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

No annotations are provided, so the description carries the full burden. It implies a read-only retrieval and discloses the returned payload shape (positions, payments), which is valuable, but says nothing about permissions, error behavior for unknown IDs, or whether related nested data can be large/truncated.

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 sentences plus an enumerated value list, all front-loaded with the action and return contents. Slightly dense, but every clause (return shape, use case, allowed document types) earns its place.

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 simple 2-parameter read tool with no output schema, the description adequately covers what the call returns and the valid type values. Missing only failure/handling notes, which limits it below a 5.

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 coverage is 100%, so baseline would be 3. The description adds real value by enumerating the valid document_type values (supplier_invoice default, supplier_order, supplier_proforma_invoice, supplier_fiscal_receipt, simplified_supplier_invoice), which the schema does not constrain via enum.

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?

Specific verb+resource ('Get a single supplier document by ID') plus an explicit statement of what is returned (line items/positions and payments). This clearly distinguishes it from the sibling search_* and list_* tools, which retrieve collections rather than one document.

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 concrete use case: reading an invoice's positions before copying them to another document type, with a conversion example. It does not explicitly say when NOT to use it (e.g. use search_supplier_invoices for browsing), but the retrieval-by-ID framing makes the boundary clear.

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