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

Annotations already signal readOnlyHint=true and destructiveHint=false, so the safe-read behavior is covered. The description adds the output metrics and input basis but does not reveal formula assumptions, precision, or response shape; that is acceptable given the annotations, so this is average rather than poor.

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?

The functional sentence is compact and front-loaded. The second sentence is promotional ('Free tool by Tru-Stock AI — URL') and adds no call-time value, warranting a small deduction.

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 calculator with read-only annotations and complete schema descriptions, the description names the key outputs and inputs. It does not spell out formulas or output units, but an agent has enough to select and call the tool correctly, with the optional revenue parameter documented in the schema.

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% and the schema already defines cogs, annual revenue, and average inventory value. The description adds little beyond naming the same inputs, so the baseline of 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?

The description names a specific action ('Calculate') with concrete outputs ('inventory turnover ratio, days sales of inventory (DSI) and GMROI') and identifies the required inputs ('COGS and average inventory value'). This clearly distinguishes it from sibling tools like calculate_carrying_cost or calculate_reorder_point, which target different metrics.

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?

The first sentence gives clear conditions for use: compute turnover, DSI, or GMROI from COGS and average inventory. It does not explicitly state when not to use it or point to an alternative sibling, but the metric-specific wording makes the intended context obvious.

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