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

Even with empty annotations, the description discloses the key behavioral trait: the voucher is not redeemed, only validated. It also provides the exact format of the voucher code, which is critical for correct invocation. This goes beyond a simple statement of purpose.

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 concise, front-loaded with the core purpose, and uses standard doc-style sections for parameters and return values. Every sentence adds value with no fluff.

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?

With an output schema present, the description need not detail return structure. It covers the tool's action, the key non-redeem behavior, and the parameter format. This is complete for a simple validation 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 provides only a string type with no description, but the description fully explains the voucher_code parameter including format ('4 sets of integers') and an example. This adds significant meaning beyond the input 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 uses a specific verb ('Performs a validation') and names the exact resource ('Netfluid voucher code'). It clearly distinguishes this from redemption by explicitly stating 'not redeemed, only validated', setting it apart from sibling tools like account_merchant_voucher_redeem.

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 when to use this tool: for validating a voucher without redeeming it. This creates a clear context and implies that redemption would require a different tool, though no specific alternative is named.

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