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

With no annotations provided, the description carries the burden of behavioral disclosure. It reveals the data scope (signed-in customer only), the returned content (totals, balances, signed PDF links), and the required authentication context (portal personal token). It does not mention pagination or rate limits, but for a list operation, the disclosed behavior is reasonably complete.

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?

A single, well-structured sentence front-loads the core action and resource, lists the key output details, and ends with the necessary prerequisite and cross-reference. Every word adds value; no filler or repetition.

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 parameterless list tool, the description covers the essential context: what it returns, for whom, and what authentication is needed. The pointer to my-orders for the token completes the operational loop. There is no output schema, so the explicit mention of totals, balances, and signed PDF links effectively communicates return contents.

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?

The input schema defines zero parameters, and the rubric sets a baseline of 4 for this case. The description adds no parameter information because there are none; the existing text aligns with the schema's emptiness without contradiction.

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 states a specific verb ('List'), a precise resource ('the signed-in customer's own Zoho invoices'), and the key fields included (totals, balances, signed PDF links). The scope is unambiguous and notably distinct from any sibling: no other tool mentions invoices, and the 'own' qualifier clarifies the data boundary.

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 gives clear context: it lists the signed-in customer's invoices and explicitly states the prerequisite ('Requires the portal personal token') with a pointer to a sibling tool ('see my-orders'). It does not explicitly state when not to use it or list alternatives, but none of the siblings are invoice-related, making the usage context sufficiently clear.

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