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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior. The description adds genuinely new traits: a hard cap of 20 results, ordering by harbor size (larger first), harbor size being World Port Index-only, and no API key requirement. Return-field disclosure is also present.

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?

The find verb and search keys are front-loaded, and the result cap plus ordering are stated cleanly in their own short sentences. The middle list of return fields is dense but each item is load-bearing, so little is wasted.

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 carries the return-shape burden and does enumerate the fields (id, name, country, UN/LOCODE, position, harbor size, radius). Combined with the result cap and ordering, an agent has enough to call and interpret it, though auth/pagination specifics are unaddressed.

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 75%, so the schema handles much of the parameter documentation. The description still adds value by clarifying that query permits partial matches ('or part of it') and by giving concrete UN/LOCODE and country-code examples that the schema lacks.

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 (Find) and resource (ports) and enumerates the three search keys (name/partial name, UN/LOCODE, country code). It also names the backing references (World Port Index and UN/LOCODE ports), which no sibling tool shares, so an agent can distinguish it immediately.

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?

It clearly conveys the search modes and hints that the returned id feeds port_calls, which implies usage context. However, it never explicitly states when to prefer find_port over siblings like port_calls or vessels_in_area, so routing is left partly to inference.

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