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Olivier Chafik 89a684546b
 fix(examples): resolve DIST_DIR path for npm package execution (#277) 
* fix(examples): resolve DIST_DIR path for npm package execution

When servers are compiled to dist/server.js and published to npm,
`import.meta.dirname` already points to dist/, so joining with "dist"
results in dist/dist/ which doesn't exist.

This fix detects whether we're running from TypeScript source or
compiled JavaScript and adjusts the path accordingly:
- From source (server.ts): use dist/ subdirectory
- From compiled (dist/server.js): use current directory

Fixes ENOENT errors like:
"ENOENT: no such file or directory, open '.../dist/dist/mcp-app.html'"

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(pdf-server): mark pdfjs-dist as external in bundle

The pdf.worker.mjs file wasn't being found when running from npm
because bun bundled pdfjs-dist but didn't include the worker file.

By marking pdfjs-dist as external, it uses the installed package
from node_modules at runtime where the worker is available.

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
2026-01-15 12:23:13 +00:00
..
src feat: use structuredContent with outputSchema in example servers (#220) 2026-01-12 14:25:16 +00:00
.gitignore Improve consistency and organization of examples for AI learning 2026-01-13 20:48:02 -06:00
grid-cell.png feat(basic-host): URL params, fullscreen mode, unified layout (#266) 2026-01-14 22:09:41 +00:00
main.ts feat: compile example servers to JavaScript for npm consumption (#259) 2026-01-14 23:46:17 +00:00
mcp-app.html Add color-scheme meta tag to all example apps 2025-12-15 11:42:18 -08:00
package.json feat: compile example servers to JavaScript for npm consumption (#259) 2026-01-14 23:46:17 +00:00
README.md Smoothen the process of getting started (#103) 2025-12-09 16:15:32 +01:00
screenshot.png feat(basic-host): URL params, fullscreen mode, unified layout (#266) 2026-01-14 22:09:41 +00:00
server.ts fix(examples): resolve DIST_DIR path for npm package execution (#277) 2026-01-15 12:23:13 +00:00
tsconfig.json Add cohort-heatmap-server example 2025-12-04 14:32:53 -06:00
tsconfig.server.json feat: compile example servers to JavaScript for npm consumption (#259) 2026-01-14 23:46:17 +00:00
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