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

With no annotations, the description carries the burden. It discloses that it performs Luhn validation and splits TAC/serial, which is useful. However, it does not state whether it is purely offline (as hinted) or any side effects, but since it is validation, it is likely safe. It does not contradict annotations (none provided).

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 description is a single compact sentence that front-loads the main purpose and key behavior. It is concise and efficient, though it could be slightly more explicit about input format.

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?

Given the simplicity (1 param, no required params) and the absence of annotations, the description is still incomplete: it does not specify input format, expected length, or what the output looks like (though output schema exists). It lacks enough context for an agent to confidently call the tool.

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 schema has one parameter 'q' with a default but no description. Schema coverage is 0%. The description does not explain what 'q' should contain (e.g., the IMEI string, formatting requirements). This is a significant gap for a tool with a single undocumented parameter.

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 description states a specific action (validate IMEI using Luhn algorithm) and resource (IMEI), and mentions splitting TAC/serial. It is clear and distinguishes from many generic tools, though it does not explicitly contrast with siblings like 'luhn' or 'tac' (which may exist).

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 implies it is used for IMEI validation, but offers no explicit guidance on when to use this tool versus alternatives like 'luhn' (generic Luhn check) or other device-related tools. It does not state exclusions or prerequisites.

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