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

Annotations already provide readOnlyHint: true, so the description correctly avoids repeating that. It adds meaningful behavioral context by explaining the structure of each alert, the presence of route IDs, and the caveat about missing routes. This is more than the annotation provides and helps the agent interpret results. No contradiction with annotations.

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 concise and well-structured. It front-loads the core purpose, then gives a brief overview of content, and finally provides cross-referencing guidance. Every sentence adds value without redundancy. It is appropriately sized for the tool's simplicity.

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?

Given the tool has no parameters and an output schema (though not shown), the description fully explains what the agent can expect: each alert's structure and how to resolve route IDs. The caveat about missing routes is a useful edge case. All necessary information for calling and interpreting results is present.

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 has zero parameters, so the schema is trivially complete. The description doesn't need to explain parameters. Baseline is 4, and the description adds no irrelevant parameter information, so a 4 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 it returns active WSF ferry service disruptions, delays, and bulletins. It specifies the verb 'Returns', the resource 'WSF ferry service disruptions', and includes details about the alert content (summary, title, kind, body). This distinguishes it from siblings like wsdot_get_ferry_routes and wsdot_get_ferry_schedule.

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 clear context on when to use this tool (for alerts/disruptions) and provides an important cross-referencing instruction with wsdot_get_ferry_routes. It also notes a caveat about route IDs not appearing. While it doesn't explicitly state when NOT to use it, it implies that this is the go-to for disruptions. The guidance is sufficient for an agent to select it appropriately.

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