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

Annotations declare readOnlyHint=true, so safety is covered. The description still adds meaningful behavior beyond that: result ordering ('newest first'), cursor-based pagination with the specific metadata.next_cursor field, and the fact that email is an exact-match lookup. It omits rate limits and the default page size, but the added context is solid.

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 what is returned and how it is ordered, then how to filter, then pagination. Every clause carries information; nothing is redundant with the title.

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 6-param list tool with no output schema, the description covers the essentials: returned fields, ordering, filter modes and pagination continuation. It leaves include_vip_status and the 1-250 limit default to the schema, which is acceptable, so it is nearly but not fully self-contained.

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%, so the schema already documents email, limit, state, cursor, updated_at_min and include_vip_status. The description reinforces filtering semantics (exact email, state, last-updated) but adds no syntax or format detail beyond the schema, 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?

States a specific verb and resource ('List loyalty-program customers'), plus scope details like ordering ('newest first') and returned fields (points balance, state, VIP tier id). It is clearly distinct from the write/list siblings, but does not mention smile_get_customer, which is the natural alternative for a single-record fetch.

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?

Gives concrete selection conditions: look up by exact email, or filter by state or last-updated time. That is clear usage context, but it never states when NOT to use this tool or routes the agent to smile_get_customer for single-customer reads, nor flags that email lookup is exact-match only (no fuzzy search).

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