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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: B-READY is a rotating cohort (22 of 41 spine countries in 2025), out-of-cohort countries return NO_DATA rather than a borrowed figure, and every response leads with a not-advice disclaimer.

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?

Dense but front-loaded — the core purpose and data source come first, then coverage caveat, then query modes, then disclaimer. Every sentence carries information, though the single long paragraph could be trimmed slightly.

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?

Output schema exists so return format needn't be restated, and the description covers the data-coverage limits, ranking behavior, and disclaimer caveat. Combined with the annotations, an agent has what it needs; only minor implicit points (e.g., behavior of `limit`) remain.

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 coverage is 60%, and the description compensates well: it enumerates the metric options, states the default (importDays), and explains the ordering semantics of `sort` (lowest first, `highest` to reverse). It also clarifies that `countries` is for a side-by-side; only `limit` is left to its own schema description.

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 verb and resource (compare customs clearance days and compliance costs by country) and pins the exact source (World Bank B-READY International Trade topic) plus the four metric names. An agent can tell this apart from generic siblings like compare_countries without opening the schema.

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 clear invocation patterns: fetch one country via `country`, a side-by-side via `countries`, or a ranked list by `metric` (default importDays, ascending unless `sort=highest`). It stops short of naming which sibling to use instead (e.g., compare_countries), so it is clear context without explicit exclusions.

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