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

No annotations are provided, so the description carries the full burden. It usefully discloses pricing and the payment mechanism ($0.005 per call, USDC on Base), which is real value beyond structured fields, and 'check digit' hints at the algorithm. However it says nothing about the return result (boolean/valid-invalid shape) or behavior on malformed input.

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 that front-loads the core action and folds the cost note into a compact parenthetical. Every element earns its place with no filler.

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 one-parameter validator with no annotations and no output schema, the description covers the action, the target, and cost, but omits return semantics and failure behavior. Adequate but with clear gaps an agent would have to discover by calling it.

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 'value' parameter, and the description adds no syntax or format detail beyond what the schema already states ('10-digit national ID'). Baseline 3 applies when the schema does the heavy lifting.

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 (Iranian national ID / کد ملی), and the 'check digit' qualifier pins down exactly what is being validated. This clearly distinguishes it from the sibling validators for bank cards, company IDs, mobile numbers, etc.

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 by the resource name; there is no explicit guidance on when to use this versus the many sibling validators, nor any stated preconditions. Given the self-describing ID type, an agent can infer the right context, but nothing is stated.

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