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

Annotations already cover readOnly, idempotent, openWorld, and non-destructive, so the bar is lower. The description adds genuinely useful context beyond them: the pay-per-call x402 pricing/allowance model and the caveat '(whichever it measures)' signalling that not all sensors exist at every station and fields may be absent.

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 sentences, output scope front-loaded, and the pricing sentence earns its place by warning of a metered cost. Zero filler.

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 an output schema present, return values need no explanation, and annotations carry the safety profile. The one shortfall is the absence of any routing against the four sibling tide tools, which an agent would still need to resolve elsewhere.

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%, with both 'units' (metric|english) and 'station' (NOAA CO-OPS id) documented in the schema itself. The description adds no syntax, format, or default detail beyond that, so the baseline 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?

Names a specific resource set (water temp, air temp, wind, air pressure) and the scope (latest, reported at a station), which is clearly distinct from a sibling like water-level or predictions. It does not, however, explicitly contrast itself with those siblings, so an agent still has to infer the split.

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 never says when to pick conditions over predictions, station, stations-near, or water-level. The only conditional content is pricing ('free within the daily allowance, then $0.002 USDC'), which is cost guidance rather than usage guidance.

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