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

Annotations already cover readOnly, idempotent, openWorld and non-destructive behavior, so the bar is lower. The description still adds real value: it discloses that timestamps, source status and explicit nulls appear when data is unavailable, and that source/freshness metadata is returned. It does not discuss rate limits or spot-resolution failure behavior, keeping it short of a 5.

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?

Front-loaded with the core purpose and then units/behavioral caveats. Mostly earns its place, though the trailing sentence about water temperature, visibility and current-sign convention reads like a generic marine-data disclaimer and marginally dilutes focus.

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 no output schema, the description appropriately describes the payload shape (timestamps, source status, nulls, source/freshness metadata) and gives full unit/direction conventions. It is close to complete for a read-only forecast tool, missing only the hours-range semantics.

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 0%, so the description must carry param meaning. 'Verified spot' gives useful semantics for the spot param, and 'over the next hours' loosely ties to the hours param, but the default (24), min/max (1-168), and the spot string pattern are never explained, leaving half the nested parameters to guesswork.

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 verb+resource: wave height, period and swell for a verified spot over the next hours. This distinguishes it reasonably well from get_wave_models and get_chop, though it never names those siblings explicitly, so the differentiation is implied rather than stated.

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 phrase 'for a verified spot over the next hours' implies usage (spot-based near-term forecast), but there is no explicit when-to-use, when-not, or alternative naming among the many forecast siblings (get_wave_models, get_chop, get_surf_forecast, get_forecast). Usage is left to inference.

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