Compound interest calculator client and server side from freedailypro
| Name | Required | Description | Default |
|---|---|---|---|
| years | Yes | ||
| frequency | No | ||
| principal | Yes | ||
| startDate | No | Optional start date, as YYYY-MM-DD. Adds startDate and maturityDate (the date the future value is reached). It only labels the timeline; the amounts do not change. | |
| annualRatePercent | Yes |
Changes observed during successful MCP inspections.
Input schema / properties / startDateAdded value: +{
+ "description": "Optional start date, as YYYY-MM-DD. Adds startDate and maturityDate (the date the future value is reached). It only labels the timeline; the amounts do not change.",
+ "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
+ "type": "string"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description adds nothing beyond that — no note on what is computed, whether frequency defaults are applied, or what the response contains; "client and server side from freedailypro" is meaningless to an agent.
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?
It is short, but the brevity is under-specification rather than economy: the single clause is a tautology of the title plus a vendor tagline that occupies the only sentence available for useful content.
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?
With 5 parameters, 3 required, 20% schema coverage, and no output schema, the description needs to carry real weight. It doesn't say what value is returned (future value only, or also total interest/contributions), how frequency affects the math, or what startDate/maturityDate do — leaving an agent unable to predict the result.
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 only 20% (just startDate), and the description supplies no parameter meaning at all. Critical gaps go unaddressed: whether 'frequency' is optional and what its default is, that 'years' must be 0-100, and whether annualRatePercent is a percentage (e.g. 5 vs 0.05).
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 essentially restates the tool name ("Compound interest calculator") and adds only vendor noise ("client and server side from freedailypro"). It gives no scope or output framing that would distinguish it from the many sibling calculators such as calculate_simple_interest, calculate_sip, or calculate_loan.
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?
There is no statement of when to use this tool, when not to, or which sibling calculator to prefer for a given financial scenario. The only usage signal comes from the tool name itself.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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