ChurnLens

Buyer-side SaaS due-diligence maths: NRR, GRR, revenue concentration, zombie MRR, LTV:CAC.

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What it can do

    What data it sees

    Do you need an account

    No: the server works without sign-in

    Buyer-side SaaS due-diligence maths: NRR, GRR, revenue concentration, zombie MRR, LTV:CAC.

    How to connect

    How to connect ChurnLens to Claude

    The server address to paste into Claude settings:

    https://churnlens.site/api/mcp

    1. Open Claude (claude.ai or the desktop app).
    2. Go to Settings → Connectors.
    3. Click Add custom connector.
    4. Paste the server address copied below into Remote MCP server URL and click Add.
    5. In a chat, click + → Connectors and switch the new connector on.

    Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

    Authorization

    After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

    How to connect ChurnLens to ChatGPT

    The server address to paste into ChatGPT settings:

    https://churnlens.site/api/mcp

    1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
    2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
    3. Open Settings → Connectors and click Create.
    4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
    5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
    6. In a new chat open + → Apps/Connectors and enable the connector.

    OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

    Authorization

    On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

    How to connect ChurnLens to Cursor

    The server address to paste into Cursor settings:

    https://churnlens.site/api/mcp

    Fastest: click Open in Cursor below and confirm the prompt.

    Manually:

    1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
    2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
    3. Save the file. The server appears in the MCP list; authorize it there if asked.

    Authorization

    If the service needs sign-in, an authorize button appears next to the server in the MCP list.

    Server tool list (6)

    Raw names from tools/list. Only developers need these.

    calculate_churn_rateCalculate net revenue retention (NRR), gross revenue retention (GRR), revenue churn and implied customer lifetime from one period's MRR movements. Also reports the NRR-minus-GRR spread, which reveals how much churn is being masked by expansion revenue.
    analyze_revenue_concentrationAssess customer concentration risk across a book of revenue using the Herfindahl-Hirschman Index (HHI), top-N share and whale detection. Answers the question every acquirer asks first: how much revenue walks out with one logo?
    detect_zombie_mrrIdentify dormant-but-paying accounts — revenue that still counts in MRR but whose customers have stopped showing up. Zombie revenue is one renewal notice from cancelling and is invisible to standard revenue dashboards.
    score_saas_healthScore a SaaS business 0-100 across five dimensions — retention, growth, concentration, efficiency and durability — and return the composite. Every mapping is published, so the score can be reconstructed by hand.
    calculate_ltvCalculate gross-margin-adjusted customer lifetime value, the LTV:CAC ratio and CAC payback in months. Omitting gross margin yields lifetime revenue rather than lifetime value — usually a third of the number.
    get_scoring_bandsReturn the scoring thresholds ChurnLens applies to NRR, revenue concentration and the composite health score. These are bands, not measured benchmark data — the sourced benchmark figures are cited at https://churnlens.site/benchmarks.