Cancel or refund a coupon operation

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

Annotations already flag destructiveHint, idempotentHint and openWorldHint, so the bar is lower, yet the description still adds real value: it discloses that counters and budgets are released, that the backend reclassifies the record as cancellation or refund depending on payment state, and that no money moves at the payment provider. Only the failure/edge behavior for an already-reversed operation is left implicit.

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 with the core action and side effects front-loaded, and the negative constraints ('no reason or partial amount', 'does not move money') placed last. The middle sentence about backend classification is dense but each clause is informative.

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 one-parameter destructive mutation with full annotation coverage and no output schema, the description covers what is destroyed, what is released, and what does not happen downstream at the payment provider. It could be more complete about preconditions (operation must be in a redeemable/redeemed state) but nothing essential for invocation is 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% and the single operation_id parameter is documented as coming from a successful redeem, so the schema carries the load. The description adds only the implicit constraint that exactly one operation is affected, which is the baseline expectation rather than extra meaning.

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 ('Fully reverse') and resource ('one coupon operation') with explicit scope ('fully'), plus the side effect of releasing usage counters and budgets. It does not name the sibling it differs from (e.g. revoke_coupon_issuance vs. this operation-level reversal), so it falls short of full sibling differentiation.

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 by 'one coupon operation' and the schema note that operation_id comes from a successful redeem, and the description rules out partial reversals or reason arguments. However, it never explicitly says when to use this versus revoke_coupon_issuance or what state the operation must be in, leaving the agent to infer routing.

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