Crop a source

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

Annotations already indicate readOnlyHint=false and destructiveHint=false, so the description adds useful context by clarifying that crop pixel values are absolute to the source's native resolution (not the canvas) and that format omitted applies to both canvases. However, it does not disclose whether the crop replaces existing crop settings, if the operation is reversible, or any side effects beyond the parameter semantics.

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?

The description is two sentences, front-loaded with the core action, and packs all essential parameter semantics compactly. Every sentence contributes meaningful information without redundancy or filler.

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?

Given 8 parameters, no output schema, and rich parameter interactions, the description covers the main parameters and important contexts (native resolution, canvas formats). It misses scene_id context and does not explain expected return behavior, but the core invocation criteria are sufficiently covered for a mutation tool.

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?

With schema description coverage at 0%, the description compensates well for six of eight parameters: left/right/top/bottom (absolute pixels of source native resolution), anchor (placement of retained region), and format (canvas scope). It omits scene_id and source_id, but source_id is self-evident and scene_id is optional and likely contextual. The explanation of pixel space and canvas scope adds critical meaning beyond the raw schema.

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 clearly states the action: 'Crop pixels off a source's edges.' It names the specific resource (source) and the operation (cropping), which is distinct from sibling tools like set_source_transform or set_source_shape. No ambiguity about what the tool does.

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 description does not provide any guidance on when to use this tool versus alternatives. It lacks explicit context like 'Use this when you need to remove edges' or exclusions/recommendations. The only usage-related hint is the parameter semantics for 'format', but that does not address tool selection.

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