Amaltash Investment & Retirement Calculators

Stock Return and DCA Calculator

replay_past_investing

Read-onlyIdempotent

Stock return and dollar-cost averaging (DCA) calculator with an interactive chart. Shows what investing in a US stock or fund would have become, using real past prices, as regular deposits, a lump sum, or both. Use it for what-if-I-had-invested and DCA questions about a ticker such as AAPL or VOO, over the last 120 months or fewer. It covers the past only and gives no estimate of the future.

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": {
      "ticker": "<ticker>",
      "amount": "<amount>",
      "months_back": "<months_back>"
    },
    "name": "replay_past_investing"
  }
}

Input Schema

Name	Required	Description	Default
`amount`	Yes	Dollars invested each time. Can be 0 if there is a starting amount.
`ticker`	Yes	A US stock or fund ticker, such as AAPL or SPY.
`cadence`	No	How often the amount goes in: day, week or month. Defaults to month.	month
`months_back`	Yes	How many months before the latest data to begin, from 1 to 120.
`starting_amount`	No	Dollars invested once at the start. Defaults to 0.

Schema Changelog

Changes observed during successful MCP inspections.

First observedNov 10, 2026

TDQS

A4/5.0

Behavior4/5

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

Annotations already cover read-only, idempotent, non-destructive and closed-world behavior, so the description only needs to add context — and it does: results are based on real past prices, output is an interactive chart, the horizon is capped at 120 months, and it makes no forward-looking estimate. It does not mention failure behavior for invalid or delisted tickers.

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?

Four tight sentences with no filler: what it is, what it shows, when to use it, and the past-only limitation placed last as a caveat. Front-loaded and appropriately sized for a five-parameter calculator.

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?

With no output schema, the description carries the burden of describing results, and it does so at a high level (interactive chart of what the investment became). Combined with a fully documented input schema and safety annotations, an agent has enough to call it correctly; only the exact result shape and edge-case behavior are unstated.

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% and every parameter is already documented, so the baseline applies. The description's phrase "as regular deposits, a lump sum, or both" does clarify how amount and starting_amount can be combined, which is a modest addition beyond the schema text.

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?

States a specific verb and resource: a stock return and dollar-cost averaging calculator that shows what a historical investment in a US stock or fund would have become. It distinguishes its output (an interactive chart of past results) but never names or contrasts any sibling such as dca_vs_lump_sum, even though it explicitly supports both periodic deposits and lump sums.

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

Usage Guidelines4/5

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

Gives clear triggering contexts ("what-if-I-had-invested" and DCA questions) and a concrete example ticker, plus a scope constraint of 120 months or fewer. It does not say when to prefer a sibling like dca_vs_lump_sum or compound_interest instead, so routing guidance is incomplete.

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

All Amaltash Investment & Retirement Calculators tools Inspect

Try in Browser

One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources

Need Help?