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

Annotations already cover read-only, idempotent, non-destructive, and closed-world traits, and 'Read-only' merely repeats them. The description goes further by disclosing the return shape (matches with paths, one composite image ordered left-to-right then down) and the fallback behavior when nothing matches (it lists the categories).

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 usage condition is front-loaded and the return behavior follows, so it reads in the right order with no preamble. It is a dense run-on paragraph with a few expendable asides ('and more (a few thousand pieces)'), which keeps it short of a 5.

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, the description carries the return-format burden and does so: paths, image, ordering, and the no-match category list. Pagination or the significance of limit beyond the schema default is not addressed, but nothing critical for a correct invocation is missing.

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 query, limit, and category are all documented in the schema with examples and defaults. The description adds only the implicit reinforcement of 'best matches' ordering, which the schema's limit field already states, so 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?

The description names a specific verb (search) and resource (the appdesigns library of ready-made pieces) and enumerates the asset classes it covers (SF Symbols, emoji, 3D shapes, badges, marks). It also distinguishes itself from siblings by positioning create_design and edit_asset as downstream consumers of the returned paths rather than alternatives.

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?

It gives an explicit triggering condition: use this when a design or saved asset needs a ready-made piece rather than art you draw, which implicitly rules out the drawing/creation path. However, it never names the sibling it replaces for custom art nor when to prefer get_asset, so there are no explicit exclusions or named alternatives.

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