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

Annotations already declare readOnlyHint, openWorldHint=false, and destructiveHint=false, so safety is covered. The description adds 'deterministic' and 'no signup' context, which is useful, but says nothing about output shape or bounds on inputs.

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?

A short, front-loaded fragment with no waste, though it is too terse to carry much meaning.

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 computational tool with zero schema descriptions and no output schema, the description leaves units, scaling, and return shape unspecified; an agent cannot confidently call it correctly.

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% and the description adds no meaning for the three required parameters (costPerClick, conversionRatePct, contributionPerOrderUsd) – an agent must infer units and how conversionRatePct is scaled.

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 the resource and outcome (customer acquisition cost and break-even click price), giving an agent a specific sense of what is computed. It is distinguishable from siblings like penny_margin or penny_marketplace_profit, though it doesn't name the formula or units.

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?

'Free, no signup, deterministic' hints at usage context, but there is no explicit when-to-use vs alternatives guidance among the sibling pricing/profit tools. 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.