usgs_water_data

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, covering the safety profile. The description adds useful behavioral context by listing station count (13,000+) and defining parameter codes with units, which are not in the annotations. It does not contradict annotations, and it enriches the agent's understanding of scope.

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 with no redundancy. It front-loads the core purpose, then provides concrete details (parameter codes, units, query options) in a compact, scannable format. Every sentence earns its place, and there is no padding.

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, no output schema, and safety covered by annotations. The description explains data types and units but omits response format or any guidance on required filters (all params optional, so querying all 13,000+ stations could be possible but is not addressed). The misleading county/HUC reference also detracts from completeness, leaving the agent with some ambiguity about how to structure a valid query.

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% (each parameter has its own description), so the baseline is 3. The description repeats parameter code definitions already in the schema, but also claims query support for 'county, or hydrologic unit code (HUC)' while the schema only exposes sites and state_cd — no county or HUC parameters exist. This introduces a misleading dimension and fails to compensate for the schema's coverage, so it scores below baseline.

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 verb (Get) and resource (real-time water data from USGS monitoring sites), and lists the specific data types (streamflow, gage height, temperature). It distinguishes itself from siblings like usgs_daily_water_data and usgs_water_statistics by specifying 'real-time', making its purpose unambiguous.

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 for real-time water data and mentions query dimensions (site, state, county, HUC), but it does not explicitly exclude alternatives or state when to prefer this tool over usgs_daily_water_data or usgs_water_statistics. The distinction is clear from context but not spelled out, so it earns a 4 rather than a 5.

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