compoundsim

app.compoundsim/compoundsimcompoundsim.appstreamable-httpv1.0.0Scanned 53 minutes ago

Compound interest and Monte Carlo simulators for investing, retirement and past asset returns.

5 tools: 1 do something that can't be undone, 3 change things and 1 only read.

Reads private data · 1
Reads text others write · 1
Can send data out · 0
2 findings

Anlyon alternative

4 of these tools change something. Run those as governed actions.

Declare what an action changes, and Anlyon puts it under a shared limit, binds every approval to the exact request, and grades the outcome. It works on any HTTPS API you can describe as an action.

Anlyon does not run, proxy or govern this MCP server. A tool your own code calls directly is not routed through Anlyon and is not governed by it.

Import an OpenAPI spec →

Tools

Grouped by what each tool does, most consequential first. Open one for its reasons and full description; descriptions are the publisher's own words.

5 tools

Can't be undone 1Sends, pays, publishes or merges: once done, it cannot be taken back.Claude Code: ask

simulate_withdrawalMonte Carlo simulation of withdrawing a yearly percentage of a starting balance, raised with inflation every month, from a portfolio (the 4% rule and its variants).1 finding
Why it is in this group
- The name "simulate_withdrawal" says "withdrawal": a word that usually means money moves, which cannot be taken back.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
Findings
- Warn
  The server marks "simulate_withdrawal" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".
  Matched text
  annotations: {"readOnlyHint":true,"idempotentHint":true,"openWorldHint":false}; The name "simulate_withdrawal" says "withdrawal": a word that usually means money moves, which cannot be taken back.
  What this check looks for
Description, as the server wrote it
Monte Carlo simulation of withdrawing a yearly percentage of a starting balance, raised with inflation every month, from a portfolio (the 4% rule and its variants). Returns the share of paths that still had money at the end, when the others ran out, the remaining balance range in today's money, the success rate at withdrawal rates from 2% to 8%, and a compoundsim.app url.
Annotations the server declares
- readOnlyHint: true
- idempotentHint: true
- openWorldHint: false

Changes things 3Creates or changes something that can be changed back.Claude Code: ask

compare_portfoliosRuns the same monthly-investing plan through 2 to 4 portfolios (the same simulation as simulate_portfolio) and returns each one's final outcome range, deepest fall, past return and…Reads text others write1 finding
Why it is in this group
- The name "compare_portfolios" says "compare": a word for reading.
- The description's first verb is "run": a word for a change.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe description's first sentence says "run" and "url": it reads web pages, which anyone can write.
Findings
- Warn
  The server marks "compare_portfolios" read-only (readOnlyHint: true), and its own name, description or input give the class "write".
  Matched text
  annotations: {"readOnlyHint":true,"idempotentHint":true,"openWorldHint":false}; The name "compare_portfolios" says "compare": a word for reading.
  What this check looks for
Description, as the server wrote it
Runs the same monthly-investing plan through 2 to 4 portfolios (the same simulation as simulate_portfolio) and returns each one's final outcome range, deepest fall, past return and volatility, and url, for questions like 'S&P 500 or all-country stocks?'.
Annotations the server declares
- readOnlyHint: true
- idempotentHint: true
- openWorldHint: false
simulate_fixed_rateDeterministic compound growth of monthly contributions (plus an optional starting sum) at a fixed annual return.No findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
Description, as the server wrote it
Deterministic compound growth of monthly contributions (plus an optional starting sum) at a fixed annual return. Returns contributions, gains and total by year, and a compoundsim.app url. Use simulate_portfolio for the range of outcomes of real assets.
Annotations the server declares
- readOnlyHint: true
- idempotentHint: true
- openWorldHint: false
simulate_portfolioMonte Carlo simulation of investing monthly (plus an optional starting sum) in one asset or a mix rebalanced monthly.No findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
Description, as the server wrote it
Monte Carlo simulation of investing monthly (plus an optional starting sum) in one asset or a mix rebalanced monthly. Returns the range of outcomes by year (10th to 90th percentile), the deepest fall along the way, the mix's own past return and volatility, and a compoundsim.app url that shows the same scenario.
Annotations the server declares
- readOnlyHint: true
- idempotentHint: true
- openWorldHint: false

Only reads 1Looks things up and changes nothing.Show 1 read-only tool

get_asset_returnsAnnualised past returns of the assets compoundsim simulates, over the last 5, 10 or 20 years, all the data, or a calendar span: total return with dividends reinvested, price return…Reads private dataNo findings
Why it is in this group
- The name "get_asset_returns" says "get": a word for reading.
What it can reach
- private-dataThe description's first sentence says "calendar": it reads calendars.
Description, as the server wrote it
Annualised past returns of the assets compoundsim simulates, over the last 5, 10 or 20 years, all the data, or a calendar span: total return with dividends reinvested, price return, the dividends' share, volatility, and the return after US inflation (in USD) or the exchange rate's share of the return (in another currency).
Annotations the server declares
- readOnlyHint: true
- idempotentHint: true
- openWorldHint: false

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Exfil surface

Which tools read private data, which read text someone else can write, and which can send data out. One of each is a path a prompt injection can use.

No private-data, untrusted-input, outbound path in this server alone: no tool is tagged outbound.

Reads private data1: Reads files, mail, messages, databases, secrets, calendars or repositories.; get_asset_returns
Reads text others write1: Brings in text someone else can write: web pages, inbound email, messages, issues and comments.; compare_portfolios
Can send data out0: Can carry data to people or systems: it sends, posts or publishes, or takes a recipient, channel or URL.

Other servers in the same agent add their own tools to these paths. Audit your whole setup to see them together.

Findings

Matches of fixed checks, with the text they matched.

2 warn

Warncompare_portfolios
The server marks "compare_portfolios" read-only (readOnlyHint: true), and its own name, description or input give the class "write".
Matched text
annotations: {"readOnlyHint":true,"idempotentHint":true,"openWorldHint":false}; The name "compare_portfolios" says "compare": a word for reading.
What this check looks for
Warnsimulate_withdrawal
The server marks "simulate_withdrawal" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".
Matched text
annotations: {"readOnlyHint":true,"idempotentHint":true,"openWorldHint":false}; The name "simulate_withdrawal" says "withdrawal": a word that usually means money moves, which cannot be taken back.
What this check looks for

History

Changes to its tool definitions and to its remote endpoint, newest first.

No change seen yet. Its tools are rescanned every day, and a remote endpoint is looked at once a week.

All changes to this server

Install

Pinned to version 1.0.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http compoundsim https://compoundsim.app/mcp

claude mcp add --transport http compoundsim https://compoundsim.app/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change or a way out, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json

{
  "permissions": {
    "allow": [
      "mcp__compoundsim__get_asset_returns"
    ],
    "ask": [
      "mcp__compoundsim__simulate_portfolio",
      "mcp__compoundsim__compare_portfolios",
      "mcp__compoundsim__simulate_withdrawal",
      "mcp__compoundsim__simulate_fixed_rate"
    ],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. A read that can send data out (it takes a URL, say) asks first too. It assumes the server is installed as compoundsim. Review it before you use it.

Capability tags behind 2 rules

mcp__compoundsim__compare_portfolios untrusted-input
mcp__compoundsim__get_asset_returns private-data

Keep the decision: fail CI when the tools change, follow every change, or show a badge.

Pin in CI

Fail a build when the tools you reviewed are not the tools the server serves today.

curl -s "https://anlyon.dev/api/v1/servers/app.compoundsim/compoundsim/verify?hash=8aa141d7867343883ad5c95568e29d4b8e34fd19e6ea0d98287a2226334e8473" | jq -e '.changed == false'

Pinned hash 8aa141d78673, from Nov 1, 2026, 17:18 UTC.

Watch

Get told when its tools change: a new tool, a new description, a new class.

https://anlyon.dev/servers/app.compoundsim/compoundsim/changes.xml

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Badge

[![anlyon.dev](https://anlyon.dev/badge/app.compoundsim/compoundsim.svg)](https://anlyon.dev/servers/app.compoundsim/compoundsim)

Source: MCP Registry. Synced Nov 1, 2026, 17:17 UTC.