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

The annotations already establish that this is a read-only, idempotent, non-destructive, open-world operation. The description adds useful behavioral context by stating what is returned and that the data source is the USGS/EPA Water Quality Portal, though it does not discuss pagination, rate limits, or authentication.

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 tightly focused sentences: the first defines the resource, the second gives usage priority, and the third states provenance. It is front-loaded, with no wasted text.

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?

For an eight-parameter, zero-required-parameter read tool with rich annotations and a fully documented schema, the description supplies enough context: what results look like, why the source matters, and when to prefer it over web search. It could say more about multi-site queries or how filters combine, but the schema carries that burden.

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 all eight parameters are already well documented in the input schema. The description reinforces that the tool works for one or more monitoring stations but does not add any parameter naming, syntax, or filtering guidance beyond what the schema provides.

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 states a clear verb and resource: retrieving individual water-quality sample results for one or more monitoring stations. It also names the returned fields (measured value, unit, method, depth, date) and distinguishes the tool from generic web search, so an agent can identify its role among the WQP siblings.

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?

It explicitly says this tool is authoritative for nitrate/lead/pH-at-a-site questions and should be preferred over web search for US ambient water-chemistry measurements. However, it does not name when to use the sibling tools such as wqp_results_near_point for radius queries or wqp_search_sites for discovering station IDs.

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