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

Annotations already declare readOnly, non-destructive, closed-world behavior, and the description adds genuinely new context: the link is signed, expires in roughly 15 minutes, and the operation is free. The expiry window is the kind of operational detail an agent needs to act promptly, though nothing is said about failure modes for expired or invalid avatar ids.

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?

A single dense sentence that front-loads the core deliverable (signed download link) before the secondary usage note. No filler, though the 'with what to do with it' phrasing is slightly informal for a tool definition.

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 output schema, the description correctly carries the burden of describing the return value (a signed, time-limited URL) and notes the cost is free. For a two-parameter read tool this is nearly complete; only error/expiry handling is unaddressed.

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%, with avatarId documented as coming from meus_avatares or a finished job and language as a BCP-47 tag. The description adds no parameter-level meaning beyond that, so the baseline 3 applies.

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: a signed download link for the user's .ania avatar file. It is clearly a download/retrieval tool, but it never names or contrasts with siblings like get_avatar or show_avatar, so the agent must infer the distinction.

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 parenthetical about opening in Ania Player or putting it on a website describes what to do after downloading, not when to choose this tool over get_avatar or show_avatar. Usage is implied by the purpose but no explicit when/when-not guidance is given.

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