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

Annotations already flag destructive/non-idempotent/open-world, and the description adds genuinely new side-effect detail the annotations cannot convey: it delivers the reward, may email the subscriber, and may consume coupon codes. It stops short of stating whether the action can be undone or what happens on an already-unlocked reward.

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?

Three short sentences, front-loaded with the 'WRITE:' signal and the effect before the endpoint path. The raw endpoint duplication is slightly redundant but cheap and useful for agents mapping to the API.

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 destructive, non-idempotent mutation with no output schema, the description covers the key side effects but omits what a successful call returns and what happens on repeat invocation (non-idempotent), which is exactly the risk an agent needs to weigh before calling with confirm=true.

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 description coverage is 100% and every parameter is documented in the schema, including cross-references to the listing tools for obtaining uuid and reward_id. The description adds no parameter-level meaning beyond that, so the 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?

The description names a concrete verb (unlock) and resource (promoted-winner or one-off reward) and scopes it to a subscriber, plus the exact POST endpoint. It is clearly distinguishable from sibling `referralhero_list_unlocked_rewards` (a read) though it never explicitly contrasts itself with `update_reward_status` or `promote_subscriber`.

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 context is implied by 'delivers the reward' and the required `confirm` gate, but there is no explicit statement of when to choose this over `referralhero_update_reward_status` or `referralhero_promote_subscriber`, nor any when-not guidance (e.g. do not call if the reward is already unlocked).

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