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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered; the description goes further by explaining the data flow ('details travel in the link itself and are not stored by TapTax') and the human-in-the-loop step. It does not mention validation failures or limits, but the added privacy/no-persistence context is genuinely useful.

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 sentences, front-loaded with the document types before the behavioral detail, with no filler. Slightly longer than needed but every sentence 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?

With no output schema, the description correctly fills that gap by describing the return ('the totals and a link') and the downstream workflow. Combined with read-only annotations it is nearly complete, though the sparse parameter documentation leaves the input side thin.

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 only 46% across 13 parameters, so the description is expected to compensate. It merely echoes the kind enum (invoice/quote/receipt/credit note/pro forma) and says nothing about lines, VAT rate, date, template, or the client/from fields, so the under-documented half stays undocumented.

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 concrete verb (Prepare) and the exact resource set (invoice, quote, receipt, credit note, pro forma invoice), and pins the channel ('TapTax's free document generator, without a TapTax account'). That framing distinguishes it from account-bound siblings like create_invoice and send_invoice without needing their schemas.

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 'without a TapTax account' and 'opens the generator... downloads the PDF' framing implies the intended scenario, so usage is inferable. However, it never names an alternative (create_invoice, send_invoice) or states when-not to use this tool, leaving the agent to guess between the document-producing siblings.

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