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

Goes well beyond the annotations by disclosing the two-phase propose-then-issue flow with seller approval, that the PDF is attached to the order, the idempotency-style refusal when already invoiced, and the currency/environment constraints. This is exactly the extra behavioral context annotations cannot convey.

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, all of which carry information: the propose flow, the refusal condition, and the environment/currency limits. Front-loaded with the action, though the closing 'Works on:' fragment is slightly terse.

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 write tool with an output schema already present, the description covers everything an agent needs: what gets derived from the order, the simulated-first/approval lifecycle, refusal conditions, and environment scope. Return values are correctly left to the output schema.

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 the schema already documents all six parameters. The description adds a useful implicit clarification that buyer/products/shipping/vouchers are pulled from the order and must not be retyped (consistent with additionalProperties=false), but provides no parameter-level detail beyond that. 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 (Propose) and resource (the invoice for one marketplace order), and the bracketed tag [Invoicing changes] plus the order-linked framing distinguishes it from the sibling invoices_issue and orders_attach_invoice. An agent can tell what it does without opening the schema.

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 clear eligibility and refusal conditions: refused if the order is already invoiced, RON-only (eMAG/Trendyol Romania), and Demo invoicing environment. However, it never names an alternative sibling (e.g. invoices_issue for non-order invoicing) or states when to prefer this over those, so it stops short of explicit routing.

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