image_resize

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

Annotations already declare destructiveHint=true, idempotentHint=false, and readOnlyHint=false, so the bar is lower. The description adds useful behavior (aspect-ratio preservation, output format inferred from the extension), but says nothing about what happens when the output file already exists or how the 'overwrite' flag changes that, which is exactly the risk the destructive hint flags.

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?

Three short sentences, front-loaded with the operation and its main modes, then the two behavioral rules. Nothing redundant.

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?

With an output schema present, return values needn't be described, and the destructive annotation covers the risk profile. Still missing for a destructive 6-parameter mutation: overwrite semantics, mutual exclusivity of sizing parameters, and any error/validation guidance.

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 0%, so the description must carry parameter meaning; it partially does, explaining the roles of width, height, and percentage and the aspect-ratio rule. It leaves 'overwrite' undefined and never states precedence when width, height, and percentage are supplied together — a meaningful ambiguity for a 6-parameter tool.

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 and resource ('Resize an image') plus the three supported sizing modes, so the agent immediately knows the operation. It doesn't distinguish itself from near-siblings like image_thumbnail or image_convert, which is the only gap.

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?

Usage is implied by the behavioral rules ('keeps the aspect ratio when only one dimension is given', format from output extension), but there is no explicit when-to-use/when-not guidance and no mention of when image_thumbnail or image_convert would be preferred.

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