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 a modest amount over the annotations by noting the per-marketplace listed counts in the response, but says nothing about failure behavior when a slug is invalid or how partial results are returned.

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 efficient sentence with the batch scope front-loaded and no filler. It earns its place, though the 'per-marketplace listed counts' clause is the only content carried beyond the name.

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 not be explained, and the annotations cover safety. For a one-parameter batch lookup this is nearly complete; only the alternative-routing guidance is absent.

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% — the slugs parameter already documents the comma-separated format, the 50-item cap, and that it is required. The description adds no parameter-level detail beyond the schema, so the baseline of 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?

States a specific verb ('look up'), resource ('OpenSea collections'), and scope ('several at once'), plus a return-value hint ('per-marketplace listed counts'). The plural/batch nature implicitly distinguishes it from the singular opensea_collection sibling, though the sibling is never named.

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?

'At once' implies a batch use case, but there is no explicit guidance on when to choose this over opensea_collection (single detail) or opensea_search_collections (discovery). Usage must be inferred from the plural framing.

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