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

With no annotations provided, the description carries the transparency burden. It does disclose the return format (structured rows with description, quantity, unit price, total), which is useful. However, it does not mention any behavioral details like required permissions, error conditions, or what happens if the invoice lacks tables, leaving transparency only partially addressed.

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 two sentences long, with the main action stated first and the output format following immediately. Every word earns its place; there is no redundancy or irrelevant detail.

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 tool with only two parameters and no output schema, the description provides essential context: it names the extracted data and the exact fields returned. It could benefit from a brief note about when to use it relative to sibling tools, but given the low complexity, it is largely complete.

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%, with both pdf_path and pdf_base64 clearly explained in the schema. The description itself does not add parameter-level detail beyond the schema, so it meets but does not exceed the baseline for high schema coverage.

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 uses a specific verb ('Extract') and names the resource ('tables and line items from invoice'), clearly distinguishing this tool from siblings like invoice_extract or invoice_ocr. It also states the output as structured rows with particular fields, reinforcing the tool's unique purpose.

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?

The description implies use for extracting table/line-item data from invoices, but it does not explicitly state when to choose this tool over alternatives such as invoice_extract or invoice_validate. There are no exclusions or direct sibling comparisons, though the specialized wording gives some contextual guidance.

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