mcp-india-stack

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calculate_ppf_maturity

Read-onlyIdempotent

Calculate PPF maturity amount with a year-by-year breakdown to plan long-term savings, compare investment options, or estimate retirement corpus.

Instructions

Calculate PPF maturity amount with year-by-year breakdown.

Use when planning long-term savings, comparing investment options, or calculating retirement corpus.

Args: annual_investment: Amount invested per year (max ₹1,50,000). tenure_years: PPF tenure (15, 20, 25, or 30 years). annual_interest_rate: PPF rate (default 7.1% for FY2025-26).

Returns: Standard envelope with maturity amount, total invested, interest earned.

Notes: EEE tax status: exempt at investment, accumulation, and maturity. Rate is government-administered and revised quarterly.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "annual_investment": "<annual_investment>"
    },
    "name": "calculate_ppf_maturity"
  }
}

Input Schema

Name	Required	Description	Default
`tenure_years`	No	PPF tenure in years (15, 20, 25, or 30)
`financial_year`	No	Financial year (e.g. '2025-26', '2026-27')	2025-26
`annual_investment`	Yes	Amount invested per year in INR
`annual_interest_rate`	No	Annual interest rate percentage (default 7.1 for FY2025-26)

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.8.0Nov 5, 2026

addedInput schema / properties / financial_year

Added value: +{
+  "default": "2025-26",
+  "description": "Financial year (e.g. '2025-26', '2026-27')",
+  "title": "Financial Year",
+  "type": "string"
+}

Changed6 schema fields changedv0.5.0Aug 25, 2026
- removedInput schema / additionalProperties
```
Removed value: -false
```
- addedInput schema / properties / annual_interest_rate / title
```
Added value: +"Annual Interest Rate"
```
- addedInput schema / properties / annual_investment / title
```
Added value: +"Annual Investment"
```
- addedInput schema / properties / tenure_years / title
```
Added value: +"Tenure Years"
```
- addedInput schema / title
```
Added value: +"calculate_ppf_maturityArguments"
```
- addedOutput schema / title
```
Added value: +"calculate_ppf_maturityDictOutput"
```
Addedv0.4.2Jun 8, 2026

TDQS

A3.7/5.0

Behavior4/5

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

Annotations already establish readOnly, idempotent, closed-world behavior, so the description's job is to add domain context — and it does: EEE tax treatment, the ₹1,50,000 annual cap, and the warning that the rate is government-administered and revised quarterly. That last note is genuinely useful because it implies results are rate-sensitive and time-bound. It doesn't add much beyond that (no note on compounding convention or rounding), keeping it out of 5 territory.

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

Conciseness4/5

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

Well front-loaded: purpose first, then usage, then structured Args/Returns/Notes blocks that are easy to scan. There is mild redundancy — the 7.1% default is restated from the schema and the Returns block duplicates an existing output schema — but nothing is verbose enough to obstruct the reader.

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

Completeness4/5

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

For a read-only calculator with a full output schema and 100% schema coverage, the description covers the domain caveats an agent needs: tax status, contribution cap, and rate volatility. The one gap is that financial_year's effect is never explained despite the note that rates are revised quarterly, leaving the agent unsure how that parameter changes the result.

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 coverage is 100%, so the baseline is 3. The description does add one meaningful constraint not present in the schema — the ₹1,50,000 maximum on annual_investment — but it leaves the financial_year parameter completely unmentioned and simply restates the tenure options and default rate that the schema already documents.

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 first sentence gives a specific verb and resource (calculate PPF maturity amount) plus the output shape (year-by-year breakdown), which clearly separates it from sibling calculators like calculate_fd_maturity, calculate_rd_maturity, and calculate_sukanya_samriddhi. It stops short of naming those alternatives explicitly, so it lands at 4 rather than 5.

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

Usage Guidelines3/5

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

The 'Use when planning long-term savings, comparing investment options, or calculating retirement corpus' line gives real usage context, which is more than nothing. But it offers no when-not guidance and never routes the agent to a sibling for non-PPF instruments, so an agent comparing FD vs PPF gets no disambiguation help.

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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