aws-samples / aws-samples/amazon-bedrock-client-for-mac
[BUG] No STDIO MCP servers will start
- Dominant language
- Swift
- Stars
- 446
- Forks
- 45
- PR merge metrics
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Description
**Describe the bug**
Any STDIO MCP servers added will not start. Either the startup icon spins indefinitely or if toggled the status remains grey
**To Reproduce**
Steps to reproduce the behavior:
1. Go to 'Settings -> Enable MCP -> Configured Servers
2. Click on Add Server
3. Add the File System template with abs path to npx and shared directory
4. Server start up icon never turns green
**Expected behavior**
MCP server should be enabled and filesystem tools available
**Environment (required):**
- macOS version: 16.6 and 26.2
- Amazon Bedrock Client for Mac version: 1.4.3 (06ff2eeb)
**Log Files (optional)**
[2026-03-15T16:20:05Z] [info] [MCPManager.swift:124] MCP crash protection reset
[2026-03-15T16:20:05Z] [info] [MCPManager.swift:641] Executing MCP server via shell: /bin/zsh -l -c 'source ~/.zshrc 2>/dev/null || true; /opt/homebrew/bin/npx -y @modelcontextprotocol/server-filesystem /Users/ncrowe/Documents'
[2026-03-15T16:20:07Z] [warning] [Client.swift:204] Unexpected message received by client (not single/batch response or notification) ["message": ]0;ncrowe@:/{"result":{"protocolVersion":"2025-03-26","capabilities":{"tools":{"listChanged":true}},"serverInfo":{"name":"secure-filesystem-server","version":"0.2.0"}},"jsonrpc":"2.0","id":"D05BAB53-7227-4446-BEC8-97217AF73188"}]
```
{
"mcpServers" : {
"filesystem" : {
"enabled" : true,
"command" : "/opt/homebrew/bin/npx",
"type" : "stdio",
"args" : [
"-y",
"@modelcontextprotocol/server-filesystem",
"/Users/ncrowe/Documents"
]
}
}
}
```
**Additional context (optional)**
Executing the command from the logs manually works as expected.
```
/bin/zsh -l -c 'source ~/.zshrc 2>/dev/null || true; /opt/homebrew/bin/npx -y @modelcontextprotocol/server-filesystem /Users/ncrowe/Documents'
```
Using Filesystem as an example, but I've been unable to get any local MCP to work, all of which work in other applications like Claude Code or Cursor. When any local MCP is configured the message "MCP was automatically disabled due to repeated crashes" is always present in the settings on startup.
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