# mcp-use-hang-repro

> Use this tool when you need to diagnose and reproduce issues with dropped tool results in mcp-use dev, specifically when the handler completes after the widget iframe loads, causing a race condition. It helps solve problems related to inconsistent or lost data in development environments. The tool takes specific input parameters and outputs reproducible test cases to aid in debugging and troubleshooting.

Canonical page: https://skillsregistry.net/skills/cswkim-mcp-use-hang-repro  
JSON: https://api.skillsregistry.net/v1/skills/cswkim-mcp-use-hang-repro

## Description

Reproduces a race condition in mcp-use dev where tool results are dropped when the handler completes after the widget iframe loads.

## Trust

- **Trust score (0–1):** 0.69
- **Verification tier:** scanned
- **Last scanned:** 2026-08-30

## Facts

- **Version:** 1.0.0
- **Skill type:** atomic
- **Execution layer:** mcp-remote
- **Runtime environment:** api
- **Category:** other
- **Updated:** 2026-08-30

## Source

- **Source listing:** [Glama](https://glama.ai/mcp/servers/wou3bx0r3t)
- **Repository:** <https://github.com/cswkim/mcp-use-hang-repro>

## 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": "cswkim-mcp-use-hang-repro"
    }
  }
}
```

REST: `GET https://api.skillsregistry.net/v1/skills/cswkim-mcp-use-hang-repro` · pull for local use: `GET https://api.skillsregistry.net/v1/skills/cswkim-mcp-use-hang-repro/pull`

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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