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

Annotations already declare readOnlyHint/idempotentHint/non-destructive, but the description adds real behavioral context: it is free ('costs nothing'), it surfaces a quota ('how much avatar time is left'), and it is gated to Premium and Ultimate tiers. It does not describe output shape or error behavior, which keeps it short of a 5.

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?

Front-loaded with the core verb+resource and the when-to-call rule in the first two sentences. The later sentence about in-app panels and website Avatar Packs is context rather than instruction, which is slightly more than strictly required, but it is not bloated.

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 no parameters and no output schema, the description carries the return content ('presenters, and how much avatar time is left') implicitly and covers prerequisites, cost, and tier gating, so an agent can call it correctly without more information.

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, so the baseline is 4 and no description-side parameter guidance is needed. Nothing here misleads about inputs.

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?

States a specific verb and resource: it lists the user's AI presenters and remaining avatar time. It also disambiguates from neighbors like list_characters, make_presenter, and draw_presenter by naming the creation path explicitly ('New presenters are made right here with draw_presenter').

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?

Gives explicit trigger conditions: 'Call it before putting a presenter in a video, or when the user asks who their presenters are or how much avatar time they have.' It also routes related work to siblings (draw_presenter for creation, Avatar Pack for top-ups).

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