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

Beyond the read-only and idempotency annotations, the description adds a strict requirement to answer only from retrieved results and warns against supplementing them with remembered transit details. The unofficial, non-affiliation disclaimer also supplies useful provenance context, though source freshness and unknown-topic behavior remain unspecified.

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 compact and front-loads the resource, scope, and usable topic values. The grounding constraint and affiliation disclaimer each add distinct, relevant information without unnecessary wording.

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?

For a simple one-parameter retrieval tool with an output schema and safety annotations, this provides nearly everything needed to select and invoke it. Explicit sibling differentiation and clarification of topic discovery or invalid-value handling would make it more complete.

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?

With 0% schema description coverage and no enum, listing the exact topic tokens—new_rider, visitor, payment, fares, accessibility, safety, and maps—substantially improves invocability. It could be clearer about whether this list is exhaustive and what happens when another value is supplied.

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 clearly states that the tool returns the full text of a primary rider guide and enumerates its supported subjects. It does not explicitly distinguish the tool from overlapping siblings such as get_fare, how_to_pay, or search_transit_info.

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 topic list provides clear context for when a guide lookup is appropriate, and the grounding rule explains how its results should be used. However, there is no explicit routing to sibling tools for fare calculations, payment instructions, or broader transit searches.

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