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

Annotations already declare readOnlyHint=true, so the safety profile is covered and the description only needs to add context. It adds that these are 'reusable' items composed of the listed attributes, but says nothing about result volume, default page size of 25, or ordering beyond what the schema states.

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?

The description is a single short clause with no filler, but its brevity comes at the cost of clarity: without a verb it reads as a restatement of the schema's field list rather than a front-loaded statement of what the call returns.

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 simple read-only list tool with zero required parameters and a fully described schema, the minimum an agent needs is present, and the field list hints at the returned shape. However, with no output schema and no note that the response is paginated or a list, the description is only just sufficient.

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%, with page, pageSize, and the filter query syntax fully documented in the schema, including the && filter grammar and example. The description adds no parameter meaning beyond that, 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?

The description is a noun fragment listing item fields (description, product type, unit price, tax rate, bookkeeping account) rather than a verb+resource statement; only the title and tool name convey that this lists reusable invoice items. The resource ('items') is distinguishable from siblings like bokio_list_customers or bokio_list_invoices, but the agent must infer the retrieval action.

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?

There is no statement of when to use this tool, no prerequisites, and no mention of alternatives (e.g., using items when creating an invoice draft vs. listing existing ones). The description offers no routing guidance at all.

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