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

With no annotations, the description does real work: it discloses partial-update semantics, the clear_* flags used to null caps, that renaming survives existing redemption rows keyed on coupon id, and that operator proof is required. Gaps remain (what happens to unmentioned fields, whether other fields can be cleared), but the mutation behavior is substantially disclosed.

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?

The definition is short and front-loads the core action before the nuances. Each sentence earns its place and no filler is present.

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?

An output schema exists, so return values need not be explained, and the auth/clear-semantics notes are useful. But for a 10-parameter mutation with 0% schema coverage and no annotations, the description leaves too many parameters and edge behaviors undocumented to be considered complete.

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 0% across 10 parameters, so the description must carry the burden, yet it only meaningfully explains clear_uses_per_patron, clear_total_uses, name (rename), and hints at the 'proof' parameter. coupon_id, dpop_token, total_uses, valid_from, valid_until, uses_per_patron, and discount_percent are left unexplained, and the null-vs-unset distinction is only addressed for the two caps.

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 opens with a specific verb+resource ('Patch a coupon's editable fields'), which cleanly separates it from siblings like mint_coupon, delete_coupon, and list_coupons. It stops short of naming those alternatives explicitly, but the operation is unambiguous.

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?

It gives operational guidance ('Pass only the fields you want to change') and a precondition ('RESTRICTED to operator — requires proof'), which orients the caller. However, it never states when to prefer this over siblings such as mint_coupon or redeeming/forgetting a coupon, leaving the use/avoid decision largely implied.

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