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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower, yet the description adds real value: it discloses holiday-skipping behavior, that skipped holidays are returned, and that shared cache/limits apply. It goes beyond the structured safety hints with operational context.

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 compact sentences with the core behavior front-loaded; nothing is wasted. The trailing 'GET /v1/add' reference is slightly cryptic for an agent but does convey engine/cache continuity efficiently.

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 six-parameter date-math tool with an output schema already covering return structure, the description supplies the essential behavioral context (weekend/holiday skipping, negative direction, shared limits). An explicit pointer to sibling tools for adjacent operations is the only meaningful gap.

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 the schema already documents all six parameters, including the negative-days and holiday-type semantics. The description's mention of negative subtraction and country/region merely reinforces what the schema states, so baseline 3 is 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+resource ('add/subtract business days to a date') with the exact mechanic (skipping weekends and public holidays). This clearly distinguishes it from siblings like business_days_between and is_business_day, which count or test rather than offset.

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?

It implies the subtract use case via negative numbers and orients the agent with 'same engine, cache and limits as GET /v1/add', but never states when to choose this over business_days_between or is_business_day. Usage context is implied rather than explicit routing.

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