Get an icon

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

Annotations already declare read-only, idempotent, non-destructive, open-world behavior, and the description adds genuinely new context: the payload includes a visible PNG, an alias parent is surfaced only when the name is an alias, and snippets default to currentColor. That goes beyond the annotation set without contradicting it.

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 identification rule and the returned-field inventory are front-loaded, and the closing sentence routes to the sibling. The middle snippet enumeration is list-like and slightly padded, but every sentence still carries actionable information.

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 seven parameters, the description does the work of describing the response shape (dimensions, collection, license, alias parent, URL, snippets, PNG) and calls out the visible image. Nothing essential for a correct single call 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 the baseline is 3. The description restates the currentColor behavior and enumerates snippet formats that the schema enum already lists, adding little meaning the schema does not already carry.

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 starts with a specific verb and resource ('Get one icon') and pins down the identifier format ('by Iconify id (prefix:name)'), which immediately separates it from search_icons and list_collections. It also names the panel of returned fields, so an agent knows exactly what kind of result to expect.

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?

"Use preview_icons to compare several icons" gives an explicit alternative with the condition that selects it (multiple icons vs. one). It does not mention when to prefer search_icons or get_collection, so the routing is clear but not exhaustive.

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