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

Annotations indicate mutation (readOnlyHint=false) and non-destructive (destructiveHint=false). The description adds 'one-time' constraint, which is a key behavioral trait beyond annotations. However, it does not detail error handling or side effects.

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-loads the action and outcome. Perfectly concise for the tool's simplicity.

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 low complexity (1 parameter, output schema exists), the description covers the main behavioral constraint ('one-time') and purpose. Minor lack of explicit prerequisites or error cases, but adequate for a simple redeem action.

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 schema already describes the parameter 'code' as 'The referral code to redeem for one-time bonus credits.' The description does not add new semantic information beyond reinforcing the purpose, so baseline score applies.

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 action ('Redeem'), the resource ('referral code'), and the outcome ('claim your one-time new-user bonus credits'). It distinguishes from sibling 'get_referral_status' which checks status rather than redeeming.

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?

Implies usage for new users with a referral code to claim bonus credits, but does not explicitly state when not to use it (e.g., if already redeemed) or mention the alternative 'get_referral_status' for checking eligibility.

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