# Why Did You Render

> Use this tool when you need to diagnose and optimize React application performance by capturing re-render diagnostic reports from the browser. It solves problems related to identifying unnecessary re-renders, improving rendering efficiency, and enhancing overall application responsiveness. The tool takes browser rendering data as input and outputs real-time diagnostic reports via WebSocket relay and JSONL storage, making it ideal for use cases involving complex React applications and real-time debugging.

Canonical page: https://skillsregistry.net/skills/0x1f320-why-did-you-render  
JSON: https://api.skillsregistry.net/v1/skills/0x1f320-why-did-you-render

## Description

Why Did You Render captures React re-render diagnostic reports from the browser and exposes them to AI coding agents via MCP. Consists of two npm packages: a server-side MCP component and a browser client. Uses WebSocket relay and JSONL storage for real-time debugging data.

## Trust

- **Trust score (0–1):** 0.97
- **Verification tier:** verified
- **Last scanned:** 2026-09-28

## Facts

- **Version:** 1.0.0
- **Skill type:** atomic
- **Execution layer:** mcp-remote
- **Runtime environment:** api
- **Category:** browser-automation
- **Updated:** 2026-09-28

## Source

- **Source listing:** [PulseMCP](https://www.pulsemcp.com/servers/0x1f320-why-did-you-render)
- **Repository:** <https://github.com/0x1f320/why-did-you-render-mcp>

## Use it

Resolve this record through the SkillsRegistry MCP server (no auth, read-only):

```
claude mcp add --transport http --scope user skillsregistry https://api.skillsregistry.net/mcp
```

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "get_skill",
    "arguments": {
      "slug": "0x1f320-why-did-you-render"
    }
  }
}
```

REST: `GET https://api.skillsregistry.net/v1/skills/0x1f320-why-did-you-render` · pull for local use: `GET https://api.skillsregistry.net/v1/skills/0x1f320-why-did-you-render/pull`

---
SkillsRegistry indexes agent skills from public registries and GitHub. Skills we have analysed are scanned with Circle-IR and scored on six dimensions; each listing states its scan coverage. More: https://skillsregistry.net/llms.txt