Render a full-resolution crop of the framed picture, including grain and halation, to inspect fine detail at 100% before exporting.
Render a full-resolution crop of the framed picture with grain and halation, to inspect fine detail at 100%.
| Name | Required | Description | Default |
|---|---|---|---|
| size | No | Crop size as a fraction of the frame, 0.02-1. | |
| center_x | No | Horizontal center of the crop, 0 = left edge, 1 = right edge. | |
| center_y | No | Vertical center of the crop, 0 = top, 1 = bottom. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must carry the behavioral load. It usefully discloses that the crop includes grain and halation (i.e. the processed look, not raw source pixels) and that it renders at full resolution, but it never states that the operation is non-destructive, whether a full-res render is expensive/slow, or what the response actually contains.
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?
A single sentence with the verb and resource front-loaded and no wasted wording; nothing to trim.
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?
The tool is simple (three optional, defaulted numeric parameters), and the description covers what is produced. However, with no annotations and no output schema, the return value (image payload vs. reference) and the cost of a full-resolution render are left unexplained.
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% and each of size/center_x/center_y is documented with defaults and coordinate conventions, so the schema does the heavy lifting. The description adds only the notion of cropping from 'the framed picture', not any meaning about how size or center interact.
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?
Specific verb ('Render') plus a precise resource ('a full-resolution crop of the framed picture') and an explicit rationale ('to inspect fine detail at 100%'). It is clearly distinct from develop, frame, export and undo, though it never names a sibling it could be confused with (compare is the nearest candidate).
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?
The trailing clause gives a clear use context: inspect fine detail at 100% magnification. It stops short of exclusions or alternatives, so an agent is not told when to prefer this over compare or export, but the intended situation is unambiguous.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.