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

No annotations are provided, so the description carries the full burden. It discloses the data returned but does not explicitly state that it is a read-only operation, mention pagination, or any access constraints. For a stats tool, this is somewhat adequate but leaves behavioral assumptions unstated.

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, concise sentence that front-loads the main purpose and lists key output dimensions without any fluff. Every word contributes to understanding the tool.

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 zero-parameter stats tool, the description covers the main metrics and grouping dimensions, giving the agent enough context about the return values even without an output schema. It could explicitly mention that it's an aggregate view, but the content is sufficiently complete.

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 tool has zero parameters and an empty schema, so there is no parameter meaning to add. The description appropriately focuses on the output, and the baseline for 0-parameter tools is 4.

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 clearly states the tool provides global inventory statistics, specifying the exact dimensions (active auctions by source, province, type, average prices, enrichment coverage). This distinguishes it from sibling tools that handle searches, comparisons, or detailed views.

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 implies the tool is for aggregate inventory metrics, but it does not explicitly state when to use it versus alternatives or provide exclusions. The context from sibling names helps, but no direct usage guidance is given.

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