Read Image Crop

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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds genuinely useful behavior beyond that: the crop is 'rendered at a safe maximum longest side of 1600 px' (so output may be downscaled) and coordinates are 'original-image pixels from the top-left corner.' No contradiction with annotations.

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 sentences with zero waste: purpose first, then the two critical constraints (rendering cap and coordinate frame). Every sentence earns its place and nothing is redundant with the schema.

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 7-parameter tool with no output schema, the description covers purpose, coordinate system, and rendering cap, but omits out-of-bounds behavior and any guidance on how this tool relates to read_image and read_image_tile. An agent can invoke it correctly, but the sibling selection context is left unresolved.

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%, so the baseline of 3 applies. The description adds the 'from the top-left corner' origin clarification and the 1600 px cap context for max_dimension, but most parameter semantics (x/y/width/height in original-image pixels) are already fully documented in the schema, making the description's additive value modest.

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 names a specific operation ('Read a rectangular crop directly from the original image') with a clear resource and scope. 'Rectangular crop' plus 'directly from the original image' separates it from sibling tools like read_image and read_image_tile without needing to open their schemas.

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 implies when to use it — when a rectangular region of the original image is needed — but it never names read_image or read_image_tile as alternatives, and gives no explicit when-not-to-use guidance. Usage context is inferable rather than stated.

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