CompoundSim
Project how monthly investing or retirement withdrawals could play out, using past market returns for real assets.
Runs compound-growth and Monte Carlo simulations on S&P 500, Nasdaq 100 and other asset mixes using past returns. Compares portfolios, estimates retirement withdrawal success rates, and returns a shareable scenario link. No account needed.
Try asking Muse: "Show me the likely range of what I'd have in 25 years if I put 500 a month into an S&P 500 index fund, adjusted for 3% inflation."
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Source: Found in the official MCP Registry (app.compoundsim/compoundsim) · First listed November 1, 2026
Last 24 hours
Each bar is one check, every 15 minutes. Green means it answered. Last checked 3 h ago.
Is it safe to connect?
What Muse can see: It does not ask you to sign in, so it cannot see your accounts. It only sees what Muse sends it from your request.
Before it acts: Read what Muse plans to do before you approve it, and remove the app from Muse when you stop using it.
musedirectory.ai is not part of Meta. More about how Muse handles your information
How to add it to Muse
Not in Muse's Connectors list yet, but Muse can still use it. Copy the request below and paste it into Muse. Muse asks before it shares anything with the app's site. Meta does not review apps used this way, so only use ones you trust. We tested this in the Muse app on September 24, 2026: Muse used an app's link directly this way and returned a live answer.
https://compoundsim.app/mcpNot in Muse's Connectors list yet. Muse can still use it: its page gives you a request to paste into Muse.
Also use it in ChatGPT or Claude
CompoundSim is a remote MCP server, so any assistant that can add a custom connector by link can use it. Same link, same tools.
Add it to ChatGPT
- 1
Open ChatGPT settings
In ChatGPT, open Settings, then Connectors (called Apps & Connectors on some accounts).
- 2
Turn on developer mode
Under Advanced settings, switch on Developer mode. That is what lets you add a connector by link.
- 3
Create the connector
Choose Create, give it a name, paste the link as the MCP server URL, and save. If it needs a sign-in, ChatGPT asks for it here.
- 4
Use it in a chat
Start a chat, open the tools menu, pick the connector, and ask. ChatGPT asks before it runs a tool the first time.
Custom connectors need a paid ChatGPT plan, and on Team, Enterprise and Edu accounts only an admin can add them. Our "Working" label means the server answered us; it cannot tell whether your plan lets you add it. All connectors that work in ChatGPT
Add it to Claude
- 1
Open Claude settings
In Claude, open Settings, then Connectors.
- 2
Add a custom connector
Choose Add custom connector, give it a name, and paste the link.
- 3
Connect and use it
If it needs a sign-in, Claude sends you to it. Then turn the connector on in a chat from the tools menu and ask.
Custom connectors are available on paid Claude plans; on Team and Enterprise accounts an admin may need to add them. Our "Working" label means the server answered us; it cannot tell whether your plan lets you add it. All connectors that work in Claude
https://compoundsim.app/mcpWhat people ask Muse to do
Technical details: safety screening, tools, response time and recent checks
Response time at the last check: 266ms. Worked in n/a of checks over 30 days.
Screening · November 1, 2026
Screened, no issues found
Screening looks for known threats and hidden instructions at the time of the check, and runs again weekly and whenever the tool list changes. It cannot see the server's code, so only connect what you need and review what Muse asks to do. How screening works.
Tools · 5
simulate_portfolioMonte 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 ucompare_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 volatility, and url, for questions like 'S&P 500 or all-country stocks?'.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). Returns the share of paths that still had money at the end, when the others ran out, the remaining balance range insimulate_fixed_rateDeterministic 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.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, the dividends' share, volatility, and the return after US inflation (in USD) or the exchange rate'Link
https://compoundsim.app/mcpQuestions about CompoundSim in Muse
How do I connect CompoundSim to Muse?
Not in Muse's Connectors list yet, but Muse can still use it. Paste this into Muse: "Use CompoundSim to help me. It is a free service with an MCP server at https://compoundsim.app/mcp. It does not need an API key. Ask me before you share anything with it." Muse asks before it shares anything with the app's site. Meta does not review apps used this way, so only use ones you trust. We tested this in the Muse app on September 24, 2026: Muse used an app's link directly this way and returned a live answer.
Is CompoundSim working right now?
At the last check (November 1, 2026, 16:31 UTC) the endpoint was working, answering in 266ms. It is checked every 15 minutes.
Is CompoundSim safe to connect to Muse?
It was screened on November 1, 2026 with the result "screened, no issues found". Screening checks the domain against threat feeds and reads the tools for hidden instructions and requests for passwords or card numbers. It cannot see the server's code, so grant only the access you need.
What can CompoundSim do in Muse?
It exposes 5 tools, including simulate_portfolio, compare_portfolios, simulate_withdrawal, simulate_fixed_rate. For example, you could ask Muse: "Show me the likely range of what I'd have in 25 years if I put 500 a month into an S&P 500 index fund, adjusted for 3% inflation."
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This listing was added from public sources (Found in the official MCP Registry (app.compoundsim/compoundsim)). If you build CompoundSim, claim it to correct the details and get your badge.
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