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

No annotations are provided, so the description carries the full burden. It does disclose the 30-day lookback cap and the returned metrics (min, max, latest, 24h change, rise rate), and the leading 'PRO' hints at a paid/subscriber tier, but it never states access requirements, rate limits, cost, or error behavior for gated access.

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?

Two terse fragments — a tier flag and a single sentence — with the resource and returned metrics front-loaded. No filler, though the standalone 'PRO.' marker is slightly cryptic as an opener.

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 description compensates for the absent output schema by enumerating return values, which is the key gap filler. However, with no annotations and gated access implied, it should clarify what 'PRO' entails (subscription requirement, what happens with a free token), which an agent needs to call it successfully.

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 coverage is only 33% (only access_token is documented), so the description must compensate. It does add meaning to 'days' by capping history at 30 days and clarifies 'station' as the subject of the query, but it leaves the units/type of days (a number, floor vs. fractional) and station identifier format ambiguous.

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?

States a specific resource and operation: level/flow history for a single station, with the aggregate outputs enumerated. It implies differentiation from river_levels (current values) and flood_watch (alerts) via 'history' and 'trend', but never names the siblings explicitly.

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?

Usage is implied by 'history ... up to 30 days', which suggests retrieving a time series for one station rather than current readings. There is no explicit when-to-use vs. when-not guidance and no mention of the sibling tools flood_watch or river_levels as alternatives.

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