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

Annotations already cover read-only, idempotent, and non-destructive behavior. The description adds valuable context beyond those annotations by explaining that these rules concern silent rendering failures, and noting the platform nuance ('on iOS, mostly native Liquid Glass'). This helps an agent understand the nature of the output without contradicting the 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?

Three sentences, each with a distinct purpose: defining the resource, explaining parameter use, and providing usage context. No filler or redundant phrasing; information is front-loaded and scannable.

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 read-only, two-optional-parameter tool with no output schema, the description is largely complete. It explains what the rules are, how to filter them, and when to consult them. It could mention the return shape (e.g., a list of rule descriptions), but the concept is clear enough for an agent to invoke correctly.

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 coverage is 100% and the schema already explains that slug/platform are optional and what omitting them means. The description largely restates this ('Pass a slug to scope them to one component, and a platform to get only the rules that hold there'), adding slightly more specificity about scoping to one component, but not enough to exceed the baseline 3.

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 clearly identifies the resource ('runtime rules for this catalog') and defines what those rules are ('the mistakes that make a component render blank or wrong with no warning, no error and no red box'). This distinguishes it from sibling tools like get_component or list_components, which operate on components/tokens rather than on runtime rendering behavior.

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 gives explicit usage context: 'Relevant before writing animation or layout code around one of these components.' It also explains optional scoping via slug and platform. However, it does not explicitly mention when not to use the tool or name alternative tools for comparison, stopping short of a full 5.

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