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

Annotations already cover the safe read-only/idempotent profile, and the description adds real behavioral context beyond them: the 45-day discharge window, urgency ordering, the demurrage/detention clock semantics with days-left and active clock, the meaning of terms_unknown, and the instruction to use the provided shipment_url rather than fabricate one.

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?

Front-loads the resource and urgency ordering, then packs output semantics and the URL-safety rule into tight sentences. With no output schema, none of the return-value detail is redundant, and nothing is padding.

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?

A parameterless list tool with no output schema needs the description to carry the return-shape burden, and it does: clock fields, terms_unknown, and the shipment_url linking rule are all present. An agent can call and render this correctly from the text alone.

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?

Zero parameters, so per the baseline this is a 4. 'Takes no arguments' simply confirms what the empty schema already shows, adding no new parameter meaning.

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 resource and scope: ocean shipments whose demurrage/detention free time is running out or already over, sorted most urgent first. This is unambiguous and clearly separable from generic siblings like search_shipments or list_alerts.

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?

Gives two concrete trigger questions ('what will cost us demurrage this week', 'which containers should we pick up first') plus a hard scope constraint (discharged in the last 45 days only). It stops short of naming an explicit alternative or when-not condition, but the intended use is obvious.

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