Initial implementation

src/infospace_bench/errors.py

@@ -0,0 +1,25 @@
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from typing import Any
+
+
+@dataclass
+class InfospaceError(Exception):
+    """Structured application error suitable for CLI and API surfaces."""
+
+    code: str
+    message: str
+    detail: dict[str, Any] = field(default_factory=dict)
+
+    def __post_init__(self) -> None:
+        super().__init__(self.message)
+
+    def to_dict(self) -> dict[str, Any]:
+        return {
+            "error": {
+                "code": self.code,
+                "message": self.message,
+                "detail": self.detail,
+            }
+        }