Update invoice draft

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

Without annotations, the description carries the full burden for behavioral disclosure. It only says 'Update an existing draft invoice', which barely restates the tool name. There is no mention of whether the update is partial or full replacement, what happens to unspecified fields, or any side effects. This is a tautology of the title.

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?

The description is concise and free of fluff, but it is arguably too terse for the tool's complexity. It is a single sentence that sacrifices useful specifics. It earns a middle score for being short and clear, yet under-specified relative to the 9-parameter schema.

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 9 parameters, no annotations, and no output schema, this one-sentence description is severely incomplete. It does not explain required fields (beyond the schema), update semantics, return values, or any edge cases. The agent would have to rely entirely on the schema and guess significant behavioral aspects.

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 description adds no meaning to the parameters. While five of nine properties have schema descriptions, the remaining four (layoutNumber, recipientName, paymentTermsNumber, recipientVatZoneNumber) lack any explanation, and the description does not compensate for these gaps or clarify how the nested 'lines' array behaves during an update.

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 clearly states the action ('Update') and the resource ('existing draft invoice'), which distinguishes it from sibling tools like create_invoice_draft (new) and book_invoice_draft (booking). The word 'existing' is a specific differentiator.

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?

No guidance is provided on when to use this tool versus alternatives. It does not mention that it should be used for modifying an already-created draft, nor does it reference create_invoice_draft for new drafts. The only hint is 'existing', but no explicit usage context or exclusions are given.

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