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

Annotations already establish readOnly, openWorld, and non-destructive behavior; the description adds a non-obvious behavioral guarantee ('Always returns a list, even for a single match') and scopes the search to the port registry. It does not cover result limits or empty-input behavior, but with annotations carrying the safety profile the added context is solid.

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 cover purpose, return fields, search modes, single-match list behavior, and alternative tool. Every sentence earns its place and the key purpose is front-loaded.

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 tool with nine optional parameters and no required fields, the description gives enough orientation to select search modes and know the return shape. It leaves minor ambiguity about whether multiple filters can be combined and what an empty search returns, but the output schema and 'always returns a list' guarantee cover most operational needs.

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 the baseline applies. The description does add helpful grouping of the nine parameters into search modes (name with optional fuzzy, UN/LOCODE, classification, country, geography), but it largely restates constraints already present in the schema such as radius requiring lat and lon.

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 opens with a specific verb and resource: 'Search the port registry and return matching ports' plus the exact fields returned. It also differentiates from the sibling get_port by stating that full detail on one known port belongs there.

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?

Provides explicit usage criteria: 'Use this to discover ports or resolve a name to a UN/LOCODE/uuid' and names the alternative get_port for known-port detail. This tells an agent exactly when to pick this tool over siblings.

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