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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description need not repeat safety traits. It adds functional context about period and client breakdown but discloses no additional behavioral traits such as pagination or limitations. This is adequate given 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-sentence description with no waste: first sentence states the output components, second sentence gives example questions. Every word adds value and it is front-loaded with purpose.

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 two-parameter tool with an output schema, the description fully covers scope, period semantics, and optional breakdown. It does not need to explain return values because the output schema exists.

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%, so both period and byClient are fully defined in the schema. The description adds only 'over a period' and 'broken down by client,' which mirror the schema. Baseline 3 applies because schema carries the semantic load.

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 explicitly defines the tool as computing revenue vs. costs, net profit, and margin over a period, with optional client breakdown. It answers concrete business questions ('am I profitable this year?' / 'which client is most profitable?'), clearly distinguishing it from sibling revenue or cost summary tools.

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?

Provides clear use cases via example questions, indicating when to use the tool. It does not explicitly name alternatives or exclusions, but the purpose and examples give strong contextual guidance.

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