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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds meaningful behavior beyond the annotations by stating that authentication is required and clarifying the scope ('the user's design collections') and included counts. No contradiction with 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?

Two short sentences with no redundancy. The primary action and resource are front-loaded, and the authentication requirement is a necessary addition. Every word contributes to understanding the tool.

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 list operation with one optional parameter, an output schema, and strong safety annotations, the description covers all essentials: what is listed, whose collections, what metrics are included, and the authentication prerequisite. Nothing critical is missing.

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 100%: the single optional parameter `limit` is fully documented in the schema with its default behavior. The description does not add additional parameter semantics, so the baseline of 3 is appropriate; the schema already carries the needed meaning.

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 uses a specific verb 'List' with a clear resource ('the user's design collections') and specifies exactly what is returned ('session counts and asset counts'). This clearly distinguishes it from sibling tools like generate_* and check_credits, so an agent can correctly differentiate it without additional investigation.

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 conveys the core use case and notes that authentication is required, which is a useful prerequisite. However, it does not explicitly state when to use this tool versus alternatives or when not to use it. Usage is implied by the clear contrast with generation and status-check siblings, but no explicit routing is provided.

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