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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuine semantic context beyond that: it explains what the 'untracked count' means (SKUs Shopify does not track, in no band, not a problem) and what the payload contains (days of cover, units left, nearest-to-running-out SKUs). It stops short of noting any size/limit on the returned SKU list.

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?

Front-loads what is returned, then usage, then the edge-case clarification, then the alternative pointer — a sensible ordering. The untracked-count sentence is slightly wordy ('they are in no band and are not a problem, they are simply uncounted') but each clause does add meaning.

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?

With no output schema, the description must convey the return shape, and it does: band definitions, days of cover, units left, the closest-to-running-out SKUs, and the untracked count. No parameter documentation is needed since the tool takes none.

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 takes zero parameters, so the schema carries no semantics to explain and the description needn't document inputs. Baseline for a parameterless tool, with no compensating information needed.

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?

States a concrete resource (stock levels per SKU) and enumerates the four output bands with their thresholds, so the agent knows exactly what the tool returns. It also names the sibling get_top_products as a different concern, distinguishing itself without requiring schema inspection.

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?

Explicitly says 'Use for any question about stock, restocking, or what will run out,' covering the trigger conditions broadly, and routes the adjacent-but-different question (best sellers) to get_top_products. Both when-to-use and the alternative are stated.

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