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

Annotations already declare readOnlyHint=true, and the description adds valuable context: the score range (0-100), the probabilistic daily delay distribution methodology, and 'Updates: daily.' It also discloses output components (trend, confidence, top_drivers). No contradictions exist.

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 description is three sentences: a detailed but compact return-spec sentence, a use-case sentence, and an update-frequency sentence. It is front-loaded with the core purpose and every sentence provides distinct value, though the first sentence is slightly dense.

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 compensates by naming the return components (score, trend, confidence, top_drivers) and update cadence. The optional history behavior is fully documented in the schema. Overall, it gives sufficient context for a straightforward read-only metric tool.

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% for the single optional 'days' parameter, including range, semantics, and tier requirement. The description does not repeat parameter details, but per the rubric, the baseline is 3 when the schema carries the full burden; no additional semantic value is added beyond the schema.

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 states a specific verb ('Returns') and resource ('0-100 port-congestion lead-time variance score'), explains the underlying data sources (AIS arrivals, dwell times, crane productivity), and lists output components (trend, confidence, top_drivers). This clearly distinguishes the tool from any sibling by its unique metric and domain.

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?

The description gives explicit call scenarios: 'Call when the user asks about port congestion, shipping delays, container lead times, or inventory buffer adequacy, or when timing safety-stock changes, expedited-freight bookings, or purchase-order pull-forwards.' It lacks explicit when-not-to-use or named alternatives, but the clear positive usage context is strong.

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