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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the underlying API mapping (GET /customers with filter[store_id], filter[email]), which helps an agent reason about the call, but says nothing about pagination behavior, rate limits, or result ordering.

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?

One sentence plus a compact API mapping line, front-loaded with the core action and filtering scope. No wasted prose, though the parenthetical endpoint detail is somewhat redundant for an agent already given structured params.

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 5-parameter, all-optional list tool with no output schema, the description covers filtering but not the shape or pagination envelope of the returned customer list. Functional but incomplete on the return side, which no output schema compensates for.

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 every parameter (email, include, store_id, page_size, page_number) is already documented in the schema; baseline is 3. The description's mention of the API filter syntax adds marginal mapping value but no semantics beyond the schema.

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 customers') and immediately scopes it as optionally filtered by store and/or email. It is distinguishable from get_customer by the list verb, though it does not explicitly name that sibling as the alternative.

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 description implies usage (fetch customers with optional store/email filters) but never states when to use this versus lemonsqueezy_get_customer or the other list_* tools, nor any prerequisites. Adequate but no explicit routing guidance.

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