usgs_water_data

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

The readOnlyHint annotation already declares the tool is read-only, and the description adds useful context like station count and parameter codes with units. However, it overstates query capabilities (county/HUC) and does not disclose response format or any rate limits, which matters since there is no output schema. It does not contradict the annotation, but the false capability claim reduces transparency.

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 sentences, front-loaded with the primary action, and compact. It includes valuable quick-reference data (station count, parameter codes/units). The third sentence about query methods is efficient but contains an inaccuracy, preventing a perfect score.

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?

The tool has 6 optional parameters, a read-only annotation, and no output schema. The description covers data type, station scale, parameter codes, and query entry points, but it omits any indication of what the response looks like (since no output schema exists) and incorrectly lists county/HUC as query options. Given the richness of the schema and the sibling tools, a clearer tie to usgs_daily_water_data would improve completeness.

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 100%, so the baseline is 3. The description repeats parameter code meanings already present in the schema (00060, 00065, 00010) and adds the 'query by county/HUC' claim, which does not map to any parameter. It provides no additional semantic value for parameters beyond what the schema already documents, and the unsupported query methods could mislead parameter usage.

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 retrieves real-time water data (streamflow, gage height, temperature) from USGS monitoring sites, with a specific verb and resource. It provides enough detail to distinguish it from siblings like usgs_water_sites or usgs_daily_water_data by emphasizing 'real-time', though it does not explicitly name alternatives. The claim about querying by county or HUC is misleading because those params are absent from the schema, slightly detracting from clarity.

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 some usage context—'real-time' data, query by site ID/state—but it does not explain when to use this tool versus the closely related usgs_daily_water_data or usgs_water_sites. More problematically, it claims county and HUC queries are supported, but the schema only provides sites and state_cd, which is actively misleading guidance for an agent deciding how to query.

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