bart_stations

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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds the specific return fields, which is useful, but does not disclose any additional behavioral details such as data volume, pagination, or update frequency.

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, with the action and scope in the first sentence and the return values in the second. No wasted words.

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 zero-parameter list endpoint, the description is adequately complete: it states the resource, scope, and return fields. It does not mention potential limitations like pagination, but given the tool's simplicity and readOnlyHint annotation, this is sufficient.

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 accepts no parameters, so the description need not document any. Schema coverage is effectively 100% with an empty properties object, and the baseline for zero-parameter tools is 4.

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 uses a specific verb 'List' and identifies the resource 'BART (San Francisco Bay Area) stations,' and clarifies the return fields, distinguishing it from sibling tools like bart_departures and bart_advisories.

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 when to use the tool (when a list of BART stations is needed) but does not explicitly mention alternatives or exclusions. It provides clear context about the resource, but no guidance on when not to use it or when to prefer another tool, such as bart_departures.

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