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

With no annotations, the description carries the full burden. It does disclose a valuable behavioral trait: the discount applies to room price only, excluding extras and breakfast. However, it says nothing about case sensitivity, whether validation holds or consumes the code, or how an invalid code is signalled.

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 tight sentences with the core action first and the return semantics second. Zero filler, nothing repeated from the schema.

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 usefully covers return values (valid flag and discount percentage) and scopes the discount correctly. It stops short of describing invalid-code behavior or error surfaces, which is a minor gap for a single-parameter read tool.

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% for the single 'code' parameter, so the schema already documents it. The description adds no format, casing, or length constraints beyond what the schema provides, so baseline 3 applies.

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 ('Validate') and resource ('Yasha Hotel promo code'), and goes further by describing the return semantics (validity plus percentage discount). No sibling tool overlaps with code validation, so differentiation is inherent, though no sibling is named 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?

There is no explicit when-to-use guidance and no reference to alternatives such as create_booking or get_price_calendar. Usage is only implied by the tool name and the discount description, leaving the agent to infer the calling context.

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