check_inventory

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered by structured data. The description adds one useful semantic detail beyond that — that low_stock_only compares against each item's reorder level. It says nothing about result size, pagination, or default behavior, but with annotations carrying the behavioral load a 3 is appropriate.

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?

Two short sentences, front-loaded with the resource and then immediately the two usage modes; nothing is wasted. The opening fragment 'Stock levels.' is compressed to the point of being slightly cryptic, which keeps it from a 5.

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?

An output schema exists, so return format need not be described. Combined with annotations and the two-mode usage guidance, an agent has enough to call it correctly. The only real gap is the no-argument default path, which is left implicit.

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%, so the description must carry the meaning, and it does explain both parameters: sku selects a single item, low_stock_only=true filters to at-or-below-reorder items. It also clarifies the threshold semantics ('at/below their reorder level'), which the schema does not. It does not address SKU format or interaction between the two params, keeping it short of a 5.

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 names the resource (stock levels) and, through its two usage clauses, makes clear it retrieves inventory data by SKU or by low-stock filter. It lacks an explicit verb (the fragment 'Stock levels.' is terse), but the intent is unambiguous. The siblings are all unrelated domains (contacts, tasks, deals, orders), so no sibling differentiation is needed.

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?

It states two concrete invocation modes: pass a SKU to get one item, or set low_stock_only=true for items at/below reorder level. That is explicit guidance for both parameters. It stops short of a 5 because it never says what happens with no arguments (the default path) or whether the two modes can be combined.

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