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

The annotations already declare readOnlyHint=true, and the description aligns by describing a read-only search that returns data. The description adds modest value by specifying return fields and suggesting further actions, but it does not delve into potential pagination, rate limits, or other behavioral nuances. Given that annotations cover the safety profile, this is adequate but not exceptional.

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 three concise sentences with no filler. It front-loads the primary purpose, immediately states return contents, and then provides a practical tip for using the output. Every sentence earns its place, and the structure is ideal for quick agent comprehension.

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 geographic search tool with six parameters fully documented in the schema and an output schema present, the description covers the essential context: what it finds, what it returns, and how to use the results. It does not mention potential pagination or result limits, but given the output schema and the relative simplicity of the tool, this is a minor omission. The description is complete enough for correct invocation.

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 schema describes all six parameters thoroughly, achieving 100% coverage, so the description adds little to parameter meaning. It does mention 'filtered by name or number' which maps to the query parameter, and 'near a location' implies lat/lon, but these are already explicit in the schema. The description adds no new semantic depth beyond the schema, so a baseline score of 3 is appropriate.

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 a specific verb ('Find'), resource ('transit routes'), and context ('near a location') with an optional filter. It also lists the returned fields (IDs, short names, descriptions), making the purpose distinct. However, it does not explicitly differentiate from sibling tools like onebusaway_search_routes, which could also locate routes, so it loses a point for not addressing sibling ambiguity.

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 gives no guidance on when to use this tool versus alternatives such as onebusaway_search_routes or onebusaway_find_stops. It only mentions downstream usage of routeId values, which is helpful for post-call actions but does not help the agent decide between spatially searching routes and other search or retrieval tools. No exclusions or comparative criteria are provided.

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