Method _extract_result_value

src/mcp_cli/chat/tool_processor.py:1265–1338

Extract the actual value from MCP response structures. MCP responses can be nested in various ways: 1. Direct value (number, string) 2. Dict with "content" containing MCP ToolResult with .content list 3. Dict with "success"/"result" wrapper 4. List of content

(self, result: Any)

            return {}

    def _extract_result_value(self, result: Any) -> Any:
        """Extract the actual value from MCP response structures.

        MCP responses can be nested in various ways:
        1. Direct value (number, string)
        2. Dict with "content" containing MCP ToolResult with .content list
        3. Dict with "success"/"result" wrapper
        4. List of content blocks [{type: "text", text: "..."}]
        5. Object with .content attribute (MCP CallToolResult)
        6. String representation like "content=[{'type': 'text', 'text': '4.2426'}]"

        This normalizes all formats to extract the core value for binding.
        """
        if result is None:
            return None

        # Handle string "None" (bug in some MCP responses)
        if result == "None" or result == "null":
            return None

        # Handle MCP CallToolResult object (has .content attribute)
        if hasattr(result, "content") and isinstance(result.content, list):
            return self._extract_from_content_list(result.content)

        # Handle dict structures
        if isinstance(result, dict):
            # Case: {"content": <MCP ToolResult object>}
            if "content" in result:
                content = result["content"]
                # MCP ToolResult has a .content attribute that's a list
                if hasattr(content, "content"):
                    return self._extract_from_content_list(content.content)
                # Or it might be a direct list
                if isinstance(content, list):
                    return self._extract_from_content_list(content)
                # Or a string
                if isinstance(content, str):
                    return self._try_parse_number(content)

            # Case: {"success": true, "result": ...}
            if "success" in result and "result" in result:
                inner = result["result"]
                # Recurse if inner is not None/string "None"
                if inner is not None and inner != "None":
                    return self._extract_result_value(inner)
                return None

            # Case: {"isError": false, "content": ...} (MCP response wrapper)
            if "isError" in result:
                if result.get("isError"):
                    return result.get("error") or result.get("content")
                return self._extract_result_value(result.get("content"))

            # Case: {"text": "value"} direct
            if "text" in result and isinstance(result["text"], str):
                return self._try_parse_number(result["text"])

        # Handle list of content blocks directly