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 that the tool is paid, the auth mode, and the price ($0.003 per call via x402/MPP), which is real behavioral context. However it says nothing about failure behavior for malformed numbers or what the response shape looks like beyond the operator.

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?

The definition is dominated by boilerplate metadata: origin URL, hostname, brand, provider aliases, family key, endpoint, seven redundant keyword lines, and a source description that repeats the summary verbatim. The one functional sentence is not front-loaded, and the repeated keywords earn no space.

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 single-parameter validator with no output schema, the description covers the input format, the output (operator), and the cost/auth model, which is enough for an agent to call it correctly. Only edge-case behavior for invalid input is missing.

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% with a single undocumented 'value' string parameter. The description partially compensates by specifying the expected format (09xxxxxxxxx), but adds no constraints on length, digit-only content, or whether the +98 prefix is accepted.

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 and resource: validate an Iranian mobile number and report its operator (MCI, Irancell, MTN, Rightel). This clearly separates it from the iran_landline sibling, though the actual purpose is buried beneath a metadata dump of origin URL, hostname, brand and family key.

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 'Use case' lines imply when to reach for it (validate a number, identify the carrier, sanity-check before SMS), but there is no explicit when-not guidance and no sibling alternative is named (e.g. iran_landline for landlines). Usage is implied rather than directed.

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