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

Annotations cover the safety profile, but the description goes well beyond them: it discloses the five-minute cache, the bundled-snapshot fallback, the origin/fallbackReason provenance markers, the distinction between content provenance and transport origin, and the failure mode when no tokens exist. That is exactly the extra behavioral context annotations cannot provide.

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 in the first clause, followed by well-separated Args/Returns/Examples sections. It is somewhat long for a one-parameter tool and the 'Content provenance is distinct from transport origin' aside is a little verbose, but every section carries signal.

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 an output schema present, the description need not detail return values, and it still supplements them with provenance and fallback semantics. Combined with annotations and examples, an agent has everything required to call this correctly, including the error case.

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% and the single 'slug' parameter is already documented in the schema; the description's arg line ('style identifier') restates it with only marginally more meaning. With the schema doing the heavy lifting, baseline 3 is appropriate.

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 (Get) and resource (a style's design tokens) and enumerates the token categories (border, shadow, typography, spacing, semantic colors, forbidden/required classes), which cleanly separates it from the broader stylekit_get_style sibling. An agent can identify exactly what payload this returns 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?

The two examples ('give me the spacing and border tokens for bento-grid') imply usage and the error condition ('no tokens registered') gives a hint about preconditions, but the description never states when to prefer this over stylekit_get_style or the other stylekit_get_* siblings. Usage is implied rather than asserted.

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