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 discloses the return format (filename, csv_utf8, csv_shift_jis_base64) and the requirement to use Shift_JIS for import. It also states 'Owner-only,' indicating access control. It does not mention any side effects (e.g., marking orders as shipped), but given the tool generates a CSV without modifying state, this is acceptable.

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 concise with no wasted words. It front-loads the core action ('Generate a 送り状 CSV for all un-shipped orders'), then efficiently covers the format, prerequisites, and return structure. Every sentence adds value.

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 the simple input (one optional parameter) and no output schema, the description fully covers what the tool does, its return value, and important context (owner-only, first-time registration). No gaps remain for effective agent invocation.

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% for the single 'courier' parameter with an enum and description. The tool description adds context by naming the specific courier systems (ヤマト B2クラウド and 佐川 e飛伝) beyond the schema's brief description, but this is incremental. Baseline 3 is appropriate.

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 title and description clearly state the tool generates a shipping-label CSV for un-shipped orders for two specific couriers. It distinguishes itself from sibling shipping tools (e.g., mu_ship_import_tracking, mu_ship_mark, mu_ship_order) by focusing on CSV generation.

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 explicitly states the CSV is for all un-shipped orders, specifies the two courier formats, and notes that no carrier API/contract is needed. It also advises first-time registration of the column layout. However, it does not explicitly mention when not to use this tool or provide alternative tools for other scenarios.

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