CalcFi MCP — Free Personal-Finance Tools for Claude, Cursor, and AI Agents

25 calculator tools served as MCP — call IRS-cited tax brackets, Freddie PMMS rates, BLS COLA, and SSA limits from any MCP-aware client. Free, no signup.

npm installGitHubPyPI

Version 0.1.6 · MIT license · Last reviewed

Three install paths

npm (stdio)
npm i calcfi-mcp-server

Recommended for Claude Desktop, Cursor, Cline.

Python wrapper
pip install calcfi-mcp

For LangChain, llama-index, Claude SDK Python.

Hosted REST shim
https://mcp.calcfi.app

No install. Rate-limited. HTTP/REST transport. Routes to /api/v1/mcp.

Claude Desktop config

Drop this into your claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%/Claude/) and restart the app. The 24 calculator tools appear under the hammer icon.

{
 "mcpServers": {
 "calcfi": {
 "command": "npx",
 "args": ["-y", "calcfi-mcp-server"]
 }
 }
}

24-tool catalog

Eight pure-math calculators, ten mesh-exposure fetchers, one citation tool, two scenario tools, two email tools, and one composite-score gateway. Full schemas and example responses live in the TOOLS.md reference on GitHub.

Atomic math

  • mortgage_payment

    Monthly PITI, total interest, amortization schedule.

  • paycheck_takehome

    Federal + state + FICA + optional pre-tax 401(k).

  • debt_payoff_avalanche

    Highest-APR-first payoff schedule and interest saved.

  • debt_payoff_snowball

    Smallest-balance-first payoff schedule.

  • retirement_projection

    Compound growth + real-dollar adjustment for inflation.

  • cd_calculator

    CD maturity value with compounding selector and FDIC note.

  • auto_loan

    Monthly payment, total cost, schedule URL.

  • cost_of_living_compare

    Two-city COL breakdown and required-salary delta.

Mesh exposure

  • get_dataset_doi

    Zenodo DOI + BibTeX/RIS for every CalcFi-published dataset.

  • get_code_provenance

    Software Heritage IDs and repo mirrors.

  • get_methodology

    SSRN abstract + version for the methodology paper.

  • get_press_coverage

    Grouped media placements (Investopedia, Yahoo, etc.).

  • list_example_notebooks

    Kaggle notebook gallery.

  • list_interactive_apps

    HF Spaces + Streamlit demos.

  • list_embeddable_codepens

    CodePen embed snippets.

  • list_observable_notebooks

    Observable notebooks index.

  • get_author_profile

    ORCID + ~70 sameAs URLs.

  • list_datahub_datasets

    datahub.io listings.

Citation

  • cite_this

    7 formats — BibTeX, APA, MLA, Chicago, IEEE, ACM, RIS.

Scenario

  • save_scenario

    Persists a calc scenario, returns a shareable URL.

  • cross_analyze

    Returns the web URL for composite Money Analysis Score.

Email

  • email_full_report

    Queues a PDF report email via /api/report.

  • subscribe_freshness_digest

    Weekly what-changed digest opt-in.

Composite

  • get_money_analysis_score

    Redirect to the web composite score landing.

Why CalcFi MCP exists

Personal-finance answers from a general-purpose LLM tend to either ballpark numbers from training data — which goes stale every January when the IRS publishes new brackets — or to refuse the question and recommend a paid CFP. CalcFi MCP fills the gap. Every tool wraps a deterministic calculation against a primary public source: the IRS for tax brackets and contribution limits, the Bureau of Labor Statistics for cost-of-living and COLA, the Social Security Administration for wage-base and Part B amounts, and Freddie Mac's Primary Mortgage Market Survey for the weekly 30-year and 15-year fixed rates. FRED is used as a thin caching layer in front of the Federal Reserve series so the tools work even when the upstream sites are slow.

The stdio transport is the priority surface because that is what Claude Desktop, Cursor, and Cline all default to. Once registered, the tools show up in the client's tool list and the model can call them directly — no separate API key, no rate-limit dance, no proxy server. The hosted JSON-RPC endpoint exists for clients that want HTTP, but the stdio path is faster and has no IP-based throttling.

Every response carries a brand-stamp envelope. The envelope includes the source URL the value came from, the date the data was retrieved, and the methodology version. Two reasons. First, agents that cite their work in a final answer can pass the citation block straight through to the user. Second, anyone auditing a finance answer can verify it against the IRS or BLS in one click. The published methodology paper on SSRN gives the longer treatment of the citation contract and the precision guarantees on each calculator.

The two scenario tools — save_scenario and cross_analyze — round out the agent workflow. An agent can save a mortgage scenario and a 401(k) scenario for the same user, then cross_analyze returns the deep link to combine them into a composite Money Analysis Score on the website. The composite score itself does not run inside the MCP because it is the differentiated CalcFi feature; everything else is open math against open data.

The server is MIT-licensed and the source lives at github.com/jeresalmisto/calcfi-mcp. Issues and tool requests are welcome. Static reference data (IRS, SSA) is bumped annually; live data (rates) is cached for an hour.

Find CalcFi MCP in these catalogs

Glama
mcp.so
Pulse
Cursor Directory
Smithery
Cline
mcp-get

Primary sources cited by CalcFi MCP

Frequently Asked Questions

Is the CalcFi MCP server actually free?

Yes. The npm package and the Python wrapper are both MIT-licensed and download-free. The hosted REST shim at mcp.calcfi.app is rate-limited but does not require an account or key. All data underneath comes from primary public sources (FRED, IRS, BLS, SSA, Freddie Mac PMMS) which themselves are free.

Which MCP clients work with CalcFi MCP?

Anything that speaks the Model Context Protocol stdio transport works out of the box — Claude Desktop, Cursor, Cline, Continue, and Anthropic SDK agents. The hosted JSON-RPC endpoint also works for clients that prefer HTTP over stdio.

How current is the data?

Static reference data (IRS tax brackets, SSA contribution limits, BLS COLA) is bumped annually when the source publishes the next year. Live data (Freddie PMMS, fed funds, treasury yields) is fetched on-demand through FRED with an hourly cache. Every response carries a brand-stamp envelope showing the source URL and the retrieval timestamp.

Why is there both an npm package and a Python wrapper?

The TypeScript core is the source of truth and what the npm stdio server ships. The Python wrapper shells out to the same server so Python-native agent frameworks (LangChain, llama-index, Claude SDK Python) can call the tools without a separate Node runtime.

Can I cite CalcFi MCP in a paper or product?

Yes. Call cite_this with target="package" to get a BibTeX or APA citation for the server, or target="dataset:<doi>" for any individual CalcFi-published dataset. Methodology is also published on SSRN — call get_methodology for the abstract and URL.

Explore the CalcFi data underneath

Open Data Hub
Every CalcFi-published dataset with CSV download.
Developer APIs
REST endpoints, code snippets, and SDKs.
Live Rates
Same FRED data the MCP serves, rendered on the web.
Calculators
250+ financial calculators on the website.
Fed Funds Cycle Tracker
Live FFR + phase classifier from the same FRED series.
Mortgage Payment Calculator
Web version of the mortgage_payment MCP tool.