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

Annotations provide no positive hints (all false), so the description carries the behavioral burden. It discloses output naming, aspect-ratio preservation, width/height relationship, and the 5-file/4MP limit. It does not restate safety properties, but nothing contradicts the 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?

Three sentences, no filler, with the core command front-loaded and supporting constraints packed efficiently. Every sentence earns its place.

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 description covers the main behavior, naming, sizing rules, and quotas, while the schema covers path/out_dir semantics. A minor gap is that width/height are optional in the schema and the description never states what happens when neither is provided.

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 100% schema coverage, the description need not repeat parameter names, but it adds genuinely new semantics for the width/height interaction—'one lets the other follow' and 'both fit inside the box'—which is not inferable from the schema alone.

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 opens with a specific verb and resource—'resize every image in paths at once'—and adds the output naming pattern, making the batch behavior unmistakable. This distinguishes the tool from sibling image_resize without needing the schema.

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?

It clearly states when to call the tool: when all images in paths should be resized in one operation. It does not explicitly name alternatives like image_resize for single-image jobs or give when-not-to-use conditions, but the batching context is unambiguous.

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