validate_upi_vpa

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

The description discloses the core behavior: format validation and PSP/bank identification via suffix mapping. With no annotations, it provides good transparency, though it omits details on error handling or limitations (e.g., doesn't check VPA existence).

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?

Single sentence, no wasted words, front-loaded with action (validate) and result (identify). Example is concise and illustrative.

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 tool with one parameter and an output schema, the description fully covers what the tool does. It explains format and mapping, which is sufficient given output schema exists.

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%, but the description adds value by explaining the expected format ('username@psp') and providing an example that maps suffix to PSP and bank. This enriches parameter understanding beyond the bare schema.

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 UPI VPA format and identifies PSP and bank from handle suffix, with an explicit example. This distinguishes it from sibling tools that handle other identifiers (IFSC, PAN, GSTIN, etc.).

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?

Usage is implied (when you have a UPI VPA), but no explicit guidance on when not to use it or alternatives. Sibling tools are different, but no comparative instructions.

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