mf_update_billing

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

With no annotations provided, the description carries the full burden of behavioral disclosure. '更新します' (updates) implies a mutation operation, but the description doesn't specify required permissions, whether updates are partial or full, what happens to unspecified fields, or any side effects. The items parameter description hints at '全置換' (full replacement), but this is buried in the schema, not the tool description.

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 extremely concise - a single Japanese sentence. It's front-loaded with the core action. However, for a complex mutation tool with 11 parameters, this brevity borders on under-specification rather than optimal conciseness.

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 mutation tool with 11 parameters, no annotations, and no output schema, the description is incomplete. It doesn't explain what 'updating' entails operationally, what permissions are needed, how errors are handled, or what the response contains. The agent must rely entirely on the input schema without contextual guidance.

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 all parameters well-documented in Japanese. The tool description adds no additional parameter information beyond what's in the schema. According to guidelines, when schema coverage is high (>80%), the baseline score is 3 even with no param info in the description.

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 '請求書を更新します' (Updates an invoice) states a clear verb ('更新します' - updates) and resource ('請求書' - invoice), providing basic purpose. However, it doesn't distinguish this from sibling tools like mf_update_payment_status or mf_update_quote, nor does it specify what aspects of an invoice can be updated beyond the generic term.

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. There are no explicit instructions on prerequisites (e.g., needing an existing billing_id), when to choose this over mf_create_billing, or how it differs from mf_update_payment_status. The agent must infer usage from the tool name and parameters alone.

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