fix: mini hardening

application/api/user/agents/portability.py

@@ -888,6 +888,38 @@ def _tool_key(index: int) -> str:
 # ---------------------------------------------------------------------------
 
 
+def _plan_workflow_removal(conn, user: str, target: dict) -> Optional[dict]:
+    """Describe what an explicit ``workflow: null`` would destroy, if anything.
+
+    Returns a ``delete`` block sized with the current graph, or None when the
+    workflow survives — the target is new, published (``_apply_workflow``
+    keeps a published agent's graph), has no workflow, or another agent still
+    references it.
+    """
+    if target.get("action") != "update" or not target.get("agent_id"):
+        return None
+    if (target.get("status") or "") == "published":
+        return None
+    agent_row = AgentsRepository(conn).get(str(target["agent_id"]), user) or {}
+    existing_id = agent_row.get("workflow_id")
+    if not existing_id:
+        return None
+    row = WorkflowsRepository(conn).get(str(existing_id), user)
+    if row is None:
+        return None
+    if AgentsRepository(conn).count_by_workflow(str(existing_id), user) > 1:
+        return None
+    # Lazy import, same as _apply_workflow — keeps route modules decoupled at load.
+    from application.api.user.workflows.routes import get_workflow_graph_version
+
+    version = get_workflow_graph_version(row)
+    return {
+        "action": "delete",
+        "nodes": len(WorkflowNodesRepository(conn).find_by_version(str(row["id"]), version)),
+        "edges": len(WorkflowEdgesRepository(conn).find_by_version(str(row["id"]), version)),
+    }
+
+
 def plan_import(conn, user: str, doc: dict) -> dict:
     """Resolve every reference without writing; returns a resolution report."""
     spec = doc["spec"]
@@ -978,18 +1010,25 @@ def plan_import(conn, user: str, doc: dict) -> dict:
 
     workflow_plan = None
     wf_spec = spec.get("workflow")
-    if spec.get("agent_type") == "workflow" and isinstance(wf_spec, dict):
-        action = "create"
-        if target.get("action") == "update" and target.get("agent_id"):
-            agent_row = AgentsRepository(conn).get(str(target["agent_id"]), user)
-            existing_wf = (agent_row or {}).get("workflow_id")
-            if existing_wf and WorkflowsRepository(conn).get(str(existing_wf), user):
-                action = "update"
-        workflow_plan = {
-            "nodes": len(wf_spec.get("nodes") or []),
-            "edges": len(wf_spec.get("edges") or []),
-            "action": action,
-        }
+    if spec.get("agent_type") == "workflow":
+        if isinstance(wf_spec, dict):
+            action = "create"
+            if target.get("action") == "update" and target.get("agent_id"):
+                agent_row = AgentsRepository(conn).get(str(target["agent_id"]), user)
+                existing_wf = (agent_row or {}).get("workflow_id")
+                if existing_wf and WorkflowsRepository(conn).get(str(existing_wf), user):
+                    action = "update"
+            workflow_plan = {
+                "nodes": len(wf_spec.get("nodes") or []),
+                "edges": len(wf_spec.get("edges") or []),
+                "action": action,
+            }
+        elif "workflow" in spec:
+            # Explicit ``workflow: null`` (vs. an omitted key, which changes
+            # nothing). Apply clears the link and reaps the row when no other
+            # agent references it, destroying the graph, its run history and
+            # its artifacts — the dry-run has to say so before the user commits.
+            workflow_plan = _plan_workflow_removal(conn, user, target)
 
     return {
         "target": target,
@@ -1029,7 +1068,19 @@ def _apply_sources(conn, user: str, spec: dict, resolution: dict, warnings: list
         mapping = {}
     resolved: list[str] = []
     id_by_name: dict[str, Optional[str]] = {}
-    for src in spec.get("sources") or []:
+    entries = [src for src in spec.get("sources") or [] if isinstance(src, dict)]
+    # ``id_by_name`` (and a workflow node's source reference) keys on the name
+    # alone, but names aren't unique per user — ``find_by_name`` returns the
+    # oldest match, so duplicates collapse onto one source. Same hazard the
+    # custom-model display names carry below; surface it rather than silently
+    # rewiring a node to a different source.
+    names = [src.get("name") or "" for src in entries]
+    for dup in sorted({n for n in names if n and names.count(n) > 1}):
+        warnings.append(
+            f"Multiple sources share the name '{dup}'; references to it all "
+            "resolve to the oldest one"
+        )
+    for src in entries:
         name = src.get("name") or ""
         id_by_name.setdefault(name, None)
         mapped = mapping.get(name)
@@ -1338,7 +1389,9 @@ def _rewrite_node_refs(
             resolved_sources.append(ref)
         else:
             warnings.append(f"Workflow node source '{ref}' not resolved; removed")
-    cfg["sources"] = resolved_sources
+    # Distinct names can collapse onto one source (see ``_apply_sources``), so
+    # dedupe rather than storing the same id twice on the node.
+    cfg["sources"] = list(dict.fromkeys(resolved_sources))
 
     raw_model = cfg.get("model_id")
     if raw_model:
@@ -1536,6 +1589,12 @@ def apply_import(conn, user: str, doc: dict, resolution: Optional[dict] = None)
                 "extra_source_ids": [],
             }
         )
+        prior_workflow_id = None
+        if is_update:
+            prior_workflow_id = (
+                agents_repo.get(str(target["agent_id"]), user) or {}
+            ).get("workflow_id")
+        published = (target.get("status") or "") == "published"
         workflow_result = _apply_workflow(
             conn,
             user,
@@ -1546,21 +1605,31 @@ def apply_import(conn, user: str, doc: dict, resolution: Optional[dict] = None)
             model_ids_by_name,
             warnings,
         )
-        if workflow_result is not _WORKFLOW_UNCHANGED:
-            if workflow_result is None and (target.get("status") or "") == "published":
-                warnings.append(
-                    "File has no workflow; the published agent kept its existing one"
+        # A published workflow agent with no graph can't run — the create and
+        # update routes both reject that state, so import must not install it
+        # through the back door (e.g. a file that flips ``agent_type`` to
+        # workflow over a published classic agent).
+        if workflow_result is _WORKFLOW_UNCHANGED:
+            if published and not prior_workflow_id:
+                raise AgentImportError(
+                    "A published workflow agent needs a workflow; this file has none"
                 )
-            else:
-                authoritative["workflow_id"] = workflow_result
-                if workflow_result is None and is_update:
-                    # Explicit ``workflow: null`` on a draft: remember the old
-                    # link so the row can be reaped after the update — there is
-                    # no workflow-list API independent of agents, so an
-                    # unlinked workflow would be unreachable forever.
-                    prior = agents_repo.get(str(target["agent_id"]), user) or {}
-                    if prior.get("workflow_id"):
-                        orphaned_workflow_id = str(prior["workflow_id"])
+        elif workflow_result is None and published:
+            if not prior_workflow_id:
+                raise AgentImportError(
+                    "A published workflow agent needs a workflow; this file has none"
+                )
+            warnings.append(
+                "File has no workflow; the published agent kept its existing one"
+            )
+        else:
+            authoritative["workflow_id"] = workflow_result
+            if workflow_result is None and prior_workflow_id:
+                # Explicit ``workflow: null`` on a draft: remember the old
+                # link so the row can be reaped after the update — there is
+                # no workflow-list API independent of agents, so an
+                # unlinked workflow would be unreachable forever.
+                orphaned_workflow_id = str(prior_workflow_id)
 
     # Optional fields — applied only when present so a partial file doesn't wipe them.
     optional = {
@@ -1583,6 +1652,12 @@ def apply_import(conn, user: str, doc: dict, resolution: Optional[dict] = None)
                 # Nothing references it anymore; delete (cascades nodes/edges
                 # and reaps run artifacts) rather than stranding the row.
                 WorkflowsRepository(conn).delete(orphaned_workflow_id, user)
+                # Destructive and irreversible — the graph, its run history and
+                # its artifacts (rows and stored bytes) all go. Say so.
+                warnings.append(
+                    "File has no workflow; the agent's workflow was deleted "
+                    "along with its run history and artifacts"
+                )
             return {
                 "agent_id": str(target["agent_id"]),
                 "action": "updated",

frontend/src/agents/AgentCard.tsx

@@ -17,12 +17,14 @@ import Trash from '../assets/red-trash.svg';
 import ThreeDots from '../assets/three-dots.svg';
 import UnPin from '../assets/unpin.svg';
 import { Avatar } from '../components/ui/avatar';
+import { Button } from '../components/ui/button';
 import {
   DropdownMenu,
   DropdownMenuContent,
   DropdownMenuItem,
   DropdownMenuTrigger,
 } from '../components/ui/dropdown-menu';
+import { Modal } from '../components/ui/modal';
 import ConfirmationModal from '../modals/ConfirmationModal';
 import MoveToFolderModal from '../modals/MoveToFolderModal';
 import { ActiveState } from '../models/misc';
@@ -67,6 +69,7 @@ export default function AgentCard({
     useState<ActiveState>('INACTIVE');
   const [moveModalState, setMoveModalState] = useState<ActiveState>('INACTIVE');
   const [shareModalOpen, setShareModalOpen] = useState(false);
+  const [exportError, setExportError] = useState<string | null>(null);
 
   const menuOptionsConfig: Record<string, AgentMenuOption[]> = {
     template: [
@@ -302,7 +305,12 @@ export default function AgentCard({
           .json()
           .then((data) => data?.message)
           .catch(() => null);
-        throw new Error(message || t('agents.exportAgentFailed'));
+        // Server-side refusals (e.g. a workflow referencing too many
+        // resources) carry an actionable message; flag it so the catch can
+        // tell it apart from a transport error like "Failed to fetch".
+        const error = new Error(message || t('agents.exportAgentFailed'));
+        error.name = 'ExportRefused';
+        throw error;
       }
       const yamlText = await response.text();
       const blob = new Blob([yamlText], { type: 'application/x-yaml' });
@@ -316,8 +324,10 @@ export default function AgentCard({
       URL.revokeObjectURL(url);
     } catch (error) {
       console.error('Error:', error);
-      alert(
-        error instanceof Error ? error.message : t('agents.exportAgentFailed'),
+      setExportError(
+        error instanceof Error && error.name === 'ExportRefused'
+          ? error.message
+          : t('agents.exportAgentFailed'),
       );
     }
   };
@@ -470,6 +480,25 @@ export default function AgentCard({
         cancelLabel="Cancel"
         variant="danger"
       />
+      <Modal
+        open={exportError !== null}
+        onOpenChange={(open) => {
+          if (!open) setExportError(null);
+        }}
+        title={t('agents.exportAgentFailed')}
+        size="sm"
+        footer={
+          <Button
+            type="button"
+            onClick={() => setExportError(null)}
+            className="rounded-3xl px-5"
+          >
+            {t('agents.close')}
+          </Button>
+        }
+      >
+        <p className="text-muted-foreground text-sm">{exportError}</p>
+      </Modal>
       <MoveToFolderModal
         modalState={moveModalState}
         setModalState={setMoveModalState}

frontend/src/locale/de.json

@@ -1032,6 +1032,7 @@
       "willUpdate": "Updates an existing agent (matched by {{matchedBy}}).",
       "workflowCreate": "Includes a workflow with {{nodes}} nodes — it will be created for you.",
       "workflowUpdate": "Includes a workflow with {{nodes}} nodes — your existing workflow will be updated.",
+      "workflowDelete": "Includes no workflow — the agent's existing workflow ({{nodes}} nodes), its run history and its artifacts will be permanently deleted.",
       "sources": "Sources",
       "tools": "Tools",
       "models": "Models",
@@ -1152,6 +1153,7 @@
     "importAgent": "Import",
     "exportAgent": "Export as YAML",
     "exportAgentFailed": "Failed to export agent",
+    "close": "Schließen",
     "shareWithTeam": "Mit Team teilen",
     "backToAll": "Zurück zu allen Agenten",
     "pageHeader": {

frontend/src/locale/en.json

@@ -1037,6 +1037,7 @@
       "willUpdate": "Updates an existing agent (matched by {{matchedBy}}).",
       "workflowCreate": "Includes a workflow with {{nodes}} nodes — it will be created for you.",
       "workflowUpdate": "Includes a workflow with {{nodes}} nodes — your existing workflow will be updated.",
+      "workflowDelete": "Includes no workflow — the agent's existing workflow ({{nodes}} nodes), its run history and its artifacts will be permanently deleted.",
       "sources": "Sources",
       "tools": "Tools",
       "models": "Models",
@@ -1161,6 +1162,7 @@
     "importAgent": "Import",
     "exportAgent": "Export as YAML",
     "exportAgentFailed": "Failed to export agent",
+    "close": "Close",
     "shareWithTeam": "Share with team",
     "backToAll": "Back to all agents",
     "pageHeader": {

frontend/src/locale/es.json

@@ -1032,6 +1032,7 @@
       "willUpdate": "Updates an existing agent (matched by {{matchedBy}}).",
       "workflowCreate": "Includes a workflow with {{nodes}} nodes — it will be created for you.",
       "workflowUpdate": "Includes a workflow with {{nodes}} nodes — your existing workflow will be updated.",
+      "workflowDelete": "Includes no workflow — the agent's existing workflow ({{nodes}} nodes), its run history and its artifacts will be permanently deleted.",
       "sources": "Sources",
       "tools": "Tools",
       "models": "Models",
@@ -1152,6 +1153,7 @@
     "importAgent": "Import",
     "exportAgent": "Export as YAML",
     "exportAgentFailed": "Failed to export agent",
+    "close": "Cerrar",
     "shareWithTeam": "Compartir con el equipo",
     "backToAll": "Volver a todos los agentes",
     "pageHeader": {

frontend/src/locale/jp.json

@@ -1032,6 +1032,7 @@
       "willUpdate": "Updates an existing agent (matched by {{matchedBy}}).",
       "workflowCreate": "Includes a workflow with {{nodes}} nodes — it will be created for you.",
       "workflowUpdate": "Includes a workflow with {{nodes}} nodes — your existing workflow will be updated.",
+      "workflowDelete": "Includes no workflow — the agent's existing workflow ({{nodes}} nodes), its run history and its artifacts will be permanently deleted.",
       "sources": "Sources",
       "tools": "Tools",
       "models": "Models",
@@ -1152,6 +1153,7 @@
     "importAgent": "Import",
     "exportAgent": "Export as YAML",
     "exportAgentFailed": "Failed to export agent",
+    "close": "閉じる",
     "shareWithTeam": "チームと共有",
     "backToAll": "すべてのエージェントに戻る",
     "pageHeader": {

frontend/src/locale/ru.json

@@ -1032,6 +1032,7 @@
       "willUpdate": "Updates an existing agent (matched by {{matchedBy}}).",
       "workflowCreate": "Includes a workflow with {{nodes}} nodes — it will be created for you.",
       "workflowUpdate": "Includes a workflow with {{nodes}} nodes — your existing workflow will be updated.",
+      "workflowDelete": "Includes no workflow — the agent's existing workflow ({{nodes}} nodes), its run history and its artifacts will be permanently deleted.",
       "sources": "Sources",
       "tools": "Tools",
       "models": "Models",
@@ -1152,6 +1153,7 @@
     "importAgent": "Import",
     "exportAgent": "Export as YAML",
     "exportAgentFailed": "Failed to export agent",
+    "close": "Закрыть",
     "shareWithTeam": "Поделиться с командой",
     "backToAll": "Вернуться ко всем агентам",
     "pageHeader": {

frontend/src/locale/zh-TW.json

@@ -1032,6 +1032,7 @@
       "willUpdate": "Updates an existing agent (matched by {{matchedBy}}).",
       "workflowCreate": "Includes a workflow with {{nodes}} nodes — it will be created for you.",
       "workflowUpdate": "Includes a workflow with {{nodes}} nodes — your existing workflow will be updated.",
+      "workflowDelete": "Includes no workflow — the agent's existing workflow ({{nodes}} nodes), its run history and its artifacts will be permanently deleted.",
       "sources": "Sources",
       "tools": "Tools",
       "models": "Models",
@@ -1152,6 +1153,7 @@
     "importAgent": "Import",
     "exportAgent": "Export as YAML",
     "exportAgentFailed": "Failed to export agent",
+    "close": "關閉",
     "shareWithTeam": "與團隊分享",
     "backToAll": "返回所有代理",
     "pageHeader": {

frontend/src/locale/zh.json

@@ -1032,6 +1032,7 @@
       "willUpdate": "Updates an existing agent (matched by {{matchedBy}}).",
       "workflowCreate": "Includes a workflow with {{nodes}} nodes — it will be created for you.",
       "workflowUpdate": "Includes a workflow with {{nodes}} nodes — your existing workflow will be updated.",
+      "workflowDelete": "Includes no workflow — the agent's existing workflow ({{nodes}} nodes), its run history and its artifacts will be permanently deleted.",
       "sources": "Sources",
       "tools": "Tools",
       "models": "Models",
@@ -1152,6 +1153,7 @@
     "importAgent": "Import",
     "exportAgent": "Export as YAML",
     "exportAgentFailed": "Failed to export agent",
+    "close": "关闭",
     "shareWithTeam": "与团队共享",
     "backToAll": "返回所有代理",
     "pageHeader": {

frontend/src/modals/ImportAgentModal.tsx

@@ -1,6 +1,6 @@
 import { AlertTriangle, CheckCircle2 } from 'lucide-react';
 import { useState } from 'react';
-import { useDropzone } from 'react-dropzone';
+import { type FileRejection, useDropzone } from 'react-dropzone';
 import { useTranslation } from 'react-i18next';
 import { useSelector } from 'react-redux';
 import { useNavigate } from 'react-router-dom';
@@ -58,7 +58,7 @@ type ImportPlan = {
   workflow?: {
     nodes: number;
     edges: number;
-    action: 'create' | 'update';
+    action: 'create' | 'update' | 'delete';
   } | null;
 };
 
@@ -124,19 +124,28 @@ export default function ImportAgentModal({
     setYamlText(await selectedFile.text());
   };
 
-  const { getRootProps, getInputProps, isDragActive } = useDropzone({
-    onDrop: (acceptedFiles: File[]) => {
-      if (acceptedFiles[0]) processFile(acceptedFiles[0]);
-    },
-    multiple: false,
-    // Declared here (not via getInputProps) so drag-and-drop is filtered
-    // too, with drag-over rejection feedback; processFile's extension check
-    // stays as a backstop for odd MIME reports.
-    accept: {
-      'application/x-yaml': ['.yaml', '.yml'],
-      'text/yaml': ['.yaml', '.yml'],
-    },
-  });
+  const { getRootProps, getInputProps, isDragActive, isDragReject } =
+    useDropzone({
+      onDrop: (acceptedFiles: File[], fileRejections: FileRejection[]) => {
+        // A rejected file never reaches acceptedFiles, so without this the
+        // drop is a silent no-op and any previously picked file stays staged.
+        if (fileRejections.length > 0) {
+          setFileName('');
+          setYamlText('');
+          setError(t('modals.importAgent.invalidFileType'));
+          return;
+        }
+        if (acceptedFiles[0]) processFile(acceptedFiles[0]);
+      },
+      multiple: false,
+      // Declared here (not via getInputProps) so drag-and-drop is filtered
+      // too; processFile's extension check stays as a backstop for odd MIME
+      // reports.
+      accept: {
+        'application/x-yaml': ['.yaml', '.yml'],
+        'text/yaml': ['.yaml', '.yml'],
+      },
+    });
 
   const handleAnalyze = async () => {
     if (!yamlText) return;
@@ -320,7 +329,11 @@ export default function ImportAgentModal({
             <div
               {...getRootProps({
                 className: `border-border hover:border-primary flex cursor-pointer flex-col items-center justify-center rounded-xl border-2 border-dashed p-8 transition-colors ${
-                  isDragActive ? 'border-primary' : ''
+                  isDragReject
+                    ? 'border-destructive'
+                    : isDragActive
+                      ? 'border-primary'
+                      : ''
                 }`,
               })}
             >
@@ -346,18 +359,28 @@ export default function ImportAgentModal({
                 : t('modals.importAgent.willCreate')}
             </div>
 
-            {plan.workflow && (
-              <p className="flex items-center gap-2 text-sm">
-                <CheckCircle2 className="h-4 w-4 text-green-600 dark:text-green-400" />
-                {plan.workflow.action === 'update'
-                  ? t('modals.importAgent.workflowUpdate', {
-                      nodes: plan.workflow.nodes,
-                    })
-                  : t('modals.importAgent.workflowCreate', {
-                      nodes: plan.workflow.nodes,
-                    })}
-              </p>
-            )}
+            {plan.workflow &&
+              (plan.workflow.action === 'delete' ? (
+                // Irreversible: the graph, its run history and its artifacts
+                // all go. Warn rather than confirming with a green check.
+                <p className="text-destructive flex items-center gap-2 text-sm">
+                  <AlertTriangle className="h-4 w-4 shrink-0" />
+                  {t('modals.importAgent.workflowDelete', {
+                    nodes: plan.workflow.nodes,
+                  })}
+                </p>
+              ) : (
+                <p className="flex items-center gap-2 text-sm">
+                  <CheckCircle2 className="h-4 w-4 text-green-600 dark:text-green-400" />
+                  {plan.workflow.action === 'update'
+                    ? t('modals.importAgent.workflowUpdate', {
+                        nodes: plan.workflow.nodes,
+                      })
+                    : t('modals.importAgent.workflowCreate', {
+                        nodes: plan.workflow.nodes,
+                      })}
+                </p>
+              ))}
 
             {plan.sources.length > 0 && (
               <Section title={t('modals.importAgent.sources')}>

frontend/src/modals/ImportSpecModal.tsx

@@ -1,5 +1,5 @@
 import { useState } from 'react';
-import { useDropzone } from 'react-dropzone';
+import { type FileRejection, useDropzone } from 'react-dropzone';
 import { useTranslation } from 'react-i18next';
 import { useSelector } from 'react-redux';
 
@@ -73,19 +73,28 @@ export default function ImportSpecModal({
     setParsedResult(null);
   };
 
-  const { getRootProps, getInputProps, isDragActive } = useDropzone({
-    onDrop: (acceptedFiles: File[]) => {
-      if (acceptedFiles[0]) processFile(acceptedFiles[0]);
-    },
-    multiple: false,
-    // Declared here (not via getInputProps) so drag-and-drop is filtered
-    // too; processFile's extension check stays as a backstop.
-    accept: {
-      'application/json': ['.json'],
-      'application/x-yaml': ['.yaml', '.yml'],
-      'text/yaml': ['.yaml', '.yml'],
-    },
-  });
+  const { getRootProps, getInputProps, isDragActive, isDragReject } =
+    useDropzone({
+      onDrop: (acceptedFiles: File[], fileRejections: FileRejection[]) => {
+        // A rejected file never reaches acceptedFiles, so without this the
+        // drop is a silent no-op and any previously picked file stays staged.
+        if (fileRejections.length > 0) {
+          setFile(null);
+          setParsedResult(null);
+          setError(t('modals.importSpec.invalidFileType'));
+          return;
+        }
+        if (acceptedFiles[0]) processFile(acceptedFiles[0]);
+      },
+      multiple: false,
+      // Declared here (not via getInputProps) so drag-and-drop is filtered
+      // too; processFile's extension check stays as a backstop.
+      accept: {
+        'application/json': ['.json'],
+        'application/x-yaml': ['.yaml', '.yml'],
+        'text/yaml': ['.yaml', '.yml'],
+      },
+    });
 
   const handleParse = async () => {
     if (!file) return;
@@ -209,7 +218,11 @@ export default function ImportSpecModal({
             <div
               {...getRootProps({
                 className: `border-border dark:border-border hover:border-primary dark:hover:border-primary flex cursor-pointer flex-col items-center justify-center rounded-xl border-2 border-dashed p-8 transition-colors ${
-                  isDragActive ? 'border-primary' : ''
+                  isDragReject
+                    ? 'border-destructive'
+                    : isDragActive
+                      ? 'border-primary'
+                      : ''
                 }`,
               })}
             >

tests/api/test_workflow_portability.py

@@ -408,3 +408,128 @@ def test_null_workflow_keeps_row_still_referenced_by_another_agent(pg_conn):
     assert updated["workflow_id"] is None
     # Still referenced — must not be deleted.
     assert WorkflowsRepository(pg_conn).get(str(wf["id"]), user) is not None
+
+
+def test_publish_guard_rejects_workflow_agent_with_no_graph(pg_conn):
+    """A file that makes a published agent a graph-less workflow agent is refused.
+
+    The create and update routes both reject that state; import must not
+    install it through the back door.
+    """
+    user = "u_wf_publish_guard"
+    agent = AgentsRepository(pg_conn).create(
+        user, "Probe Bot", "published", agent_type="classic", slug="probe-bot"
+    )
+    doc = {
+        "apiVersion": "docsgpt.arc53.com/v1",
+        "kind": "Agent",
+        "metadata": {"id": str(agent["id"]), "slug": "probe-bot"},
+        "spec": {"name": "Probe Bot", "agent_type": "workflow"},
+    }
+
+    # Key omitted entirely.
+    with pytest.raises(AgentImportError, match="published workflow agent needs a workflow"):
+        apply_import(pg_conn, user, doc)
+
+    # Explicit null, with no prior workflow to fall back on.
+    doc["spec"]["workflow"] = None
+    with pytest.raises(AgentImportError, match="published workflow agent needs a workflow"):
+        apply_import(pg_conn, user, doc)
+
+    unchanged = AgentsRepository(pg_conn).get(str(agent["id"]), user)
+    assert unchanged["agent_type"] == "classic"
+    assert unchanged["status"] == "published"
+
+
+def test_plan_distinguishes_absent_workflow_from_explicit_null(pg_conn):
+    """Omitting the key is a no-op; an explicit null destroys the graph.
+
+    The two used to produce an identical plan, so the modal showed nothing
+    either way while the outcomes differed completely.
+    """
+    user = "u_wf_plan_null"
+    agent, wf = _seed_workflow_agent(pg_conn, user)
+    AgentsRepository(pg_conn).update(str(agent["id"]), user, {"status": "draft"})
+    doc = parse_agent_yaml(agent_to_yaml(serialize_agent(pg_conn, agent, user)))
+
+    absent = parse_agent_yaml(agent_to_yaml(serialize_agent(pg_conn, agent, user)))
+    del absent["spec"]["workflow"]
+    assert plan_import(pg_conn, user, absent)["workflow"] is None
+
+    doc["spec"]["workflow"] = None
+    assert plan_import(pg_conn, user, doc)["workflow"] == {
+        "action": "delete",
+        "nodes": 3,
+        "edges": 2,
+    }
+
+
+def test_plan_reports_no_removal_when_workflow_survives(pg_conn):
+    """No delete block when the row lives on — published, or still referenced."""
+    user = "u_wf_plan_keep"
+    agent, wf = _seed_workflow_agent(pg_conn, user)
+    doc = parse_agent_yaml(agent_to_yaml(serialize_agent(pg_conn, agent, user)))
+    doc["spec"]["workflow"] = None
+
+    # Published: _apply_workflow keeps the existing graph.
+    assert plan_import(pg_conn, user, doc)["workflow"] is None
+
+    # Draft, but a sibling agent still references the row.
+    AgentsRepository(pg_conn).update(str(agent["id"]), user, {"status": "draft"})
+    AgentsRepository(pg_conn).create(
+        user, "Sibling", "draft", agent_type="workflow", workflow_id=str(wf["id"])
+    )
+    assert plan_import(pg_conn, user, doc)["workflow"] is None
+
+
+def test_null_workflow_deletion_is_warned_about(pg_conn):
+    """The destructive reap must not be silent."""
+    user = "u_wf_null_warn"
+    agent, wf = _seed_workflow_agent(pg_conn, user)
+    doc = parse_agent_yaml(agent_to_yaml(serialize_agent(pg_conn, agent, user)))
+    doc["spec"]["workflow"] = None
+    AgentsRepository(pg_conn).update(str(agent["id"]), user, {"status": "draft"})
+
+    result = apply_import(pg_conn, user, doc)
+    assert WorkflowsRepository(pg_conn).get(str(wf["id"]), user) is None
+    assert any("was deleted" in w and "run history" in w for w in result["warnings"])
+
+
+def test_duplicate_source_names_warn_and_dedupe(pg_conn):
+    """Two sources sharing a name collapse onto the oldest — say so."""
+    user = "u_wf_dup_src"
+    repo = SourcesRepository(pg_conn)
+    older = repo.create("KB", user_id=user, type="file")
+    newer = repo.create("KB", user_id=user, type="file")
+    agent, _wf = _seed_workflow_agent(pg_conn, user, source_id=str(older["id"]))
+
+    # Point the node at both same-named sources.
+    version = 1
+    nodes_repo = WorkflowNodesRepository(pg_conn)
+    node = [n for n in nodes_repo.find_by_version(str(agent["workflow_id"]), version)
+            if n["node_type"] == "agent"][0]
+    config = dict(node["config"])
+    config["sources"] = [str(older["id"]), str(newer["id"])]
+    nodes_repo.bulk_create(
+        str(agent["workflow_id"]),
+        version,
+        [{
+            "node_id": node["node_id"],
+            "node_type": node["node_type"],
+            "title": node.get("title"),
+            "position": node.get("position"),
+            "config": config,
+        }],
+    )
+
+    doc = parse_agent_yaml(agent_to_yaml(serialize_agent(pg_conn, agent, user)))
+    assert [s["name"] for s in doc["spec"]["sources"]] == ["KB", "KB"]
+
+    result = apply_import(pg_conn, user, doc)
+    assert any("share the name 'KB'" in w for w in result["warnings"])
+
+    updated = AgentsRepository(pg_conn).get(str(agent["id"]), user)
+    graph_nodes, _ = _graph(pg_conn, WorkflowsRepository(pg_conn).get(str(updated["workflow_id"]), user))
+    agent_node = [n for n in graph_nodes if n["node_type"] == "agent"][0]
+    # Collapsed onto the oldest match, and not stored twice.
+    assert agent_node["config"]["sources"] == [str(older["id"])]