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

With no output schema, the description carries the return-value burden and does so well: it discloses totals per currency and VAT rate, data-quality warnings (net + VAT mismatch), and a 24-hour download link expiry. It also states a hard capacity limit of 200 receipts per call, information not derivable from the annotations.

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?

Three dense sentences: capability first, then what comes back including the warning and link expiry, then the capacity limit. Every clause carries operational information with no filler.

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 file-generation tool with five parameters, 100% schema coverage and no output schema, the description covers output contents, validity window and limits. The only minor gap is not clarifying whether earlier generated files remain accessible or how errors on invalid receipt data are surfaced.

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 parameter meaning is already fully documented; the description adds only the VAT-per-column output behavior and the 200-receipt cap (which mirrors the schema's maxItems). Baseline 3 is appropriate given the schema does the heavy lifting.

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 and artifact ('turn receipts ... into an Excel, CSV, Xero or QuickBooks import file') and adds concrete processing detail (VAT split per rate). It clearly distinguishes the tool from scan_receipts_on_website (reading receipts) and convert_currency (a separate conversion step), since it consumes already-read receipts.

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 'receipts you have read' establishes the precondition that receipts must already be extracted, which implicitly routes the agent to VAD/scan-style tools first. It does not explicitly name siblings or state when not to use it, but the context for use is clear.

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