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

Annotations already declare readOnlyHint=false / idempotentHint=false / destructiveHint=true, so the write nature is covered. The description adds real value on top: the result is a draft with no number, it is not sent, and completion happens later in Billomat — useful lifecycle context for an agent deciding whether this call alone finishes the job.

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 tight sentences with the 'WRITE:' marker and the draft-state constraint front-loaded. No filler, though it is slightly dense in the second sentence.

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 an 11-parameter creation tool with only one required field, full schema coverage, and no output schema, the description covers purpose and outcome adequately. Minor gaps: no mention of auth/permission needs or what the response returns, but these are not strictly required here.

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 one of the 11 parameters (client_id, items, net_gross, validity_days, etc.) is already documented in the schema. The description only adds 'with optional line items', which is already implied, so the schema does the heavy lifting — 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 and resource ('create an offer (Angebot) as a DRAFT') plus the optional line-item scope, so it is clearly distinguishable from list_offers/get_offer and from create_draft_invoice. It stops short of naming a sibling explicitly, but the resource and draft state are unambiguous.

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?

Provides clear context for when this is appropriate: it produces an incomplete, unnumbered, unsent draft that should be reviewed and completed in Billomat. It does not name an alternative or spell out when NOT to use it, so it falls just short of explicit routing guidance.

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