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

The annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is fully covered. The description adds the shape of a result row (unit, quantity, minimum, low-stock flag) and the 100-item ceiling, but the output schema already defines the return shape and the schema already caps limit at 100. What remains undisclosed is whether the list is paginated beyond the limit or how ordering works.

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?

Three short sentences with zero padding: the when-to-use cue comes first, the return summary second, and the exclusion last. Nothing could be removed without losing information.

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 list tool with an output schema and fully described parameters, the description covers the trigger, the result contents, and the size ceiling. The small residual gaps are pagination behavior and ordering, which are minor given that the output schema carries the return 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 100%: gymId, limit, search, and lowStockOnly are each documented in the schema, and the description adds no format, default, or edge-case guidance beyond what is there. The mentions of the low-stock flag and the 100-item cap restate schema content rather than extend it, so the baseline 3 applies.

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 specific verb and resource: it lists stock items and their remaining quantities for a gym, and explicitly carves out retail prices as out of scope. It is clear what the tool does, though the only differentiation offered is against pricing rather than against a named sibling such as set_inventory_quantity.

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?

"Use this when someone asks how much of a product or supply is left in the gym's stock or what is running low" gives a concrete triggering question type, and "Not for retail prices" sets a boundary. It stops short of naming the alternative tool for changing quantities, so the agent must infer that writes belong elsewhere.

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