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

Beyond the annotations (which only declare write/safe/local), the description discloses replace-not-duplicate semantics on repeated calls, the refusal behavior when the supplier doesn't carry the item, the company-wide default vs per-outlet override model, and the critical non-effect that nothing is ordered or emailed automatically. This is exactly the behavioral context structured fields 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?

Five sentences, each carrying distinct information (trigger, idempotency, precondition, override rationale, safety caveat), with the core action front-loaded. No filler.

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 write tool with no output schema, the description covers what it mutates, what it refuses, how repeated calls behave, and what downstream action it does and does not trigger. An agent has everything needed to call it safely.

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 coverage is 100% so the baseline is 3, but the description adds meaning the schema lacks: what lowStockPoint/reorderQuantity jointly do, that thresholds are company-wide by default, and that outletOverrides exists specifically for outlets that differ. It stops short of detailing the inherit-on-omit fallback.

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 action ('watch one item and suggest reordering it when stock runs low') with the exact trigger (below lowStockPoint) and quantity (reorderQuantity). Clearly distinguishable from hub_remove_reorder_rule and hub_get_reorder_suggestions in the sibling list.

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 a concrete precondition (supplier must already carry the item, verified via get_supplier_items) and explains when to use outletOverrides ('a busy store may need a higher one than a quiet one'). It does not explicitly name the sibling to use for removal or suggestion retrieval, so it stops short of full when/when-not routing.

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