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

With readOnlyHint=true already covering the safety profile, the description adds useful behavior: the stock-module prerequisite, the case-sensitive matching rule for warehouse_name, and the all-products fallback when unfiltered. It does not mention pagination or result shape, but that is a minor gap given the annotation coverage.

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, front-loaded sentences with no filler; scope, prerequisite, and filters appear in order of importance. The trailing 'GET /stocks' endpoint reference is minor implementation noise but does not detract materially.

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 filtered query with no output schema, the description supplies prerequisite, filter semantics, and default behavior. What remains unsaid (return format, pagination) is minor against an annotation that already certifies a safe read.

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?

At 50% schema coverage, the description carries extra weight and does list all three optional filters by name and explains the default when none are supplied. It reinforces the case-sensitivity of warehouse_name (already in schema) but leaves product_name/product_code without syntax detail, which is acceptable for free-text identifiers.

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 ('Stock quantities per warehouse as of a date') with clear scope. No sibling tool retrieves stock, so the agent can distinguish it from the list/get/estimate/invoice cluster immediately. The description also names the parameter surface, making purpose unambiguous.

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 clear prerequisite ('needs the SmartBill stock module') and specifies the default behavior when filters are omitted ('No filters = all products in all warehouses'). It doesn't name an alternative sibling, but none exists in the tool set, so there is little more to say.

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