diff --git a/flowbio/cli/_main.py b/flowbio/cli/_main.py
index 2196f08..e7fc634 100644
--- a/flowbio/cli/_main.py
+++ b/flowbio/cli/_main.py
@@ -89,7 +89,7 @@ def _dispatch(args: argparse.Namespace) -> int:
         output.emit_error(str(error))
         return int(ExitCode.USAGE)
     except FlowApiError as error:
-        details = error.errors if isinstance(error, AnnotationValidationError) else None
+        details = error.errors if isinstance(error, AnnotationValidationError) else error.details
         output.emit_error(
             error.message, status_code=error.status_code, details=details,
         )
diff --git a/flowbio/cli/_output.py b/flowbio/cli/_output.py
index f5839b1..739702f 100644
--- a/flowbio/cli/_output.py
+++ b/flowbio/cli/_output.py
@@ -94,13 +94,20 @@ def emit_raw(self, body: str) -> None:
 
 
 def format_issue(issue: JsonValue) -> str:
-    """Render a Flow ``{row, message}`` issue dict as a readable line.
+    """Render a Flow issue dict as a readable line.
 
-    Falls back to ``str`` for any other shape so unexpected payloads still
-    surface intact.
+    Handles both the annotation ``{row, message}`` shape and the API error
+    envelope's ``{field, code, message}`` detail shape, prefixing with whichever
+    locator is present. Falls back to ``str`` for any other shape so unexpected
+    payloads still surface intact.
     """
     if isinstance(issue, dict) and "message" in issue:
         row = issue.get("row")
-        prefix = f"row {row}: " if row is not None else ""
+        if row is not None:
+            prefix = f"row {row}: "
+        elif issue.get("field") is not None:
+            prefix = f"{issue['field']}: "
+        else:
+            prefix = ""
         return f"{prefix}{issue['message']}"
     return str(issue)
diff --git a/flowbio/v2/_transport.py b/flowbio/v2/_transport.py
index 7832c91..dbf1fb4 100644
--- a/flowbio/v2/_transport.py
+++ b/flowbio/v2/_transport.py
@@ -78,6 +78,7 @@ def _raise_for_error(self, response: httpx.Response) -> None:
         if response.is_success:
             return
 
+        details: list[dict] | None = None
         try:
             body = response.json()
         except ValueError:
@@ -85,11 +86,22 @@ def _raise_for_error(self, response: httpx.Response) -> None:
             # HTML/plain-text on 5xx instead of the API's JSON envelope.
             message = self._non_json_error_message(response)
         else:
-            message = body.get("error", body)
+            message, details = self._unpack_error_body(body)
         exception_class = self._STATUS_TO_EXCEPTION.get(
             response.status_code, FlowApiError,
         )
-        raise exception_class(response.status_code, message)
+        raise exception_class(response.status_code, message, details)
+
+    @staticmethod
+    def _unpack_error_body(body: dict) -> tuple[str | dict, list[dict] | None]:
+        error = body.get("error", body)
+        # The v2 API wraps errors in a {code, message, details} envelope; older
+        # endpoints put a bare string (or their own dict) under "error". Unwrap
+        # the envelope to its human message and per-field details, and leave any
+        # other shape untouched.
+        if isinstance(error, dict) and "message" in error:
+            return error["message"], error.get("details") or None
+        return error, None
 
     @staticmethod
     def _non_json_error_message(response: httpx.Response) -> str:
diff --git a/flowbio/v2/exceptions.py b/flowbio/v2/exceptions.py
index a035e76..71796ba 100644
--- a/flowbio/v2/exceptions.py
+++ b/flowbio/v2/exceptions.py
@@ -17,11 +17,20 @@ class FlowApiError(Exception):
     :param status_code: The HTTP status code from the response.
     :param message: The error message — either a string or a dict of
         field-level errors (e.g. ``{"field": ["error message"]}``).
+    :param details: Optional per-field problems from the server's error
+        envelope, each a ``{"field", "code", "message"}`` dict. Set when the
+        response carries the structured ``details`` list; ``None`` otherwise.
     """
 
-    def __init__(self, status_code: int, message: str | dict[str, list[str]]) -> None:
+    def __init__(
+        self,
+        status_code: int,
+        message: str | dict[str, list[str]],
+        details: list[dict] | None = None,
+    ) -> None:
         self.status_code = status_code
         self.message = message
+        self.details = details
         super().__init__(str(message))
 
 
diff --git a/setup.py b/setup.py
index 73479a2..bab87fd 100644
--- a/setup.py
+++ b/setup.py
@@ -5,7 +5,7 @@
 
 setup(
     name="flowbio",
-    version="0.11.0",
+    version="0.11.1",
     description="A client for the Flow API.",
     long_description=long_description,
     long_description_content_type="text/markdown",
diff --git a/tests/unit/cli/test_samples.py b/tests/unit/cli/test_samples.py
index e228779..23ef963 100644
--- a/tests/unit/cli/test_samples.py
+++ b/tests/unit/cli/test_samples.py
@@ -1151,10 +1151,17 @@ def test_trailing_blank_row_is_skipped(
     def test_api_rejection_propagates_as_error(
         self, run_cli, tmp_path: Path,
     ) -> None:
+        detail_message = "Sample type 'bogus' does not exist"
         route = respx.post(SAMPLE_IMPORTS_URL).mock(
             return_value=httpx.Response(
                 HTTPStatus.UNPROCESSABLE_ENTITY,
-                json={"error": "sample type 'bogus' does not exist"},
+                json={"error": {
+                    "code": "validation_error",
+                    "message": "Invalid sample import request",
+                    "details": [
+                        {"field": "0.sample_type", "code": "invalid", "message": detail_message},
+                    ],
+                }},
             ),
         )
         sheet = _write_import_sheet(tmp_path, _import_record(sample_type="bogus"))
@@ -1165,7 +1172,9 @@ def test_api_rejection_propagates_as_error(
 
         assert result.exit_code == 1
         assert route.call_count == 1
-        assert "bogus" in result.stderr
+        assert "Invalid sample import request" in result.stderr
+        assert f"0.sample_type: {detail_message}" in result.stderr
+        assert "{'" not in result.stderr
 
     @respx.mock
     def test_non_csv_sheet_is_usage_error(self, run_cli, tmp_path: Path) -> None:
@@ -1616,9 +1625,11 @@ def test_reports_job_with_no_execution_yet(self, run_cli) -> None:
 
     @respx.mock
     def test_unknown_job_id_is_not_found(self, run_cli) -> None:
+        not_found_message = "sample import 999 does not exist"
         respx.get(f"{SAMPLE_IMPORTS_URL}/999").mock(
             return_value=httpx.Response(
-                HTTPStatus.NOT_FOUND, json={"error": "sample import 999 does not exist"},
+                HTTPStatus.NOT_FOUND,
+                json={"error": {"code": "not_found", "message": not_found_message, "details": []}},
             ),
         )
 
@@ -1627,6 +1638,8 @@ def test_unknown_job_id_is_not_found(self, run_cli) -> None:
         )
 
         assert result.exit_code == 4
+        assert not_found_message in result.stderr
+        assert "{'" not in result.stderr
 
     def test_missing_job_id_is_usage_error(self, run_cli) -> None:
         result = run_cli("--token", TOKEN, "samples", "import-status")