validate_gstin

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

Annotations already declare readOnlyHint and idempotentHint, so the tool is known to be safe and idempotent. The description adds value by revealing checksum verification and decoding behavior, which enriches the agent's understanding beyond structural hints.

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 two sentences: first states action and key feature (checksum verification), second provides usage context. Every sentence is purposeful, no fluff, and front-loaded with crucial information.

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 output schema exists (context signals confirm), the description does not need to detail return values. It covers purpose, usage, and a behavioral trait (checksum). Missing error conditions or edge cases, but overall complete for a validation tool with rich annotations.

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 coverage is 100% and the input schema already describes the gstin parameter (type, length, allowed characters). The description adds no further parameter-level details, so the baseline score of 3 applies; it does not improve or worsen parameter understanding.

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 and decodes an Indian GSTIN with checksum verification, making the action and resource specific. It distinguishes from sibling validators like validate_pan or validate_aadhaar by explicitly naming GSTIN and mentioning checksum, with use case examples.

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 specifies when to use the tool: 'before invoicing, reconciliation, or compliance workflows.' While it provides clear context, it does not explicitly exclude alternatives or note when not to use it, but the sibling tool list helps differentiate.

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