An agent has everything needed to decide whether to call it and how to call it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Input schema coverage is 100%, so the schema already fully documents `seconds` and `captureLimit`. The description mentions `seconds` with its default and max, but this repeats the schema rather than adding new meaning. There is some value in listing returned fields, but that is output semantics rather than parameter semantics.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource: 'Start a profiler capture and return immediately.' It also differentiates itself from siblings by explicitly naming profile_project for unattended windows and stop_profiler for retrieving results, so an agent can distinguish it without opening other tool schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage conditions are explicit: it requires run_project with profiling: true, errors if a capture is already running or profiling was not enabled, and tells the agent to use profile_project instead for an unattended window. This is strong when-to-use and when-not-to-use guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.