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

With no annotations, the description carries the full burden. It usefully discloses the paid auth mode and exact price ('$0.005 per call ... via x402 or MPP') and the two validation algorithms applied, but it says nothing about the return format, error/invalid-input behavior, or rate limits.

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 provider metadata (origin URL, hostname, brand, aliases, family key, endpoint, keyword lines), and the 'Summary' and 'Source description' sentences are verbatim duplicates. The actual purpose is buried after boilerplate rather than front-loaded.

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-parameter validator with no output schema, the definition conveys function, use cases, and cost, but it never explains what the validation result looks like. Since no output schema exists, that gap should have been filled by the description.

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?

The single parameter 'value' has 0% schema description coverage, so the description must compensate and does not. It implies the input is a SHEBA/IBAN number but gives no format guidance (IR prefix, length, spaces, digits), leaving the agent to guess.

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 states a specific verb and resource: 'Validate an Iranian SHEBA (IRAN IBAN) account number with both IBAN mod-97 and Iran-specific checksum checks.' This distinguishes it from sibling validators like iran_bank_card or iran_national_id, so an agent can pick it without opening the schema.

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?

Three explicit use cases are given ('before a bank transfer', 'check for a valid mod-97 checksum', 'confirm a bank account number is well formed'), which clearly frame when to invoke it. There are no exclusions or named alternatives, so it falls short of a 5.

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