get_invoice_data

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds useful context that the response contains the actual invoice content and can optionally carry the PDF, but says nothing about failure behavior for a missing invoice or about the size/latency cost of includePdf.

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, front-loaded with the resource and the identifying key, with no filler. The trailing PDF clause mildly duplicates what the schema's includePdf already states, but costs only a few words.

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 tool with full schema coverage, no output schema and complete annotations, the description is mostly sufficient. The notable gap is that the existence of the sibling get_invoice_pdf makes the description's optional-PDF behavior ambiguous: it never tells the agent which of the two to use for retrieving a PDF.

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%: company, includePdf and invoiceNumber are each documented with defaults and an example in the schema. The description's "Optionally the PDF too" merely restates the includePdf parameter and adds no new semantics or format detail.

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 names a specific resource and lookup key ("outgoing invoice by invoice number") and enumerates the returned content (seller, buyer, items, totals, amount paid, outstanding), so an agent knows exactly what it fetches. It does not, however, distinguish itself from the sibling get_invoice_pdf or list_invoices.

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?

Usage is only implied: "by invoice number" plus "Optionally the PDF too" suggests single-invoice retrieval with optional attachment. There is no explicit when-to-use guidance, no mention of when to prefer get_invoice_pdf or list_invoices, and no statement of what happens with an invalid or unknown number.

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