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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered; the description instead contributes the substantive behavioral detail an agent cannot get elsewhere — that the response includes a status verdict, a comparison against a normal baseline, weeks-below-normal duration, 8 weekly totals with share-of-normal, 14 daily counts, the underlying rule, and a gaduin.com link. It does not disclose data freshness, units/scale of 'share of normal', or behavior on an unknown slug, which keeps it from a 5.

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?

A single front-loaded sentence moves from purpose to an inventory of returned fields with no filler. It is long and comma-chained rather than broken into digestible clauses, but every listed item is load-bearing given the absence of an output schema.

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 must carry return-value disclosure, and it does so thoroughly enough for an agent to decide whether the tool answers a given question. Remaining gaps are modest: baseline definition/units, data currency, and error behavior for an invalid slug.

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?

One parameter at 100% schema coverage: the schema already says slug comes from list_chokepoints and gives examples (suez, panama). The description adds no additional meaning about the slug format or resolution behavior, so the baseline 3 applies.

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 resource and scope: ship traffic through ONE maritime chokepoint, and enumerates exactly what comes back (status, daily mean vs normal, weekly totals, rule, link). It is clearly distinguishable from list_chokepoints, though it does not name that sibling as the required first step — the schema does that instead.

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 only implied: the singular chokepoint scope and the slug parameter signal 'call list_chokepoints first, then this tool for one slug', but the description never states when to use this versus alternatives or any prerequisites/exclusions. Adequate but inferential.

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