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

Annotations already declare readOnlyHint=true, so the safe-read profile is covered and the description is consistent with it. The description adds genuinely useful context not in annotations: a $0.05 per-call cost and the precise exclusion rules (weekends, national holidays, joint-leave days). It does not describe error behavior for inverted or malformed date ranges.

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 zero waste, leading with the pricing signal and then the primary operation. Every clause — count working days, exclusions, list holidays — conveys distinct information.

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 two-parameter, no-output-schema tool, the description covers both what is computed and what is returned (working-day count plus the in-range holiday list), which is enough for an agent to call it correctly. Minor gaps remain around inclusive/exclusive range bounds and error handling, but nothing essential 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 coverage is 100%, with both 'from' and 'to' documented as ISO YYYY-MM-DD range bounds, so the schema carries the parameter burden. The description only restates that the tool operates on a range and adds no format, ordering, or inclusivity detail beyond the schema, which is the expected baseline.

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 — counting working days between two dates in Indonesia — plus the secondary output of listing in-range holidays. It is distinguishable from siblings like indonesia_holidays or indonesia_next_working_day by the range-counting scope, though it never names those alternatives 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?

The usage context is implied by 'count working days between two dates in Indonesia, excluding weekends, national holidays and joint-leave days', which tells an agent when the tool applies. There is no explicit statement of when not to use it or which sibling to pick for a single holiday lookup versus a range count.

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