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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description adds one genuinely useful behavioral fact, that the result depends on the Swedish holiday calendar and that days may be subtracted, but it does not explain edge-case behavior (whether the start date counts, how mode affects the holiday set).

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?

A single sentence with the core operation front-loaded, followed by the calendar qualifier and an example. Nothing is padded or redundant.

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 three-parameter, no-output-schema tool with full annotation coverage, the description is adequate but thin: it never states the return value (presumably a YYYY-MM-DD date) and does not clarify what distinguishes bank mode from work mode, which is the only non-obvious parameter choice an agent must make.

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%, with date format, the integer/negative convention and the bank/work enum all documented in the schema. The description's parentheses restate the subtraction case already covered by 'integer, may be negative', adding no syntax or format detail beyond the schema.

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 gives a specific verb (add/subtract) and resource (business days to a date) and pins down the holiday calendar as Swedish, which cleanly separates it from count_business_days and swedish_holidays. It stops just short of naming the sibling it complements, so it is clear but not fully differentiated.

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?

Usage is only implied through the parenthetical example ('payment due dates'), which hints at a finance context but never states when to choose this over count_business_days or swedish_date_info. No exclusions or prerequisites are given.

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