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

Annotations already declare readOnlyHint, openWorldHint, and destructiveHint, covering the safety profile. The description adds useful behavioral context: it mentions 'live guide counts' and emphasizes machine-readable output rather than prose, giving the agent a clearer picture of what the result will contain and how it is produced.

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?

A single, dense sentence with no filler. The core purpose is front-loaded, and every additional phrase contributes useful specifics about the vocabulary contents and the machine-readable nature of the response.

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 zero parameters, an output schema, and read-only annotations, the description fully covers what an agent needs to know. It explains the resource, the contents, and the output form without requiring the agent to infer anything critical.

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 has zero parameters, so schema semantics are trivially complete. The description adds value by enumerating the response categories, which helps the agent understand what data the output schema represents. No parameter documentation is needed.

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 states a clear verb-resource pair: 'Get the bicycle.guide vocabulary'. It enumerates the specific categories returned (domains, shelves, series, personas, guide_types, classification conventions), which clearly distinguishes this from siblings like list_guides or get_guide.

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 makes clear this is the tool for retrieving vocabulary/taxonomy as machine-readable data, as opposed to prose documentation. It does not explicitly mention when not to use it or name alternative tools, but the context is strong enough for an agent to select it appropriately.

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