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

The readOnlyHint annotation already establishes this as a safe read, so the bar is lower. The description adds the filterable scope but says nothing beyond annotations about pagination behavior, ordering defaults, or response shape beyond what the schema details already provide.

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, front-loaded with the tool's purpose and immediately followed by filters. The trailing API route reference is minor filler but not wasteful, so it is slightly below a perfect score.

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 read-only list tool whose annotations cover the safety profile and whose schema fully documents all parameters, the description supplies enough to call it correctly. No output schema exists, but a list of customers needs little return-value explanation, so coverage is nearly 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 100%, so the schema already documents all 8 parameters with types, ranges, and patterns. The description's mention of code/name-prefix, currency, and date filters only restates what the schema carries, meeting the baseline 3 without adding syntax or format detail.

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 (List) and resource (customers) plus its filter capabilities, clearly distinct from siblings like unleashed_get_customer (single) and unleashed_create_customer (write). It does not explicitly name an alternative, so it stops short of a 5.

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 phrase 'optionally filtered by...' implies the retrieval use case, but there is no explicit when-to-use guidance, no conditions for choosing this over list_products or a get_ variant, and no exclusions. Usage is implied rather than stated.

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