render_preview

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

With readOnlyHint=true already covering the safety profile, the description adds genuinely useful behavior the annotation cannot: nearest-neighbor upscaling, checkerboard transparency, and grid layout in frame order. It still says nothing about size limits, backend fallback behavior, or cost of rendering many frames.

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 tight sentences with no waste; the rendering behavior is front-loaded and the call-to-action follows. Every clause carries information.

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 13-parameter tool with no output schema, describing the returned image is valuable and mostly compensates for the missing output schema. However, the description never disambiguates the overlapping selection modes (frame vs frames vs from/to vs tag), which is the main usability gap given the parameter complexity.

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 coverage is 85%, so the schema already documents nearly every parameter including the backend enum and crop object. The description only loosely connects to parameters via 'laid out in a grid in frame order' (columns/frames). Baseline 3 is appropriate when the schema does the heavy lifting.

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?

The description gives a specific verb and resource ('renders frames as an image you can look at') and clarifies the render style, distinguishing it from file-producing siblings like export or export_sprite_sheet. It stops short of explicitly naming an alternative tool, so it lands at 4 rather than 5.

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?

'Use this after edits to check the result' supplies clear situational context for when to reach for this tool. There are no exclusions or named alternatives (e.g., vs. export), so it clears the 'clear context, no exclusions' bar but not the top tier.

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