mf_download_billing_pdf

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the action (get PDF URL) but doesn't describe traits like whether this is a read-only operation, if it requires authentication, rate limits, error conditions, or the format of the returned URL. For a tool with no annotation coverage, this is a significant gap in transparency.

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 a single, efficient sentence in Japanese that directly states the tool's purpose without unnecessary words. It's appropriately sized and front-loaded, with zero waste, making it easy to parse quickly.

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?

Given no annotations, no output schema, and a simple input schema, the description is incomplete. It lacks details on behavioral traits (e.g., safety, authentication), output format, or error handling. For a tool that retrieves URLs, more context on what the URL represents (e.g., temporary, downloadable) would be helpful, but it's missing.

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?

The input schema has 100% description coverage (billing_id is documented as '請求書ID' meaning 'invoice ID'), so the baseline is 3. The description doesn't add any parameter-specific details beyond what the schema provides, such as format examples or constraints. It compensates minimally by implying the parameter is needed but doesn't enhance semantics.

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 clearly states the tool's purpose: '請求書のPDF URLを取得します' translates to 'Get the PDF URL of an invoice.' This specifies the verb (get/retrieve) and resource (invoice PDF URL). It distinguishes from siblings like mf_get_billing (which likely returns billing data) and mf_download_quote_pdf (which handles quotes), but doesn't explicitly differentiate from other PDF-related tools beyond the resource type.

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing a valid billing_id), exclusions, or comparisons to siblings like mf_get_billing (which might return metadata) or mf_list_billings (for listing). Usage is implied by the purpose but lacks explicit context.

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