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

With no annotations supplied, the description carries the full burden and does substantial work: it discloses that results vary by proxy (Buyee returns a real affiliate URL, others return public pages flagged placeholder:true) and that the alcohol category is suppressed. It also pre-empts a safety concern by stating it never executes a purchase. Gaps remain: it does not say what is actually returned when alcohol is suppressed (error, null, or omitted field), nor whether any auth or rate limits apply.

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?

Four short sentences, front-loaded with the core behavior, and each sentence adds distinct information about output variation or safety. The telegraphic phrasing 'when not alcohol' is grammatically awkward and momentarily ambiguous, which costs a little comprehension, but nothing is padded or redundant.

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 four-parameter tool with no annotations and no output schema, the definition covers the important behavioral branch points (Buyee vs. other proxies, alcohol suppression) and the read-only nature implied by 'never executes a purchase'. It is still incomplete on return shape (beyond the placeholder flag), the suppressed-alcohol outcome, and the lang parameter's effect, leaving real questions an agent would want answered before calling.

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 only 25% (only item_url is annotated), so the description is expected to compensate. It does add meaning for proxy and category by explaining that proxy determines affiliate-versus-placeholder behavior and that alcohol is suppressed. The lang parameter and the interaction between category and the suppression rule are left unexplained, so compensation is partial.

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 states a concrete resource and effect: an outbound referral/affiliate link produced for a given proxy, with Buyee behaving differently from other proxies. It is recognizably the link-generation tool rather than a cost, shippability, or listing tool. It stops short of a clean verb-plus-resource sentence ('Outbound link for a proxy' is a fragment) and never names a sibling, so it is clear but not sharply differentiated.

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?

Usage is only implied: an agent can infer this is the tool to call when it needs a buy/affiliate URL for an item through a proxy. There is no explicit 'use this when' statement, no when-not condition, and no comparison to compare_proxies or list_proxies. The per-proxy conditional behavior is useful but describes output, not selection.

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