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

With no annotations, the description carries the full burden and does well: it discloses the underlying data source (live AIS vessel transponders) and the unit convention (hours). It stops short of stating refresh cadence/true real-time latency behind 'live' or behavior on unrecognized port codes.

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?

Three tight sentences with the capability front-loaded before usage and exclusions. Slight redundancy between 'anchored vessels waiting count' in sentence one and 'anchored container vessel queues' in sentence two costs a point.

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 one-parameter tool with no output schema, the description successfully sketches the return contents (waiting counts, average berth wait times in hours). What's missing is any freshness or reliability signal for data branded 'live'.

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 the single parameter's format (UN/LOCODE or major seaport name) is already fully documented. The description adds no parameter-level guidance beyond implying a port identifier is needed, which is the baseline-3 case.

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 (live seaport congestion metrics, anchored vessel counts, average berth wait times) and explicitly distinguishes itself from getContainerFreightRates and air cargo. An agent can identify the tool's output shape without opening the schema.

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 when-to-use triggers (monitoring seaport bottlenecks, anchored vessel queues, berth waiting hours, customs clearance delays) and a named exclusion routing to getContainerFreightRates plus air cargo. Both the positive and negative conditions are stated.

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