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

No annotations are provided, so the description must carry behavioral information. It states that the tool returns 'every published field', which discloses the completeness of the response. However, it does not mention error behavior (e.g., what happens if the slug is not found), authentication requirements, or any potential side effects. For a read-only fetch tool, this is a minimal but not exhaustive disclosure.

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?

The description is a single sentence that is concise, front-loaded with the action, and includes a meaningful qualifier ('with every published field'). It contains no fluff or redundant wording, making it highly efficient.

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 simple one-parameter fetch operation, the description is nearly complete. It covers what is fetched and the method, and the schema covers the parameter source. The absence of an output schema means the 'every published field' phrase serves as a return-value expectation. However, it could be slightly more complete by explicitly stating that the slug comes from search_products within the description itself, rather than relying on the schema.

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 input schema has 100% coverage: the required 'slug' parameter is described as 'The listing slug, as returned by search_products.' The main description does not add any further semantic detail about the parameter, but the schema description is already informative and sufficient given the simplicity of the parameter.

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 'Fetch one listing from the AI Product Index by slug, with every published field' uses a specific verb ('fetch'), names the resource ('listing', 'AI Product Index'), and clarifies the selection method ('by slug'). It clearly distinguishes from sibling tools like search_products by focusing on retrieving a single item rather than searching.

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 implicitly conveys the use case: obtain a single listing when you already have its slug. While it doesn't explicitly state 'use this instead of search_products when you have a slug' or list exclusions, the context is clear enough. The schema description for 'slug' explicitly says 'as returned by search_products', which reinforces the relationship to the sibling search tool.

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