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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered structurally. The description adds the calculation premise (waste driven by sales accept rate) but says nothing beyond that about edge cases, assumptions, or result shape. A 3 reflects useful framing layered onto strong 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?

Two sentences, front-loaded with the core purpose and free of filler. The trailing 'full version' link is short but is promotional rather than functional, slightly diluting the otherwise tight structure.

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 three-parameter, read-only calculator with a fully documented schema, the definition is adequate to invoke the tool. However, with no output schema and no description of the returned metric or its units, an agent cannot anticipate what it will receive.

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 all three parameters carry their own descriptions, so the schema does the heavy lifting. The description mentions the accept-rate concept but adds no units clarification or format guidance beyond what the schema already states.

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 ('Measure') plus resource ('marketing spend wasted on MQLs that sales rejects') and the calculation basis (accept rate between the two teams). An agent can tell it apart from sibling calculators like mql_calculator or ad_spend_waste_calculator, though the distinction is implicit rather than explicit.

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?

There is no when-to-use guidance, no exclusions, and no named alternative despite a dense sibling set of overlapping MQL/lead/waste calculators. The only secondary sentence is a promotional link, which provides no routing information.

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