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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds the underlying endpoints (GET /invoices/customer or /invoices/supplier), which is modest extra context, but says nothing about pagination behavior, defaults, or what the rows contain beyond four named fields.

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, front-loaded with the resource and subtype distinction, with the endpoint detail appended rather than buried. No filler, though the endpoint sentence is of limited use to an agent that does not construct HTTP calls.

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?

A read-only list tool with 6 fully documented parameters and no output schema; the description covers what is listed, both record categories, and the returned fields (date, due date, status, amount). Remaining gaps around paging and default sort are largely handled by the schema itself.

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 including enum meanings, limit bounds and offset paging advice is already documented in the schema. The description's only added semantics is restating the customer/supplier distinction at a conceptual level, 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 (list) and resource (invoices) and disambiguates the two subtypes by explaining that customer invoices are money owed to the store while supplier invoices are money the store owes. That clarifies the domain meaning of the `type` enum, though it never contrasts itself with neighboring list tools such as phppos_list_sales or phppos_list_receivings.

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 when to use it (whenever you need invoice records) and pins down the two type values, but gives no explicit when-to-use guidance, no exclusions, and no mention of alternatives in a 25-sibling toolset where list_sales/list_receivings could be confused with invoices.

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