Capture a read-only Three.js screenshot marked with object names at their screen positions to inspect scene layout.
[INSPECT] Read-only. Screenshot with object names drawn at their screen positions ([M]esh, [L]ight, [G]roup, [C]amera). Best for understanding layout.
| Name | Required | Description | Default |
|---|---|---|---|
| width | No | Width in pixels (default: canvas width) | |
| height | No | Height in pixels (default: canvas height) |
Changes observed during successful MCP inspections.
v0.5.0Input schema / additionalPropertiesRemoved value: -falseInput schema / properties / height / descriptionPrevious value: -"Height in pixels"New value: +"Height in pixels (default: canvas height)"Input schema / properties / width / descriptionPrevious value: -"Width in pixels"New value: +"Width in pixels (default: canvas width)"v0.4.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description still earns credit for disclosing what the returned artifact actually contains (an image with [M]/[L]/[G]/[C] markers overlaid at object screen positions), which is real output-content information not present in any structured field. It stops short of stating the return format (image vs. path/URL) or any size limits.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two short lines, front-loaded with the [INSPECT] Read-only tag followed immediately by the tool's distinguishing behavior. Every clause earns its place; the only redundancy is restating read-only, already covered by annotations, which is negligible.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a zero-required-parameter read-only screenshot tool with full schema coverage and rich annotations, the description supplies the missing piece — what the image contains. Without an output schema it could go one step further and state the return format (inline image vs. file path), which is the only remaining gap.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100% with both width and height documented as pixel dimensions defaulting to canvas size, so the schema carries the full burden. The description adds nothing about the two parameters, which is the correct baseline when the schema is complete.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb+resource (screenshot with object names drawn at screen positions) and goes further by decoding the annotation glyphs ([M]esh, [L]ight, [G]roup, [C]amera), which no sibling schema reveals. That labeling scheme plus the [INSPECT] tag lets an agent distinguish it from take_screenshot and capture_frames without opening either schema.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
'Best for understanding layout' implies a use case and a contrast with plain screenshots, but no alternative tool is named and no when-not condition is given. The routing signal is inferable rather than explicit, so this is minimum-viable guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.