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

Annotations already mark the tool as read-only, idempotent, and non-destructive. The description adds valuable behavioral detail beyond that: default returns full details, non-sellable products can be included with status tags, and unpriced products return a status rather than a billable number. This is useful edge-case context with no contradiction.

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 three tight sentences with no filler. It front-loads the core action and resource, then covers defaults, the optional parameter, and an edge case without redundancy.

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 read-only listing tool with an output schema, the description fully covers the default behavior, the optional flag, and the unpriced-product edge case. Nothing an agent needs to decide whether to call this tool or interpret its results 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 coverage is 100%, so the baseline is 3. The description adds meaningful nuance for include_non_sellable by explaining the status tagging and the behavior for products without a settled price, going beyond the schema's short boolean description. The agent_token parameter remains schema-only, which is acceptable since the schema already documents 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 opens with a specific verb and resource: 'List the Velarion product catalog.' It also enumerates what is returned (name, price, currency, delivery type, latency, caveats), making it clearly distinct from the compensation-focused sibling tools.

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 tool is for listing catalog products and explicitly explains when to use include_non_sellable=true. It does not explicitly name alternatives or exclusion criteria, but the sibling tools are in a different domain, so the intended usage is unambiguous.

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