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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the 'full, multi-region' scope and its role as a lookup for other tools' output, which is useful context, but discloses nothing about output shape, pagination, or rate behavior. A 3 is appropriate given the annotation coverage.

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 sentence that is front-loaded with the core resource and immediately follows with the cross-tool purpose. Zero wasted words.

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?

An output schema exists, so return values need no explanation, and the description adequately conveys what the tool yields (human-readable size names across regions). For a zero-parameter read-only lookup, this is essentially complete, with only marginal room for explicit usage sequencing.

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?

The tool takes zero parameters, so there is no parameter syntax for the description to clarify. Baseline 4 applies since there are no semantics to add beyond the empty 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?

States a specific resource (Depop's full multi-region size taxonomy) and its function (resolving opaque size codes to human-readable names). It distinguishes itself from depop_search and depop_shop by naming them explicitly, though it is framed as a noun phrase rather than a clear verb+resource.

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 implies the usage context clearly: call this to decode the otherwise-opaque sizes filter returned by depop_search and depop_shop. This routes the agent to the right sibling, but it does not state an explicit when-not or prerequisite (e.g., call this before filtering).

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