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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so the description does not need to repeat those safety traits. It adds useful context beyond the annotations: the tool requires the person's AI Anyone account, may trigger a first-time sign-in, and returns only that user's own characters as a grid. It does not contradict any annotation.

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 front-loaded with the primary use case and examples, then follows with authentication and return-shape context. It is slightly repetitive with 'AI Anyone' but remains appropriately sized for the tool's complexity.

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 the simple one-parameter schema and rich annotations, the description covers the main invocation context: when to use it, sign-in requirements, scoping to the user's own characters, and a basic return format. Because there is no output schema, it could say more about the character grid contents, but it provides enough for correct selection and invocation.

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 has one optional page parameter with 100% description coverage, so the schema already explains that it controls pagination in groups of 24. The description does not add any additional meaning about pagination beyond what the schema provides. With full schema coverage, the baseline score of 3 is appropriate.

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 specific retrieval action and resource: getting the characters the user made themselves on AI Anyone. It explicitly scopes the result to 'their own characters' and provides example utterances, which clearly distinguishes this from sibling tools that call or speak as people. An agent can identify the tool's purpose without opening the schema.

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 gives clear usage context with example phrases like 'show my characters' and 'open the character I made,' which tells an agent when to call it. It does not explicitly name alternatives or state when not to use it, so it falls short of the full when/when-not/alternatives standard.

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