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

Annotations already cover safety (readOnlyHint, idempotentHint, destructiveHint=false), and the description adds genuinely new context: the free-tier allowance and the $0.001 USDC per-call x402 pricing, which materially affects whether an agent should call it. It does not describe result limits or what happens on zero matches, but the output schema covers the return shape.

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, front-loaded with purpose then the cost model, with no filler. Every clause carries information an agent needs.

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 not be explained, and the description covers purpose, filters, and the cost model. It is slightly thin on edge cases (no-match behavior, result caps) for a search tool, but nothing essential is missing.

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%, so both parameters are already documented ('station name contains' and '2-letter state'). The description only restates that they are combinable filters; that is baseline-correct but adds no new syntax or matching semantics.

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 (search) and resource (NOAA tide stations) plus the filter dimensions (name and/or state). It is not identical to its siblings tides__station and tides__stations-near, but it never explicitly says how it differs from them, so an agent must infer the distinction.

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?

Searching by name and/or state is implied, and the cost caveat hints that this is a lookup call. However, there is no explicit when-to-use guidance versus tides__stations-near (proximity) or tides__station (single known station), leaving selection to inference.

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