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

Annotations already declare read-only, idempotent, open-world, and non-destructive behavior, so the bar is lower. The description adds valuable context beyond annotations: units (ft, kt, s, F, mi), direction convention (FROM), source/freshness metadata, and the caveat about empty reports. It does not cover rate limits, authentication, or pagination, but is helpful for a read-only dataset tool.

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 short and front-loaded with the dataset identity and variables. The units line and caveat are terse and necessary, though the 'with source and availability' phrase is slightly vague. It is efficient and wastes little space.

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 a nested filter parameter with zero schema descriptions and no output schema, the description omits any parameter guidance and does not clarify spatial or temporal coverage. It does provide units, source metadata, and an empty-report caveat, which helps for interpretation, but leaves significant gaps for calling the tool with filters.

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?

Schema description coverage is 0% and the description does not mention the single query parameter or its nested bbox and category fields at all. The description provides no meaning beyond the empty schema, leaving the agent unable to know how to filter or what the parameter does. This is a critical gap for correct invocation.

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 names the specific USGS dataset and the three variables (flow, salinity, water temperature) plus source and availability. It is clear about the resource but does not explicitly distinguish this tool from siblings like get_water_temperature or get_currents, and it lacks a direct verb like 'retrieve'. A strong but not perfect statement of purpose.

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 usage by stating the data source and including a caveat that empty reports do not establish safe conditions. However, it gives no explicit when-to-use guidance, no exclusions, and no routing to alternative tools for similar data. The guidance is implied rather than stated.

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