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

Annotations already declare readOnlyHint=true, so safety is covered; the description adds that results include usage and validity data and are paginated, plus the admin API surface, which is useful context. It doesn't disclose admin permission requirements, default/max page behavior beyond the schema, or ordering of results, so it adds moderate value only.

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?

Two short sentences, no repetition, resource and scope front-loaded followed by the API endpoint as supporting reference. Every clause carries information.

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 zero-required-parameter read-only list with fully documented params and no output schema, the description covers what the tool returns at a high level, paging behavior, and the admin endpoint. Only the shape of returned fields and search matching semantics are left implicit, which is a minor gap.

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% — page, size, and search are all documented in the schema, including defaults and max. The description's 'with paging' merely echoes the schema and it says nothing about what 'search' matches against, 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 and resource ('List discount codes') and adds scope detail ('with usage and validity, with paging'), which tells the agent what data comes back. Siblings are all distinct resources, so no explicit differentiation is required, but it stops short of a 5 because it doesn't distinguish this list from any filtered variant.

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 'Admin API: GET /v1/admin/discount-codes' note implies this is an admin-scoped read and the paging hint suggests the iterative listing pattern, but there is no explicit when-to-use or when-not-to-use guidance or named alternative. Usage is inferable rather than stated.

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