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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds that the output concerns revenue concentration and per-customer averages, which is useful context, but says nothing about determinism, units, or the shape of the result. Adequate but not rich.

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 first sentence is dense and front-loaded with the core purpose. The second sentence is a promotional link to an external calculator site, which does not help an agent invoke the tool and dilutes an otherwise efficient definition.

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, annotation-covered computation with no output schema, the description conveys what is computed but not what the result looks like or how it should be interpreted. It covers the essentials without fully compensating for the missing output 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 all four parameters (smbCount, smbAcv, entCount, entAcv) are individually documented in the schema. The description adds no syntax, unit, or format detail beyond that, 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?

States a specific verb and resource (break ARR down by SMB vs enterprise) plus the purpose of the output (revenue concentration, per-customer averages). This clearly distinguishes it from sibling ratio tools like mrr_to_arr_calculator or arr_multiple_calculator, though it never names a sibling explicitly.

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 prerequisite, and no routing to alternatives such as mrr_bridge_planner or arr_multiple_calculator. A reader must infer from the description alone that this is for segment-weighting analysis.

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