present_value_annuity

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. It only states what the tool calculates but provides no information about how it behaves: no error conditions, no precision information, no assumptions about payment timing (beginning vs end of period), no mention of what happens with negative inputs, and no details about the return format. For a financial calculation tool with zero annotation coverage, this is inadequate.

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 Chinese phrase that directly states the tool's purpose. There's no wasted language or unnecessary elaboration. It's front-loaded with the essential information, though that information is minimal.

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 financial calculation tool with 3 parameters, 0% schema description coverage, no annotations, and no output schema, the description is insufficient. It doesn't explain what the tool returns, doesn't clarify parameter meanings, doesn't provide usage context, and doesn't disclose behavioral characteristics. The description leaves too many gaps for effective tool use.

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 schema description coverage is 0%, meaning none of the three parameters have descriptions in the schema. The tool description provides no parameter information whatsoever - it doesn't mention what 'payment', 'periods', or 'interest_rate' represent, their units, valid ranges beyond the schema's technical constraints, or how they relate to the calculation. The description fails to compensate for the complete lack of schema documentation.

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: '计算普通年金的现值' (calculates the present value of an ordinary annuity). It specifies the verb (calculate) and resource (present value of ordinary annuity), which is clear and specific. However, it doesn't explicitly distinguish from its sibling 'future_value_annuity', which is a closely related financial calculation tool.

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's no mention of when this calculation is appropriate, what financial scenarios it applies to, or how it differs from related tools like 'future_value_annuity' or 'net_present_value'. The user must infer usage from the tool name alone.

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