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

Annotations already cover readOnly, idempotent, non-destructive and closed-world, so the description correctly spends its words elsewhere: the connect/auth requirement, newest-first ordering, and the archived-exclusion rule that a caller could not infer otherwise. It does not describe pagination or what happens when more results exist than the limit allows.

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 tight sentences with no filler, led by the eligibility/auth constraint before the payload description. The parenthetical "(asks them to connect)" is slightly awkward but still information-bearing rather than padding.

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?

With no output schema, the description usefully enumerates the returned fields and ordering, and it documents the auth gate and archived behavior. The gap is filter and page-size semantics for the three optional parameters, which an agent needs to use them 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 0%, so the description carries the full burden and largely fails: it never says that `client` filters by client name, that `status` narrows results, or that `limit` caps page size (default 20, max 50). Listing the status values only echoes the enum already in the schema, and "client" appears as an output field, which may mislead an agent about the parameter.

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 the connected creator's invoices) and immediately enumerates the returned fields and sort order, so an agent knows exactly what it gets. It also distinguishes itself from get_invoice by explaining that archived invoices are excluded from this list but still readable individually.

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?

"Creators only, on their own Piku account (asks them to connect)" gives a clear precondition, and the closing clause routes single-invoice lookups to get_invoice. It stops short of explaining when the client/status/limit filters should be applied, so it is clear context rather than full when/when-not guidance.

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