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

Annotations already establish read-only, non-destructive, open-world safety, so the bar is lower. The description adds genuine value beyond them by enumerating the returned fields (reward name, status, value, subscriber email/id, coupon code, transaction), which matters since there is no output schema.

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?

Front-loaded with the resource, followed by a field list and a filter hint; every sentence contributes. The field enumeration is dense but earns its place given the absence of an output schema.

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?

Because there is no output schema, describing the returned fields is the key completeness contribution, and the definition does that. Pagination and filtering are covered by the schema, leaving little essential missing.

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%, so all four parameters (uuid, page, status, per_page) are already documented in the schema. The description restates the status enum and campaign-wide scope but adds no syntax or format detail beyond the schema, so baseline 3 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?

States a specific verb (list unlocked rewards) with clear scope ('across a whole campaign') and distinguishes itself from per-subscriber scoping siblings like list_subscriber_rewards. It does not explicitly name the alternative tool, so sibling differentiation is implicit rather than stated.

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?

'Filter by status to find rewards still to pay out' hints at a use case, giving some when-to-use context. But it never explicitly names list_subscriber_rewards or list_campaign_rewards as the alternative, so the agent must infer which scoping tool to choose.

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