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Jonathan Hefner 4ff22d0097
 Fix build errors in examples (#180) 
* Update `package.json`

* Add TypeScript type checking to example build scripts

Add `tsc --noEmit &&` before `vite build` in all example `package.json`
files to catch type errors during builds. Previously, type errors
in `server.ts` files were not detected because Vite/Bun transpile
without type checking.

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

* Make `_meta` optional in `McpUiAppResourceConfig`

The `_meta` and `ui` properties were required, causing TypeScript errors
when calling `registerAppResource()` without providing metadata.

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

* Fix Zod type compatibility in `registerAppTool()`

Use `ZodRawShapeCompat | AnySchema` from SDK's `zod-compat` module
instead of raw `ZodRawShape` to resolve type errors when examples
pass `ZodObject` schemas to `registerAppTool()`.

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

* Remove unused imports in example apps

- `basic-server-react`: Remove unused `McpUiResourceTeardownResult`
- `customer-segmentation-server`: Remove unused `PostMessageTransport`

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* Fix CI git install test for fork PRs

Use `github.event.pull_request.head.repo.full_name` to correctly
reference the fork repository when testing git installs from PRs.

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---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
2025-12-18 11:17:23 +00:00
..
src Use content instead of structuredContent in examples 2025-12-05 16:35:20 -06:00
mcp-app.html Add color-scheme meta tag to all example apps 2025-12-15 11:42:18 -08:00
package.json Fix build errors in examples (#180) 2025-12-18 11:17:23 +00:00
README.md Smoothen the process of getting started (#103) 2025-12-09 16:15:32 +01:00
server.ts fix(examples): use server.registerTool for non-UI tool + fix missing imports (#173) 2025-12-17 00:17:45 +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