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

Goes well beyond the single destructiveHint annotation: it discloses that a draft has no number, that issuing consumes the next number of the series, that issuing cannot be undone from the API, that the document may be transmitted to e-Factura / ANAF, and the notable negative side effect that stock is NOT discharged. These are exactly the consequences an agent needs before mutating state.

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?

Front-loads the purpose, then the draft/issue consequence, then the stock caveat, closing with the endpoint token. Dense but nearly every clause carries information; the trailing 'POST /invoice/v2 (useEstimateDetails)' is implementation detail of marginal value to an agent already given a tool.

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 5-parameter mutation with no output schema and only a destructiveHint annotation, the description covers the critical side effects and irreversibility. It does not describe what is returned on success (e.g. the assigned number/series), which would help the agent confirm issuing behavior, and it omits sibling differentiation against smartbill_create_invoice.

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 every parameter including the draft/today defaults and min/max lengths is already documented in the schema. The description adds the source-copy behavior but no parameter-level detail beyond it, 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 verb+resource+source: 'Create an invoice from an existing proforma (client and lines are copied from it)'. The parenthetical clarifies the copy semantics, which differentiates it from the sibling smartbill_create_invoice that presumably starts from scratch.

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?

Gives a clear conditional for the draft flag ('Default is a DRAFT; with draft=false the invoice is ISSUED...'), and the schema reinforces the 'pass false ONLY when the user explicitly wants it ISSUED now' rule. However, the description never states when to choose this tool over smartbill_create_invoice, so the alternative-selection guidance is left implicit.

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