validate_pan

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

Annotations already declare readOnlyHint=true and idempotentHint=true, indicating the tool is safe and idempotent. The description does not add significant behavioral context beyond the annotations. It does not describe return format or any edge cases, but for a validation tool, this is acceptable given the annotations.

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 exceptionally concise with two sentences. The first sentence defines the core functionality, and the second sentence provides usage context. No word is wasted.

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 tool's simplicity (single parameter, clear purpose), the description is complete. It covers what the tool does and when to use it. The presence of an output schema and annotations means the description does not need to explain return values or safety concerns further.

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 input schema already provides a thorough description: '10-char PAN (spaces/hyphens allowed)' with max and min lengths. The description does not add further value about the parameter. Since schema coverage is 100%, the baseline is 3.

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 clearly states the tool validates Indian PAN format and decodes the entity type from the 4th character. It uses specific verbs ('validate' and 'decode') and identifies the resource ('Indian PAN'). This distinguishes it from sibling tools like 'decode_pan_type' (which may only decode) and 'bulk_validate_pan' (for bulk operations).

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 provides context by stating that the tool should be used when normalizing tax identity records in KYC, invoicing, or vendor onboarding. Although it does not explicitly mention when not to use it or list alternatives, the usage guidance is clear and relevant.

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