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

Beyond the readOnly/idempotent annotations, the description reveals that product URLs are read live at load and that store counts appear only when the retailer record carries one. It also discloses the gate_transaction dependency, giving the agent a realistic model of behavior.

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?

A single dense sentence with no filler and a clear front-loaded summary ('In stock, and where'). The parenthetical is jargon-heavy but compact; it earns its place by describing the payload variants.

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?

The output schema covers return details, and annotations cover side effects, so the description does not need to repeat those. However, the lack of explicit parameter documentation, especially market, leaves an agent to guess part of the invocation contract.

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 0%, so the description must clarify parameters. It only clarifies decision_id (as the gate_transaction decision id). gtin is implied as the product identifier but never stated, and market is entirely unexplained.

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 identifies exactly what the tool returns—the availability block of a product, including in-stock status and location (banners, live product URLs, store counts). It ties the call to a specific prerequisite (gate_transaction answered allow), which distinguishes it from sibling retrieval tools like get_item or get_price.

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?

It clearly states when this tool is appropriate: after gate_transaction returns allow, and it names the required decision_id. It does not explicitly list alternatives or when-not conditions, but the gating condition gives concrete context for selection.

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