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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint, so the safety profile is covered by structured data. The description adds the GET /customers endpoint and the filterable axes, but discloses nothing about pagination behavior, result volume, auth requirements, or rate limits beyond what the schema/annotations 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 compact sentences: the resource and returned fields first, then the filter capabilities, then the endpoint. No filler, well front-loaded. The field enumeration is dense but each item carries selection value.

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, zero-required-parameter list endpoint with no output schema, the description is adequately complete: it enumerates the returned fields (compensating for the missing output schema) and covers all filter axes. It stops short of pagination/result-size guidance, which the schema party covers via page/per_page.

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 explains every parameter (page, sort, filter, metadata, per_page, open_balance, updated_after, payment_source). The description's filter list maps to a subset of these but adds no syntax, format, or constraint detail beyond the schema; 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+resource ('List customers (accounts receivable debtors)') and enumerates the fields returned (name, number, email, payment terms, currency, autopay/chasing settings, owner). Combined with the sibling set (invoiced_get_customer, invoiced_create_customer), an agent can immediately tell this is the collection-enumeration tool rather than a single-record fetch or a write.

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 names the available filter dimensions ('open balance, saved payment method, update time or any exact-match column'), which implies when the tool is useful, but never states when to prefer it over invoiced_get_customer or how it relates to the other list_* tools. Usage is implied rather than asserted, and there are no exclusions.

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