Xcode Tools 1.0 Release was released on 28 Sep 2003 and requires macOS 10.3+.
It can be downloaded from https://download.developer.apple.com/Mac_OS_X/Mac_OS_X_10.3_Build_7B85/7B85_Xcode_CD.dmg.
The SDKs it contains are:
- macOS 10.1.5 (Build 5S60)
- macOS 10.2.6 (Build 6L60)
- macOS 10.3 (Build 7B85)
The compilers it contains are:
- GCC 3.3 (Build 1495)