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

With no annotations, the description carries the full behavioral disclosure burden and does so thoroughly: ZIP is not inlined, URL expires in ~24 hours, automatic mode is paid and variable, 400 on no detection, panels are cropped not resized, jpeg/webp use quality 90, 20 calls/hour/IP, third-party URLs rejected, and REST upload is required first.

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 dense and every sentence carries useful information, with the core purpose front-loaded. However, it is a long single paragraph that could be more scannable if modes, limitations, and rate limits were split into bullets, though the length is largely justified by the number of critical caveats.

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 no annotations and no output schema, the description is exceptionally complete: it covers return format, retention, failure behavior, cost, variability, rate limiting, input restrictions, and the upload flow. Almost nothing an agent needs to invoke the tool correctly is left to guesswork.

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?

The schema already documents all three parameters, and the description adds meaningful semantics: rows/cols only take effect together, omitting both enables automatic detection, and format defaults to lossless PNG with quality-90 lossy options. The description also mentions passing 'fileUrl' even though that parameter is absent from the schema, which is a minor inconsistency.

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 opening sentence states a specific verb and resource: cut a storyboard, collage, or grid image into separate panels and return them as a ZIP in reading order. It also explicitly distinguishes itself from compress_image by saying it does not shrink a file and cannot take a PDF apart.

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 gives explicit mode-selection guidance: provide both rows and cols for a deterministic free division, or omit both for vision-based detection with tradeoffs. It names compress_image as the alternative for shrinking files and states the paid-compute rate limit and upload prerequisite.

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