Mortgage Rate Intelligence MCP

Live 30yr/15yr/ARM mortgage rates from FRED, plus affordability index, payment calculator, and historical rate context from 2020–2026.

Returns a single comprehensive record per run with current rates, spread analysis, buyer guidance, payment scenarios across multiple purchase prices, and an affordability index comparing median income to median home price at current rates.

---

What It Returns

Field	Description
scenario	Run label
as_of_date	Date of rate data (FRED weekly release)
source	"FRED API (live)" or "FRED fallback database"
rate_30yr_fixed	Current 30-year fixed mortgage rate (%)
rate_15yr_fixed	Current 15-year fixed mortgage rate (%)
rate_5yr_arm	Current 5/1 ARM initial rate (%)
fed_funds_rate	Federal Funds Rate — primary Fed policy lever (%)
treasury_10yr	10-Year Treasury yield — benchmark for mortgage pricing (%)
spread_30yr_over_10yr	Mortgage spread over Treasuries (historically 1.5–2.5%; currently elevated)
spread_30yr_over_15yr	Premium for 30yr vs 15yr term
spread_note	Interpretation of current spread environment
rate_environment	Classification: Low / Below average / Moderate / Elevated / High
buyer_guidance	Actionable rate-environment advice for buyers
refinance_note	When refinancing makes sense
affordability_index	HAI-style index: >100 = median income can afford median home
qualifying_income_needed	Annual income required to qualify for median home at current rate
median_household_income	Current US median household income
median_home_price	Current US median home price
monthly_payment_median_home	P&I payment on median home at 20% down and current 30yr rate
pct_income_housing_median_buyer	Housing payment as % of median income
market_affordable_for_median_buyer	true/false affordability flag
trend_30yr	Rate direction: "declining" / "stable" / "rising"
trend_note	Trend magnitude and context
payment_scenarios	Array: monthly P&I + total interest for 5 purchase price tiers (or custom)
rate_history	Quarterly rate history 2020–2026 for context

Payment Scenario Fields (per price tier)

Field	Description
purchase_price	Home price
down_payment	Down payment amount (20% default)
loan_amount	Principal
monthly_pmt_30yr	30yr fixed monthly P&I
monthly_pmt_15yr	15yr fixed monthly P&I
monthly_pmt_5arm	5/1 ARM monthly P&I (initial 5yr period)
total_interest_30yr	Lifetime interest on 30yr loan
total_interest_15yr	Lifetime interest on 15yr loan
interest_savings_15yr	Interest saved by choosing 15yr over 30yr

---

Input Parameters

Parameter	Type	Required	Description
fred_api_key	string	No	FRED API key (DEMO_KEY used if omitted — 120 req/day)
purchase_price	number	No	Custom purchase price for payment scenarios
down_payment_pct	number	No	Down payment percentage (default: 20)
loan_amount	number	No	Override loan amount directly
show_rate_history	boolean	No	Include quarterly rate history 2020–2026 (default: true)
limit	integer	No	Reserved (single record output)

Get a free FRED API key at fred.stlouisfed.org/docs/api/api_key.html.

---

Example Inputs

Current rates snapshot (no key needed):

{}

Payment calculator for $450K home:

{
  "purchase_price": 450000,
  "down_payment_pct": 20
}

With your own FRED API key (higher rate limit):

{
  "fred_api_key": "your_key_here",
  "purchase_price": 550000,
  "down_payment_pct": 10
}

---

Example Output (truncated)

{
  "scenario": "Current Mortgage Rate Environment",
  "as_of_date": "2026-01-10",
  "source": "FRED API (live)",
  "rate_30yr_fixed": 6.48,
  "rate_15yr_fixed": 5.71,
  "rate_5yr_arm": 5.55,
  "fed_funds_rate": 3.58,
  "treasury_10yr": 4.32,
  "spread_30yr_over_10yr": 2.16,
  "spread_note": "30yr spread of 2.16% over 10yr Treasury is near normal (<2.5%)",
  "rate_environment": "Elevated (6-7%)",
  "buyer_guidance": "Lock rate if finding good deal; refinance opportunity likely within 2-3 years",
  "affordability_index": 74.2,
  "qualifying_income_needed": 108720,
  "median_household_income": 80610,
  "monthly_payment_median_home": 2104,
  "pct_income_housing_median_buyer": 31.3,
  "market_affordable_for_median_buyer": false,
  "trend_30yr": "declining",
  "trend_note": "30yr fixed moved -0.48% over last 8 weeks; current: 6.48%",
  "payment_scenarios": [
    {
      "purchase_price": 300000,
      "down_payment": 60000,
      "loan_amount": 240000,
      "monthly_pmt_30yr": 1514,
      "monthly_pmt_15yr": 1993,
      "monthly_pmt_5arm": 1361,
      "total_interest_30yr": 305040,
      "total_interest_15yr": 118740,
      "interest_savings_15yr": 186300
    }
  ]
}

---

Affordability Index Explained

The Affordability Index is modeled after the National Association of Realtors' Housing Affordability Index (HAI):

• Index = 100: Median income household qualifies exactly for the median-priced home at current rates with 20% down (using 28% front-end DTI rule)
• Index > 100: Median household can afford the median home (e.g., 120 = 20% above qualifying threshold)
• Index < 100: Median income falls short (e.g., 74 = only 74% of required income — typical 2024-2026 condition)

At 6.5% rates on a $420K median home, the monthly payment (~$2,100) consumes ~31% of the $80K median income — above the 28% threshold, meaning the market is unaffordable for the median buyer.

---

Rate History (2020–2026)

Period	30yr	15yr	5/1 ARM	Fed Funds	Note
2021-Q1	2.81%	2.21%	2.51%	0.25%	Historic lows
2022-Q4	6.90%	6.15%	5.68%	3.83%	Rapid hike cycle
2023-Q4	7.44%	6.74%	6.52%	5.33%	Peak rates
2024-Q4	6.72%	5.96%	5.75%	4.58%	Easing begins
2026-Q1	6.48%	5.71%	5.55%	3.58%	Current

---

Data Sources

• FRED (Federal Reserve Bank of St. Louis) — MORTGAGE30US, MORTGAGE15US, MORTGAGE5US, DGS10, FEDFUNDS
• Built-in fallback — curated rate history when FRED is unavailable or rate-limited

---

Use Cases

• AI agent deal underwriting — inject live rates into investment analysis workflows
• Buyer affordability coaching — show real payment impact at current rates by price tier
• Rate trend tracking — compare current environment to historical cycle
• Refinance decision support — assess spread and trend before advising action
• Market timing analysis — affordability index shows housing market stress level

---

Related Actors in the Real Estate Suite

• ../real-estate-intelligence-mcp/ — Property listings + deal scoring using live rate inputs
• ../rentcast-market-mcp/ — LTR rent estimates and vacancy rates
• ../str-market-intelligence-mcp/ — Airbnb/VRBO ADR, occupancy, and STR investment scores