compare_to_reference

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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so safety is covered. The description adds real behavioral detail beyond that: grid draws u/v coordinate lines every 0.1 (thicker at u=0.5) on the front/back panels, and cropping follows jersey_only. It does not describe the response shape, but the rendering behaviour is well disclosed.

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?

Every sentence carries information, but the prose is informal and meandering, and the opening is a sentence fragment rather than a front-loaded statement of purpose. It is longer than it needs to be for the payload it delivers.

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 7 parameters, 0% schema coverage and no output schema, the description does enough to call the tool correctly: it covers view, grid, cropping and reference input. The unexplained required 'kit' parameter and the 'body' parameter leave a small gap, but overall it is fit for purpose.

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%, so the description carries the burden and mostly does: it explains view selection, jersey_only cropping, grid default and what the lines mean, and the two reference-input modes (path vs base64). Only kit (required) and body ('male') are left unexplained, which keeps it from a 5.

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 states a concrete action: rendering the user's reference picture beside the kit on the game's rider from a matching angle to spot differences. It is clearly distinguishable from siblings like render_sheets or preview_kit. The opener is a grammatical fragment, but the resource and intent are unambiguous.

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 tells the agent when to use it (to spot what differs — colours, panel/logo placement, sizes) and how to choose the view ('pick the view nearest the reference's angle'). It also gives an explicit fallback when bytes cannot be sent (leave the reference out). No sibling is named as an alternative, so it stops short of a 5.

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