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xcrun mcpbridge returns unparsed JSON string in content field instead of structuredContent #18371
Description
Xcode 26.3's mcpbridge transmits tool results as a JSON string embedded within the content field, rather than providing proper object data in the structuredContent field.
This behavior breaks strict MCP clients (like gemini-cli) which expect structuredContent for tool results.
Sample Payload
Below is an example of the non-compliant JSON-RPC response observed from xcrun mcpbridge:
{
"jsonrpc": "2.0",
"id": 1,
"result": {
"content": [
{
"type": "text",
"text": "{\"windows\":[{\"title\":\"HelloWorld\",\"path\":\"/path/to/project\"}]}"
}
]
// Missing: structuredContent
}
}The expected behavior would be for the text content to be parsed and populated into structuredContent, or for the structuredContent field to be present directly.
Expected Payload
The result object should contain a parsed structuredContent field:
{
"jsonrpc": "2.0",
"id": 1,
"result": {
"content": [
{
"type": "text",
"text": "..."
}
],
"structuredContent": {
"windows": [
{
"title": "HelloWorld",
"path": "/path/to/project"
}
]
}
}
}
Activity
[-]Enhance MCP tool result handling for Xcode 26.3 mcpbridge[/-][+][Xcode] MCP Bridge returns non-compliant responses missing structuredContent[/+][-][Xcode] MCP Bridge returns non-compliant responses missing structuredContent[/-][+]Bug: `xcrun mcpbridge` returns unparsed JSON string in `content` field instead of `structuredContent`[/+]fix(core): handle non-compliant mcpbridge responses from Xcode
[-]Bug: `xcrun mcpbridge` returns unparsed JSON string in `content` field instead of `structuredContent`[/-][+]`xcrun mcpbridge` returns unparsed JSON string in `content` field instead of `structuredContent`[/+]