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

Annotations already declare readOnlyHint, idempotentHint, non-destructive; the description adds value beyond them by explaining that quantities are derived from live lead-time, MOQ, case-pack, open-PO, location and supplier MOV logic, and by disclosing the connected-store/sign-in prerequisite. It doesn't discuss result ordering, freshness, or what happens when no store is connected beyond a sign-in prompt, which keeps it off a 5.

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 tight sentences, front-loaded with the triggering question, followed by computation provenance, the negative scope, and the auth prerequisite. No repetition of schema or annotation content; every clause carries 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 recommendation tool with an output schema and fully documented params, the description covers intent, computation basis, non-mutation and auth requirement — enough to call it correctly. Minor residual gaps (ordering of results, behavior on an empty inventory, how the sign-in prompt surfaces) are not addressed.

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%, so limit, priority and supplier are already fully documented with defaults, enum values and nullability. The description adds no extra parameter meaning (e.g. what 'warning' vs 'critical' maps to operationally, or how supplier matching behaves), 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?

States a specific verb+resource ('reorder recommendations') and immediately names the merchant intents it answers (what to reorder, how much to buy, which critical/warning items need action). It also explicitly disclaims PO creation and points at the sibling territory of list_purchase_orders, so an agent can separate it from ordering tools without opening a schema.

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?

Gives concrete trigger phrases and one explicit exclusion ('this tool does not create a PO'), which is real routing guidance rather than implied usage. It stops short of naming which sibling to use instead for single-item math (calculate_order_quantity / calculate_reorder_point), so it isn't fully closed-loop.

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