modelcontextprotocol/ext-apps
Watch
1
0
Fork
You've already forked ext-apps
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions
ext-apps/examples/cohort-heatmap-server
History
Exact
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Olivier Chafik ecc593bcec
 chore: release 0.3.0 (#204) 
* chore: bump version to 0.3.0

Breaking changes:
- `viewport` replaced with `containerDimensions` in host context

New examples:
- video-resource-server
- sheet-music-server

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* fix(video-resource-server): add missing server-utils and fix import path

The video-resource-server was importing from a non-existent
../shared/server-utils.js path. Added the server-utils.ts file
and fixed the import to use ./src/server-utils.js like other examples.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* chore: update ext-apps version refs to 0.3.0

---------

Co-authored-by: Claude <noreply@anthropic.com>
2026-01-09 00:55:45 +00:00
..
src feat: publish example servers to npm (#184) 2026-01-08 20:08:50 +00:00
mcp-app.html Add color-scheme meta tag to all example apps 2025-12-15 11:42:18 -08:00
package.json chore: release 0.3.0 (#204) 2026-01-09 00:55:45 +00:00
README.md Smoothen the process of getting started (#103) 2025-12-09 16:15:32 +01:00
server-utils.ts feat: publish example servers to npm (#184) 2026-01-08 20:08:50 +00:00
server.ts feat: publish example servers to npm (#184) 2026-01-08 20:08:50 +00:00
tsconfig.json Add cohort-heatmap-server example 2025-12-04 14:32:53 -06:00
vite.config.ts Add cohort-heatmap-server example 2025-12-04 14:32:53 -06:00

README.md

Example: Cohort Heatmap App

A demo MCP App that displays cohort retention data as an interactive heatmap, showing customer retention over time by signup month.

Initial view Hover state Low retention hover

Features

  • Cohort Retention Heatmap: Color-coded grid showing retention percentages across cohorts and time periods
  • Multiple Metrics: Switch between Retention %, Revenue Retention, and Active Users
  • Period Types: View data by monthly or weekly intervals
  • Interactive Exploration: Hover cells for detailed tooltips, click to highlight rows/columns
  • Color Scale: Green (high retention) through yellow to red (low retention)
  • Theme Support: Adapts to light/dark mode preferences

Running

  1. Install dependencies:

    npm install

  2. Build and start the server:

    npm run start:http  # for Streamable HTTP transport
# OR
npm run start:stdio  # for stdio transport

  3. View using the basic-host example or another MCP Apps-compatible host.

Architecture

Server (server.ts)

Exposes a single get-cohort-data tool that returns:

  • Cohort rows with signup month, original user count, and retention cells
  • Period headers and labels
  • Configurable parameters: metric type, period type, cohort count, max periods

The tool generates synthetic cohort data using an exponential decay model with configurable retention curves per metric type.

App (src/mcp-app.tsx)

  • Uses React for the heatmap visualization
  • Fetches data on mount and when filters change
  • Displays retention percentages in a grid with HSL color interpolation
  • Shows detailed tooltips on hover with user counts and exact retention values
  • Supports row/column highlighting on cell click