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

The annotations already establish this is a safe read of a closed, non-open-world source, so the description's job is to add context. It does add the unit and datum (metres MLLW) and states that the next high and low are included in the response, but it says nothing about data freshness, update cadence, or what happens when a station is invalid or offline.

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?

One compact sentence with no filler, and the core payload (latest observed water level) is front-loaded before the supplementary tide info. The trailing 'with the next high and low' is slightly compressed but still parses cleanly.

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 a one-parameter read-only tool with full schema coverage and no output schema, the description covers what is returned (level in metres MLLW, next high and low) and the domain of the input. Only freshness and failure behavior are left unstated, which is a minor gap at this complexity.

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?

There is a single required parameter and schema coverage is 100%; the schema already explains that 'station' is a NOAA CO-OPS id with a concrete example. The description reinforces the domain ('NOAA tide station') but adds no syntax, format, or validation meaning beyond the schema, so 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 uses a specific verb and resource: it returns the latest observed water level at a NOAA tide station, plus the next high and low. That is enough to distinguish it from tide-prediction or nearby-station tools without opening a schema, though it never names those 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?

'Latest observed' implies the current-reading use case as opposed to forecasts or historical series, and the presence of sensors_tide_predictions and sensors_water_history in the sibling list makes that distinction relevant. However, the description never says when to prefer this over those tools or what preconditions apply, so the guidance remains implicit.

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