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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description adds real behavioral detail: it flags when a higher tier is cheaper in total, surfaces Executive Suite and Rollout Pack alternatives, and clarifies it does not place an order. This is output-level behavior an agent needs and cannot get from the annotations.

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?

Three tight sentences, front-loaded with the core calculation, followed by behavior and routing. Every clause carries information; no filler.

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?

With no output schema, the description compensates by describing what the tool produces (tier-cheaper flags, Executive Suite and Rollout Pack alternatives) and what it explicitly does not do. Nothing essential for correct invocation is missing.

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 parameters (seats, coBranding) are already documented in the schema. The description restates the 1-500 range and co-branding but adds no syntax or defaulting detail beyond what the schema provides, making the baseline 3 appropriate.

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 ('Calculates the AI at Work cost') plus scope ('for a given number of seats (1-500)') and an optional modifier (co-branding). It is clearly distinguishable from siblings like get_pricing and assess_ai_readiness, which are named or implied.

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?

Explicitly states a when-not ('It does not take an order') and routes the agent to an alternative ('To check readiness, use assess_ai_readiness'). It doesn't explain when to prefer this over get_pricing, so it stops short of a full when/when-not/alternatives treatment.

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