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

With no annotations, the description carries the full burden. It discloses the returned fields (name, slug, coordinates, timezone, country), which implies a read-only lookup, but says nothing about default result count, ordering, behavior on zero matches, or that partial matching is the search mode.

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 short sentences, front-loaded with the action and followed by the return shape. Nothing is padded, though the return-field list is a slight redundancy with an implicit result contract.

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 simple three-parameter lookup with full schema coverage and no output schema, stating the returned fields makes it callable without ambiguity. The only meaningful gap is not tying the returned slug to the downstream get_* tools.

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 100%, so limits, partial-name matching, and country slug format are already documented in the schema. The description only restates the high-level search dimensions (name or country) and adds no format or combination guidance beyond that.

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 names a specific verb and resource ("Search for tide stations") and clarifies that the resource is referred to as a port, which resolves the name/description mismatch. It doesn't explicitly contrast with any sibling, but the search semantics versus the get_* siblings is reasonably self-evident.

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 only implied: it is the lookup step before calling get_tides/get_conditions. The description never says when to use this instead of list_countries or that the returned slug feeds the get_* tools, so the agent must infer the workflow.

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