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

With no annotations, the description carries the full burden, and it delivers a genuinely non-obvious trait: invoices from other accounts appear as absent rather than raising errors, which prevents an agent from misreading a missing record as a permission failure. It stops short of covering ordering, pagination defaults, or required scopes.

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, both load-bearing: the first frames the resource and return payload, the second front-loads the cross-account gotcha. Nothing is redundant or buried.

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 two-optional-parameter list tool with no output schema, the description covers purpose and the key visibility caveat. Only minor gaps remain, such as default limit or result ordering, which are not essential to invoking it correctly.

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 both limit and the status enum are already fully documented in the schema. The description adds no format, default, or interaction detail 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?

States a specific verb and resource ('List invoices') and adds what each result carries (status and totals). It is clearly distinguishable from the singular get_invoice and the mutating create_invoice, though it never names a sibling explicitly.

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 verb 'List' implies the browsing use case versus get_invoice for a known ID, but the description never says when to prefer one over the other or any preconditions. Usage is inferred from the name rather than stated.

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