list_libraries

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

With no annotations, the description carries the full burden. It discloses the return content (library info, popular icon sets, usage examples), which is useful behavioral context, but says nothing about the read-only nature, ordering, or size of the result set. Adequate but not rich.

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 short sentences, front-loaded with the purpose and followed by the workflow cue and return summary. 'with details' is slightly redundant against the explicit return list, but nothing is wasted.

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 must describe returns, and it does enumerate the key payload (library info, popular icon sets, usage examples). For a parameterless read-only listing tool this is sufficient, though pagination or result-size limits are unaddressed.

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 tool takes zero parameters, so the baseline is 4. There is no parameter syntax to explain, and the description correctly focuses on what the call returns instead.

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 and resource: 'List all available icon libraries with details,' clearly distinct from sibling tools like search_icons or get_icon. It does not explicitly name a sibling it differs from, but the listing framing is unambiguous.

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?

'START HERE to understand available icon sources' gives clear contextual guidance on when to reach for this tool first in the workflow. It stops short of naming when-not-to-use or explicit alternatives, but the entry-point framing is a strong usage signal.

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