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

Annotations only declare readOnlyHint/openWorldHint; the description adds substantial non-obvious traits: service items return isService:true and onHand:null, product.locations is omitted on single-location books, location totals need not reconcile with onHand, and on Counter companies the figure is stale as of the last day-close. This is exactly the kind of data-semantics disclosure annotations cannot carry.

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 purpose is front-loaded, and each sentence carries distinct information, but it is delivered as one dense paragraph of edge cases with no structural breaks, making it heavier than it needs to be for a single-parameter lookup.

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 does the heavy lifting on return semantics (onHand, isService, locations, day-close timing) and is largely complete. It omits what happens on a no-match or ambiguous query, which an agent would still need.

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% and the sole 'query' param is undocumented in the schema, so the description must compensate. It does: name, SKU, or exact barcode, with the 'exact' qualifier on barcode being a meaningful constraint. It leaves unaddressed how ambiguous name/SKU matches resolve.

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 specific verb+resource: 'How many units of a product you have on hand right now', and clarifies the lookup keys (product name, SKU, exact barcode). An agent can distinguish it from stock_movements or low_stock by implication (current level vs. history/threshold), but no sibling is named explicitly, so it stops short of a 5.

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 tells the agent how to search and how to interpret/report the result, but never states when to use this tool versus alternatives like low_stock or stock_movements, nor any exclusions. Usage is implied rather than directed.

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