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

With no annotations, the description must disclose behavior. It explains the calculation steps (simplify ratio, solve for height) and provides an example output format ('16:9'), but it does not describe the exact return structure, rounding behavior, or edge cases. The title's 'Crop' is not mentioned in the description, creating minor ambiguity.

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 concise at two sentences, front-loading the purpose and following with actionable instructions. The first sentence partially echoes the title ('Aspect Ratio Calculator (Resize & Crop)'), but it adds the key behavior 'resize while keeping it', so it 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?

For a simple calculator with no output schema and no annotations, the description covers the core resizing workflow well. However, it omits the 'Crop' functionality hinted in the title and does not specify the output format beyond an example, leaving some context incomplete.

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 0%, but the description compensates by clarifying the roles: width and height are the original dimensions, newWidth is the desired new width, and it explains the relationship between them. This adds meaning beyond the bare schema, which only lists them as numbers.

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 the tool simplifies an aspect ratio and computes a matching height for a new width, with a concrete example ('16:9'). It specifies the resource (aspect ratio) and the verbs (simplify, resize), but does not explicitly distinguish it from siblings like crop_factor_calculator or print_resolution_calculator.

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 instructional context: enter width and height to get the ratio, then enter a new width to find the matching height. However, it does not state when to use this tool versus alternative calculators, nor mention any exclusions or prerequisites.

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