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

Annotations cover readOnlyHint and openWorldHint, so the safety profile is already provided. The description adds useful context about what the response contains (grouped price levels with quantities), but says nothing about order-book freshness, pagination, or result size limits—relevant for a live market-data endpoint.

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?

Two sentences, front-loaded with the scope/return shape followed by sibling routing. No filler.

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 values needn't be explained, and routing is fully covered. Slight gap only on freshness/pagination behavior for a live order-book tool, but that is minor given the schema and annotations.

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?

Only one parameter with 100% schema coverage, and the schema already documents slug with an example. The description mentions 'by slug' but adds no format or disambiguation 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?

Specific verb+resource ('Fetch an OpenSea collection's full order-book depth data by slug') with the exact output content enumerated (active listings and offers grouped into price levels with quantities). Clearly distinguished from the two named siblings.

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?

Explicitly names both alternatives and the condition selecting each: opensea_item_depth for one item's book, opensea_collection_offers for collection offers. Routing is unambiguous.

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