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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered. The description adds real value beyond that: the ordering (most delayed first), the default threshold of 24 hours, and the definitional anchor that the baseline is the first ETA observed rather than a previous query. It does not mention pagination or what fields a shipment returns.

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?

One dense sentence, front-loaded with the resource and scope, followed by the threshold and ordering. No filler or repetition.

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 read-only, three-parameter, non-destructive query with rich annotations, the description covers the essentials of what is returned conceptually. The only gap is that no output schema exists and the description doesn't hint at the shape of a shipment record, though the sibling get_shipment presumably covers detail.

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 all three parameters are already documented in the schema. The description restates min_delay_hours and its default, which is mildly reinforcing but adds no new semantics; limit and company are untouched. Baseline 3 is appropriate.

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 precisely defines the resource (active shipments) and the filter criterion (ETA slipped vs the first ETA BerthTime saw by at least min_delay_hours), which is far more specific than a generic list. It implicitly separates itself from list_shipments and arriving_soon by the 'slipped ETA' condition, but never names an alternative explicitly.

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 implied by the definition of the dataset, so an agent can infer when this applies. There is no explicit guidance about when to prefer arriving_soon or list_shipments instead, and no exclusions or prerequisites stated.

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