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

readOnlyHint=true already covers the safety profile, and the description adds genuinely useful behavior: version-order sorting, the returned field set, and the pagination stop rule. It stops short of describing page-size defaults or what version numbers mean, but the essentials for correct iterative calls are present.

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 short sentences, no filler: purpose and field list first, then the alternative route, then the pagination rule. Every clause carries operational 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?

With no output schema, the description compensates by enumerating returned fields and explaining the cursor flow, which is what an agent needs to consume results. It could say more about the shape of the response envelope (where next_after lives), but nothing critical is missing.

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 after/before/deleted/page_size are already fully documented in the schema. The description's mention of version ordering and next_after adds only marginal framing beyond what the parameters already say.

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), names the exact fields returned, and distinguishes itself from search_customers by scope. An agent can identify it against siblings like get_customer or search_customers without opening a schema.

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?

Explicitly routes name/email lookups to search_customers and gives the pagination loop plus termination condition ('stop when data is empty'). The only gap is that it says 'next_after' while the input parameter is named 'after', but the schema description reconciles this.

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