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

With no annotations, the description carries the full burden. It does add real behavioral facts beyond the schema: paid auth mode ($0.005 per call via x402/MPP on Base or Tempo) and the POST endpoint. But it never states the return shape (presumably a validity boolean) or what happens on an invalid input, leaving the core outcome opaque.

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?

Heavily bloated with SEO metadata: origin URL, hostname, brand, family key, five redundant keyword lines, and a duplicated summary/source-description pair. It opens with an irrelevant origin URL instead of the purpose, and the same sentence appears twice, wasting an agent's context budget.

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 output schema and no annotations, the definition covers what it does, when to use it, and the payment model. It is still missing the return-value semantics and input format, which an agent needs to interpret results correctly.

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 0%, so the schema offers only 'value: string'. The description implies the parameter is the national ID / code melli, which is some added meaning, but gives no format guidance (digit count, Persian vs Latin digits, hyphens). Partial compensation only.

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 Summary line gives a specific verb+resource ('Validate an Iranian national ID (کد ملی) with the official checksum algorithm'), which is enough to separate it from siblings like iran_company_id, iran_mobile, or iran_sheba. However, this is buried under an origin-URL/hostname/brand preamble, so the agent must dig for the actual purpose.

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 supplies concrete when-to-use context ('Use for identity forms and KYC checks', signup-form validation, pre-onboarding checks). It does not name alternative siblings or state exclusions, but the use cases are specific enough that an agent can route here confidently.

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