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

Annotations declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true. The description adds meaningful behavioral context beyond annotations: null fields for unpublished data, 'unknown' severity, the exact source denominator, payment failure returns 402, and the unchanged API envelope. This is rich, non-contradictory disclosure.

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 moderately dense but every sentence earns its place: purpose, data behavior, denominator detail, payment, and return envelope. Slightly longer than minimal but front-loaded and well-organized, with no fluff.

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 specifying the return envelope shape, null/unknown behavior, payment conditions, and a distinct alternative for advisories. It fully equips an agent to understand tool behavior and select correctly.

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 baseline is 3. The description repeats the USLAX denominator already present in the port parameter schema but adds no new parameter-specific guidance. It does not compensate beyond the schema's existing detail.

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 opens with a specific verb+resource: 'Get certified port-authority congestion measurements for a specific port.' It clearly distinguishes from sibling tools by naming shippingrates_congestion_news for disruption advisories, which resolves any ambiguity about scope.

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?

Explicitly states when not to use this tool ('For disruption advisories, use shippingrates_congestion_news instead') and provides usage context such as the current certified denominator (USLAX) and the payment requirement. This gives the agent clear decision criteria.

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