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

Annotations already declare readOnly, idempotent, non-destructive, and not-open-world, so the safety profile is fully covered. The description adds useful context that this concerns the 'public' form and that manual request workflows are separate from automated generation, but it says nothing about the returned content, since there is no output schema.

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, all load-bearing: purpose, exclusion with named alternatives, and positive routing to sibling read tools. Front-loaded and waste-free.

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 zero-parameter, no-output-schema info tool, the description supplies enough to select and call it correctly, and annotations carry the safety profile. The only minor gap is that it does not enumerate the actual form fields or limit values, though that is reasonably left to the tool's response.

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 tool takes zero parameters (empty object schema, 100% coverage), so there is nothing for the description to disambiguate. Baseline 4 applies for a parameterless tool.

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 conveys the resource (pet request form fields and reference image limits) and its nature as a read-only info lookup, distinguishing it from generate_pet, get_pet_generation, search_pets, and get_pet. It is phrased obliquely through 'Use when the user wants...' rather than a direct declarative statement of what the tool returns, so it is clear but not maximally crisp.

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?

Explicit when-to-use ('request a new Codex pet or understand the public request form fields'), when-not-to-use ('Do not use to create, submit, update, or inspect private generation requests'), and named alternatives (generate_pet, get_pet_generation, search_pets, get_pet). Nothing about routing is left to inference.

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