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

With no annotations, the description carries the transparency burden. It discloses that the tool returns a single category and related alternatives, which is useful behavioral context beyond the name. Still, it does not explain behavior for unknown slugs, whether alternatives are always present, or what 'in full' concretely includes.

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 sentence with no filler. It front-loads the core action ('one bus category in full') before the secondary behavior (related alternatives), and every phrase contributes to understanding the tool.

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?

The tool is simple with one parameter and a fully documented schema, so the description is serviceable for invocation. However, because there is no output schema, the description's vague 'in full' does not fully clarify what fields or structure the agent should expect, and unknown-slug behavior is 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?

Schema coverage is 100% and the slug parameter description already provides format examples. The tool description adds only that lookup is 'by slug,' which does not materially enhance the parameter semantics beyond the schema, so the baseline score of 3 applies.

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?

Clearly states the tool returns one bus category by slug, which distinguishes it from list_bus_categories ('one' vs. list). The phrase 'in full' hints at comprehensive detail, though it doesn't explicitly name get_buying_context as the sibling it contrasts with, so differentiation is partial but adequate.

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 when a specific category slug is known, and the promise of 'related categories worth considering instead' suggests a comparison or alternative-seeking use case. However, it does not explicitly state when to prefer list_bus_categories or get_buying_context, leaving usage guidance mostly implicit.

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