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

No annotations are provided, so the description carries the full burden. It does disclose scope by enumerating exactly which features are covered (View Transitions, scroll-driven animations, linear(), @starting-style, Web Animations API), which is real behavioral information. However it says nothing about the shape of the response, freshness of the compatibility data, or whether coverage is partial, leaving meaningful gaps for an informational tool.

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 compact sentence with the feature enumeration front-loaded and no padding. The bracketed category prefix is slightly redundant meta-text, but nothing else wastes space.

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 and no annotations, the description must explain what comes back. It communicates the topic and the covered features but not the return form (browser-by-browser version table, baseline status, or note), so an agent can pick the tool correctly yet not know what to expect from the call.

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 and schema coverage is 100%, so there is nothing for the description to disambiguate. Baseline 4 applies for a no-parameter tool.

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 names the resource (browser support versions for five specific web animation features) and enumerates the covered features, so scope is visible. But there is no clear verb — it never says whether it returns a per-browser support table, baseline dates, or general guidance — and the bracketed category tag '[Web Animation Toolbox]' substitutes for a definition rather than supplying one. It is viable but vaguer than a 4 requires.

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?

No when-to-use, when-not-to-use, or alternative is given. Siblings such as motion__compare_animation_libraries, motion__animation_a11y_checklist, and motion__generate_easing exist and are never mentioned, so an agent must infer from the feature list alone that this is the browser-compatibility lookup.

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