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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, covering the safety and idempotency profile. The description adds valuable context: the data source (environment.data.gov.uk/flood-monitoring), the UK Open Government Licence v3.0, and that no authentication is required. It does not contradict annotations.

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 purpose and filters, then return details, then follow-up guidance and data attribution. Every sentence contributes useful information without redundancy or fluff.

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 that an output schema is present, the description doesn't need to detail return fields extensively, but it still mentions key returned elements and how to use station_id. It covers data source, license, auth, and follow-up tool. It does not mention pagination or default limits, but those are covered by the schema's limit parameter with default. Overall, it is complete for an agent to call correctly.

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 has 100% description coverage, with each parameter already documented (town, limit, search, parameter, river_name, catchment_name). The description itself does not add parameter-specific details beyond what the schema provides, so it adds no extra value here. The baseline of 3 applies.

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 action (search), the resource (stations in the UK EA monitoring network), and enumerates the filterable attributes (town, river, catchment, parameter, freetext). It also specifies what is returned and how to follow up with the readings tool, making its purpose unambiguous and distinct from the sibling readings tool.

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 provides context for when to use this tool (searching for stations) and points to the readings tool for getting latest values, but it does not explicitly state when not to use it or mention alternatives like ea-hydrology.stations.search. The guidance is implicit rather than explicit.

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