usgs_water_sites

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the description is not burdened with that. However, the description mentions 'hydrologic unit' as a filter, but the input schema has no parameter for it, which is misleading. It also does not disclose behavior like pagination, default results when no params are given, or the nature of the output. This mismatch and omission detract from 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 two sentences with no unnecessary fluff. It front-loads the search purpose and then lists site types. However, the site type list is redundant with the schema, so a more streamlined description might have omitted it. Still, it is concise and readable.

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?

With no output schema, the description should explain what the tool returns (e.g., a list of site records with identifiers and coordinates) and clarify that all parameters are optional. It does not mention default behavior when no filters are given, nor does it clarify the missing hydrologic unit parameter. For a search tool with three optional params, this is incomplete.

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 input schema covers all three parameters with descriptions, including the site type enum. The description merely repeats the schema's site type mapping and adds a misleading mention of hydrologic unit. Since schema coverage is 100%, the description adds no new meaning and even introduces confusion, so it falls below the baseline of 3.

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 searches for USGS water monitoring sites with filters by state, county, or site type. It lists specific site type codes, which helps identify the resource. However, it does not explicitly differentiate from sibling tools like usgs_water_data or usgs_daily_water_data, which likely retrieve data for these sites rather than metadata.

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?

There is no guidance on when to use this tool versus alternatives. The description does not mention that this is for site metadata lookup, nor does it state when not to use it or what other tools might be more appropriate. This leaves the agent to infer usage based solely on the name and description.

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