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

With no annotations provided, the description carries the full transparency burden. It discloses important behavior: Hijri-calendar feasts are read from an announced table, and years without official announcements return `confirmed:false` rather than guessed values. It does not describe the full return shape or behavior when both `addDays` and `end` are supplied, but the core behavioral caveat is well covered.

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?

The description is three short sentences, front-loaded with the core purpose and followed by a necessary caveat and use-case list. Every sentence earns its place; the final fragment is slightly informal but not wasteful.

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?

There is no output schema, so the description should explain return values more fully; it only mentions `confirmed:false` without describing the overall response structure. It also does not address edge cases like supplying both `addDays` and `end`, or whether start/end dates are inclusive. For a 4-parameter tool with no annotations and no output schema, this leaves some important gaps.

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%, so the baseline is 3, but the description adds meaning by defining business days in the context of Turkish holidays and half-day eves, which directly clarifies how `addDays` and `countHalfDaysAsWork` should be interpreted. It does not clarify the relationship/conflict between `addDays` and `end`, but the schema already documents each parameter individually.

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 uses a specific verb-resource pair: 'Adds business days or counts them between two dates' and clearly scopes it to Turkish public and religious holidays. This distinguishes it from the sibling validation and lookup tools, which serve entirely different purposes.

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 description explicitly names target use cases: 'delivery promises, SLA clocks, payment terms and shipping estimates.' It does not mention when not to use the tool or name alternatives, but the context is clear enough for an agent to select it appropriately.

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