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

With no annotations, the description carries the full burden. It does disclose the return content (header, line items, label count, surcharges), which substitutes for a missing output schema and implies a read-only operation, but it says nothing about permissions, rate limits, or side effects.

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 dense sentence that front-loads the keying parameter and lists returns compactly, with no filler. The fragment style is telegraphic but every clause carries information.

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?

The description usefully covers the return payload in the absence of an output schema, but with no annotations it omits behavioral context such as safety, permissions, and how it relates to the sibling FindInvoice. Adequate but with clear gaps.

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 parameters are already documented (invoiceNumber as customer invoice number, intentId from RecordUserQuestion). The description adds no format or edge-case detail beyond 'by invoice number', 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 resource (invoice) and enumerates the payload it returns — header, line items, label count in period, related surcharges — which is more than a restated name. It does not explicitly differentiate itself from the sibling FindInvoice, leaving the agent to infer 'deep-dive' vs simple lookup.

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 phrase 'deep-dive by invoice number' implies a fuller investigation than a plain lookup, which hints at when to prefer it over FindInvoice, but no alternative is named and no when-not conditions are given.

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