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

Annotations already cover read-only, non-destructive, open-world. The description adds genuine behavioral detail beyond them: results are sorted lowest-first when max_quantity is used, plus the underlying endpoint. Pagination/limit behavior is left to the schema.

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: return shape first, filtering/sorting second, endpoint last. Nothing redundant and the most decision-relevant information is front-loaded.

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 simple read-only list tool with no output schema, the description supplies the return fields, the filter semantics and the sort behavior. Only minor gaps remain, such as what happens when limit truncates results.

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. The description earns an extra point by tying max_quantity to a sorting side effect (lowest first) that the schema does not state, clarifying what the filter actually changes.

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-and-resource pair ('stock on hand in the Zenfulfillment warehouse per SKU') and even names the returned fields (sku, quantity_on_stock). No sibling tool lists stock levels, so an agent can route here without ambiguity.

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 usage context: filter by SKU text and/or max quantity 'to find low stock'. It doesn't name an alternative or an explicit when-not condition, but no sibling overlaps enough to need one.

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