UK Data for Agents

calculate_investment_return

Read-onlyIdempotent

Calculates the return on investment using compound interest formula. Returns the final amount and total return given an initial deposit, annual interest rate (as a percentage), and investment period in years. (cost: 1 credit)

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "calculate_investment_return"
  }
}

Input Schema

Name	Required	Description
`num_years`	No	number, required, investment period in years
`interest_rate`	No	number, required, annual interest rate as a percentage (e.g., 5 for 5%)
`initial_amount`	No	number, required, initial deposit or principal amount in currency units

Schema Changelog

Changes observed during successful MCP inspections.

AddedNov 7, 2026

TDQS

B3.3/5.0

Behavior3/5

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

The annotations already establish that this is a read-only, idempotent, non-destructive operation. The description adds useful context by naming the compound interest formula, describing the returned final amount and total return, and stating a 1-credit cost. It does not disclose compounding frequency or other assumptions, so it adds some but not rich behavioral detail.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two short sentences plus a parenthetical cost note. It front-loads the purpose, then states outputs and inputs with no unnecessary wording.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool is simple and the schema plus annotations cover most structured details. However, for an agent choosing among many similar investment and interest calculators, the description lacks sibling differentiation and does not specify the compounding assumption, leaving meaningful ambiguity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, and the schema already defines the initial deposit, annual interest rate as a percentage, and investment period in years. The description restates those meanings without adding format, constraints, or examples beyond the schema, which is the baseline for fully documented parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description gives a specific verb and resource: calculates return on investment using the compound interest formula. It also states the returned values and the inputs. It does not distinguish itself from similar sibling tools such as compound_interest, future_investment_value, or project_investment_growth, so it is clear but lacks sibling differentiation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no explicit when-to-use guidance, no exclusions, and no alternatives. The presence of similar compound-interest and investment-growth siblings makes routing ambiguous, and the description only implies usage through its listed inputs.

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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