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

Annotations already establish read-only, idempotent, open-world behavior. The description adds meaningful context beyond that: country membership remains unknown without verified lists, release records identify editions but do not enable historical lookup, and pagination must be followed via nextCursor. That is useful behavioral scope for a reference-list tool.

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 content is front-loaded and compact, with no filler. However, the first sentence is a dense list of disparate topics, and the relation between clauses is not always immediately clear. It earns its place but could be more scannable.

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 an output schema present, the description needn't explain return values. It covers the topic families, pagination expectation, and important exclusions about country membership and historical lookup. It is complete enough for correct invocation, though a clearer when-to-use statement would strengthen it.

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%, and the schema already documents limit clamping, cursor opacity, and topic enumeration. The description only restates that several topic families exist and says to follow nextCursor, adding little semantic detail beyond the schema. Baseline 3 is appropriate.

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 names a specific retrieval action and enumerates the five reference topics (identifiers, SPIs, chapters, units, releases), matching the topic enum. It also implicitly distinguishes itself from sibling tariff-lookup tools by noting that release records do not enable historical tariff lookup. It is clear, though somewhat terse about being a reference-table tool.

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?

It provides useful exclusions: program names are decoded separately from country membership, and release metadata does not support historical tariff lookup. This helps an agent avoid misusing the tool. It does not explicitly name sibling alternatives or state the primary 'use this before/after' workflow, keeping it below a 5.

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