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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds the return behavior: 'Returns matching emojis with names and groups,' which is useful context beyond the annotations. It does not contradict any annotations, and the additional information is relevant and non-redundant.

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?

The description is a single, concise sentence that front-loads the action and provides examples inline. There is no fluff or repetition; every word contributes to the tool's purpose and usage. It is perfectly sized for the tool's simplicity.

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?

Given the simple nature of the tool (one parameter, output schema present, detailed annotations), the description is sufficiently complete. It states the return format and provides example inputs. It does not explain pagination or sorting, but such details are not critical for a simple search-by-category operation. The combination of annotations, schema, and description covers the essential context.

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 input schema already provides 100% coverage for the 'category' parameter, including a descriptive text and examples. The description adds a few more example categories but does not fundamentally expand parameter understanding beyond what the schema already provides. With high schema coverage, the baseline of 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?

The description clearly states the tool's purpose: searching emojis by category. It uses a specific verb ('Search') and resource ('emojis'), and provides concrete examples of valid categories, which disambiguates it from sibling tools like get_by_group or random_emoji. The scope is well-defined.

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 implies usage for retrieving emojis filtered by a category, but it does not explicitly state when to use this tool versus alternatives like get_by_group or random_emoji. There are no exclusion criteria or alternative recommendations, leaving the decision to the agent's inference.

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