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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds the auth requirement ('Needs an access token'), which is genuine context beyond the structured fields, but it says nothing about prerequisites like the listing needing to be free/approved, nor whether the returned code differs per product.

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?

Three short sentences with zero filler; the artifact description leads and the operational notes follow. Minor cost: the sentence fragments make the object of the tool slightly ambiguous at the front.

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 single-parameter read tool with no output schema, the description covers what the artifact is, the two acceptable forms (text link or badge image), where it goes, and the auth requirement. It does not say whether both variants are returned or how they are selected, which is the remaining gap.

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?

With one parameter at 100% schema coverage, the schema already explains productId and even names the sibling tools that produce it. The description adds no parameter-level meaning, so the baseline 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?

The description names a specific artifact — 'the HTML link the product's homepage must carry for a free listing' — so the resource is identifiable, but it is a noun phrase with no verb; the agent must infer that the tool retrieves/returns that snippet rather than, say, validating it. It also does not distinguish itself from the sibling verify_backlink, which deals with the same backlink concept.

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?

'Add one to the site footer' implies the lifecycle stage (after listing, before verification), and 'Needs an access token' is a real precondition. But there is no explicit when-to-use statement and no routing to alternatives such as verify_backlink or update_listing, leaving the sequence to inference.

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