oba_routes

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

The readOnlyHint annotation already indicates a safe read operation. The description adds that it returns route names, types, and descriptions, which is useful output context. However, it doesn't disclose potential edge cases (e.g., invalid agency_id behavior or pagination), though the bar is lower given the annotation.

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 two concise sentences, front-loading the main purpose and then adding the default agency and return contents. Every sentence delivers useful information without redundancy or verbosity.

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 list tool with one optional parameter, the description covers the essential elements: what it does, the default agency, and the return fields. Since there is no output schema, this return information is critical and is provided. A 5 would require more detail about pagination or error handling, but those aren't critical for this tool's basic use.

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 input schema already provides a full description for the single parameter (agency_id) with the default value and King County Metro mapping. The description adds 'Seattle' as clarification but essentially duplicates the schema. With 100% schema coverage, the baseline is 3, and the description doesn't significantly elevate it.

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 the tool's function ('List transit routes') with a specific geographic scope ('Puget Sound agency'), and distinguishes it from sibling tools by noting the default agency (King County Metro Seattle). It also mentions the output contents (route names, types, descriptions), making the purpose unmistakable.

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 provides clear context: use this tool to list routes for Puget Sound transit agencies, with King County Metro as the default. It doesn't explicitly mention alternatives or when not to use it, but the regional qualifier effectively differentiates it from other transit route tools like la_metro_routes or mbta_routes.

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