getImageDimensions

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

Annotations already indicate readOnly, idempotent, and openWorld. The description adds that it does not proxy to BD, performs a Range GET of first 64KB, and returns error for unsupported formats, providing full behavioral context beyond 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?

The description is well-structured with clear sections (purpose, caller contract, see also) and is front-loaded. It is informative but slightly verbose due to the caller contract and rule references; still efficient overall.

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?

Despite no output schema, the description specifies return fields (width, height, format, aspect_ratio, orientation) and error response format. It covers error handling, limitations, and usage context, making it fully complete for an agent to use correctly.

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 single 'url' parameter has 100% schema coverage with description, and the description adds crucial context: requires HTTP 200/206 for Range request, example format, and that it should be a bare canonical URL. This fully explains the parameter's requirements.

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 it probes an image URL and returns dimensions + orientation, specifying it parses JPG/PNG headers via a Range GET. This distinguishes it from sibling tools, which are mostly CRUD operations on different entities.

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 explicitly states it is used by content-creation skills for image orientation verification, provides a caller contract to filter URLs to .jpg/.jpeg/.png, and warns about unsupported formats with error fallback. References to 'Rule: Image dimensions' and 'Rule: Image dedup' give further context.

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