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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely useful behavior beyond that by disclosing the not-found error for a nonexistent id, which the annotations do not convey.

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?

Front-loaded with the core action and efficiently sized at three sentences. The em-dash clarification of the source shelf is slightly resolving, but it materially aids disambiguation and earns its place.

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. The description covers the id source and the key error case, making it largely complete for a simple two-parameter read tool, with the minor gap being the undocumented limit parameter.

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 0%, so the description must carry the parameter burden. It does well for id, stating it is the listing's numeric id and naming where to source it (search, sold-listings, or collection result id field), but says nothing about the optional limit parameter, leaving it undocumented in both places.

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: it lists Grailed's recommended 'similar' listings for a given listing. The clause 'the same related-items shelf shown on grailed.com's own listing-detail page' anchors exactly what set is returned, distinguishing it from grailed_listing and grailed_search without needing 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?

Usage is implied by the described data source (the site's own recommendation shelf), which tells the agent roughly when this is relevant. However, no alternative tool is named and there is no explicit when/when-not guidance relative to siblings like grailed_listing or grailed_collection.

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