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

Annotations declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the tool is safe and non-mutating. The description adds significant behavioral context beyond annotations: it details the exact formula and its components (e.g., base units per year, caps at 45 or 50 units), the applicability condition (insurance years before 1998), and a disclaimer that results are for reference only. This fully informs the agent of the tool's behavior and limitations.

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 consists of two sentences: the first conveys the core purpose and formula, the second provides a disclaimer. It is front-loaded with essential information. While the first sentence is somewhat long, it is still clear. There is no unnecessary verbosity, and 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 that the tool has an output schema (not shown but indicated), annotations, and full parameter coverage, the description is fairly complete. It explains the formula, applicability, and provides a disclaimer. The only minor gap is the lack of mention about rounding or precision of the result, but this is acceptable.

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% with descriptions for all 6 parameters. The description adds overarching context by explaining how parameters map to the formula (e.g., preSixtyYears and postSixtyYears correspond to years before/after age 60). However, most parameter details (e.g., the 5-year cap on postSixtyYears) are already in the schema descriptions. The description does not provide substantial new meaning beyond what the schema already conveys.

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 calculates the old-age single payment using a specific formula ('基數制'), including the formula details. The name and title are in Chinese and match the description. It distinguishes from siblings like calculate_old_age_lump_sum by specifying the exact type of lump-sum calculation and its applicability to those with insurance years before 1998.

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 mentions it is applicable for those with insurance years before 1998 ('適用 98 年前已有保險年資者'), providing a clear context. However, it does not explicitly state when not to use this tool or suggest alternative tools (e.g., calculate_old_age_pension for those with newer insurance years). The disclaimer about reference only is present but does not guide selection.

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