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

Annotations already establish readOnly, idempotent, non-destructive behavior, so the safety profile is covered. The description adds the formula and the dual-unit output (N·m and lb-ft), which is modest value; it adds little else beyond what annotations and the output schema 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?

Compact and front-loaded: purpose, formula, usage, inputs, outputs in short sentences with zero filler. The trailing 'See list_bundles' sentence is slightly promotional and not strictly necessary, keeping it below 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 values need not be explained, and the description still supplies the formula. However, the kW-vs-watts input discrepancy leaves the single most important invocation detail (input unit) ambiguous, which is a meaningful gap for a 2-parameter tool.

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 would be 3, but the description states 'Inputs: power kW' while the required parameter is power_w documented as 'Power watts'. This unit mismatch actively misleads the agent on the input unit, degrading rather than adding semantic value.

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 ('Compute motor torque from power and RPM') and even gives the governing formula, so an agent can tell what the tool produces. It does not explicitly differentiate itself from the hundreds of sibling calculate_* tools beyond the descriptive name, so it stops short of a 5.

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?

'Use for mechanical sizing' gives a rough context but no when-not conditions and no named alternative. The 'See list_bundles' pointer is a cross-reference to an unrelated discovery tool, not an alternative for the same task, so usage is only implied.

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