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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so safety is covered. The description adds useful detail about the breadth of the returned record, but it does not disclose operational details such as pagination, data freshness, or how 'declared' compatibility should be trusted. That is acceptable but not exceptional.

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?

One dense but front-loaded sentence; the opening phrase establishes the operation before the comma-separated list of content. Every listed item contributes information, though the sentence is slightly long.

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?

For a one-parameter read operation with a full output schema and read-only annotations, the description covers the important selection signal: it returns all catalog details for a single add-on. Nothing an agent needs to invoke it correctly is missing.

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 slug parameter already has a descriptive definition with a URL example. The description adds no additional meaning to the parameter, so it meets the baseline but does not exceed it.

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 resource ('a single add-on') and a clear scope ('everything the catalog holds'), then itemizes the data returned. This makes it easy to distinguish from siblings like price_history, list_deals, and list_addons_for_aircraft, which serve narrower or multi-item purposes.

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 clearly implies this is the tool to use when a complete record for one add-on is needed, and the field list signals that narrower tools like price_history or search_addons are for different jobs. However, it never explicitly names alternatives or says when not to use it.

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