MCP Server

Retirement Buddy's calculators are available to AI assistants over the Model Context Protocol. Connect it and your assistant can run an actual simulation rather than estimating one in prose.

The server

The endpoint is:

https://mcp.yourretirementbuddy.com/mcp

It is read-only, unauthenticated, and stores nothing. There is no account to create, no key to obtain, and no record kept of who called it or what they asked.

Connecting

Claude Code — add it from the command line:

claude mcp add --transport http retirement-buddy https://mcp.yourretirementbuddy.com/mcp

Claude Desktop and claude.ai — open Settings, then Connectors, then add a custom connector pointing at the URL above.

Any other MCP client — it speaks streamable HTTP and supports every protocol version the current MCP SDK speaks, 2024-10-07 through 2025-11-25.

The six tools

run_retirement_check

Takes:: Age, portfolio, annual spending. Optionally retirement age, income, savings rate, and expected Social Security.
Returns:: The probability the portfolio outlasts the plan, the 10th, 50th and 90th percentile balances at 90, and every assumption used to get there.

compare_social_security_claiming_ages

Takes:: Birth year and current income. Optionally years worked.
Returns:: Monthly and annual benefit at 62, at full retirement age, and at 70, the full retirement age for that birth year, whether the SSA maximum capped the figure, and the break-even ages between strategies.

estimate_tax_on_social_security

Takes:: Annual benefit and other income. Optionally tax-exempt interest and filing status.
Returns:: The taxable portion in dollars and as a share of the benefit, the provisional income figure it derives from, and which of the two thresholds it crossed.

estimate_rmd

Takes:: Age and pre-tax balance. Optionally spouse age and birth year.
Returns:: The IRS distribution factor, which table it came from, the required distribution, and the effective withdrawal percentage. Below the applicable age it reports that none is required and names the age of the first one.

estimate_home_affordability

Takes:: A US ZIP code and an all-in monthly housing budget. Optionally down payment, mortgage rate, and HOA dues.
Returns:: The supported home price and a full monthly breakdown — principal and interest, property tax, insurance, PMI, HOA — alongside local price percentiles.

get_retirement_buddy_info

Takes:: Nothing.
Returns:: What Retirement Buddy is, what it costs, who it is for, and its stated limitations.

What the numbers rest on

The simulation runs 2,000 paths to age 90, assuming a 7% average annual return with 15% volatility and 3% inflation, and models Social Security as beginning at 67 regardless of when work stops — so retiring earlier produces a gap the portfolio has to cover alone. It does not model long-term care, state taxes, or specific investments.

Every tool result carries the assumptions that produced it, so an assistant can state them alongside the number. The full detail is on the methodology page.

These are projections, not advice. Retirement Buddy is not a registered investment advisor and does not provide financial, investment, tax, or legal advice.

Trying it without an assistant

The MCP Inspector will list the tools and call them directly:

npx @modelcontextprotocol/inspector --cli https://mcp.yourretirementbuddy.com/mcp \
  --transport http --method tools/list