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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered; the description usefully adds what the payload contains (code snippets per framework, signed download link, licence note) and that it also covers movements and voice. The IDE instruction implies the agent must write files itself, which is meaningful behavioral context beyond the annotations. Missing only limits (rate/cost/size) and whether the .ania link expires.

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?

Purpose is front-loaded and every clause adds a distinct artifact or condition; "Free" is a short, load-bearing qualifier. The single sprawling sentence with stacked parentheticals makes it dense to scan compared with a short bulleted structure, but there is no filler.

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 only 3 fully described parameters, no output schema and annotations covering safety, the description does the remaining work: what is generated, for which stacks, and how to apply it in an IDE. The one residual gap is what the caller should do when avatarId refers to an unfinished job, which the schema only hints at.

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%, so the baseline is 3. The description mentions the user's avatar and lists the framework options, but those simply restate the enum and the avatarId/language params are not elaborated beyond what the schema already says.

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 ("Step-by-step install of the user's avatar into a website") and enumerates the concrete artifacts produced: framework code for React/Vue/Svelte/Angular/HTML/WordPress, movement and voice code, a signed .ania download link with curl, and the licence note. That is enough to distinguish it from generic retrieval tools like get_avatar or download_avatar 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?

"In IDE clients (Cursor, Claude Code, VS Code…) apply it directly to the project" gives a clear conditional on how/when to use the output, and "Free" signals no cost barrier. It stops short of naming an explicit alternative or exclusion (e.g. when to prefer download_avatar instead), so it is not a full routing statement.

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