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

With no annotations, the description carries full behavioral burden. It usefully discloses the validation algorithm (modulo-7 check digit per IATA Resolution 600a) and format expectations, but says nothing about return values, whether validation is offline/local, or failure modes.

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 front-loaded sentence with no filler; the standard reference is the only slightly expendable clause. Appropriate size for a one-parameter tool.

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 simple one-param validator the description is nearly adequate, but with no annotations and no output schema it leaves the return shape (boolean vs. structured result) and any error behavior undefined.

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% and the single parameter is well documented in the schema, so baseline is 3. The description adds genuine meaning by spelling out the internal structure (3-digit airline prefix + 8-digit serial + modulo-7 check digit) that the schema only shows by example.

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 (IATA air waybill number), then decomposes the expected format into prefix, serial, and check digit. This clearly separates it from siblings like validate_iban or validate_lei, though it never names an alternative 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?

No when-to-use statement, no prerequisites, and no mention of alternatives among the many sibling validators. The phrase 'for air cargo freight documentation' faintly implies context but does not tell an agent when this tool should be chosen over another.

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