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

Annotations already declare readOnlyHint=false, idempotentHint=false and openWorldHint=true, so the safety profile is covered. The description still earns credit by explaining the real-world consequence — the coupon goes live and is immediately redeemable — and by spelling out the duplicate-creation risk rather than merely restating the flag, plus citing POST /coupons.

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 tight sentences, front-loaded with the write marker and the highest-risk fact (live, immediately redeemable). Every clause carries information: scope, side effect, option summary, and idempotence caveat.

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 9-parameter mutating tool with full schema coverage and annotations, the description covers creation semantics, constraints and side effects well. The one gap is the return value: with no output schema, an agent gets no hint that a coupon/ID comes back, which matters for chaining a follow-up get_coupon.

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 the baseline is 3; the description adds value by grouping the optional axes ("limited to one form, to a number of uses, and to an expiry date") and by tying discount_type to discount_value as a single "fixed amount or percent" decision. It does not add format details for expires or the -1/unlimited convention, but the schema handles those.

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?

Opens with an explicit verb+resource ("create a discount coupon") bounded to the live TicketSpice account, and the "WRITE:" prefix plus the effect ("can be redeemed by ticket buyers right away") distinguishes it instantly from the get_/list_/delete_coupon siblings.

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 "WRITE:" marker and the non-idempotence warning ("calling it twice creates two coupons") give an agent clear operational context for when this applies versus the read-only coupon siblings. It stops short of explicitly naming an alternative or a verification step (e.g., list_coupons after creation), so it is strong but not complete.

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