diff --git a/frontend/editor/src/cloud/components/shared/config/configSections/TeamSection.tsx b/frontend/editor/src/cloud/components/shared/config/configSections/TeamSection.tsx
index 4eb064d8bf..ab8a184828 100644
--- a/frontend/editor/src/cloud/components/shared/config/configSections/TeamSection.tsx
+++ b/frontend/editor/src/cloud/components/shared/config/configSections/TeamSection.tsx
@@ -360,11 +360,9 @@ const TeamSection: React.FC = () => {
           verticalSpacing="sm"
           withRowBorders
           highlightOnHover
-          style={
-            {
-              "--table-border-color": "var(--mantine-color-gray-3)",
-            } as React.CSSProperties
-          }
+          style={{
+            "--table-border-color": "var(--mantine-color-gray-3)",
+          }}
         >
           <Table.Thead>
             <Table.Tr
diff --git a/frontend/editor/src/core/components/fileEditor/FileEditor.tsx b/frontend/editor/src/core/components/fileEditor/FileEditor.tsx
index 8cfef80d83..1072758275 100644
--- a/frontend/editor/src/core/components/fileEditor/FileEditor.tsx
+++ b/frontend/editor/src/core/components/fileEditor/FileEditor.tsx
@@ -336,7 +336,7 @@ const FileEditor = ({
     (fileId: FileId) => {
       const index = stubsRef.current.findIndex((r) => r.id === fileId);
       if (index !== -1) {
-        setActiveFileId(fileId as string);
+        setActiveFileId(fileId);
         setActiveFileIndex(index);
         navActions.setWorkbench("viewer");
       }
@@ -410,10 +410,7 @@ const FileEditor = ({
                     onUnzipFile={handleUnzipFile}
                     toolMode={toolMode}
                     isSupported={isFileSupported(record.name)}
-                    policies={
-                      policyFileBadges.get(record.id as string) ??
-                      EMPTY_POLICIES
-                    }
+                    policies={policyFileBadges.get(record.id) ?? EMPTY_POLICIES}
                   />
                 );
               })}
diff --git a/frontend/editor/src/core/components/filesPage/FileDetailsPanel.tsx b/frontend/editor/src/core/components/filesPage/FileDetailsPanel.tsx
index 693d8efae7..ff570bbe1d 100644
--- a/frontend/editor/src/core/components/filesPage/FileDetailsPanel.tsx
+++ b/frontend/editor/src/core/components/filesPage/FileDetailsPanel.tsx
@@ -140,7 +140,7 @@ export function FileDetailsPanel({
     return null;
   }
 
-  const single = files.length === 1 ? files[0]! : null;
+  const single = files.length === 1 ? files[0] : null;
   const totalSize = files.reduce((sum, f) => sum + f.size, 0);
   const ext = single ? (single.name.split(".").pop() ?? "").toUpperCase() : "";
   // Files still needing a server upload; drives Save-to-server visibility.
diff --git a/frontend/editor/src/core/components/filesPage/FileGrid.tsx b/frontend/editor/src/core/components/filesPage/FileGrid.tsx
index 40e17dc502..334ad76805 100644
--- a/frontend/editor/src/core/components/filesPage/FileGrid.tsx
+++ b/frontend/editor/src/core/components/filesPage/FileGrid.tsx
@@ -422,7 +422,7 @@ function GridView(props: FileGridProps) {
               parentPath={entry.parentPath}
               isSelected={selectedFileIds.has(entry.file.id)}
               isInWorkspace={
-                activeWorkspaceFileIds?.has(entry.file.id as string) ?? false
+                activeWorkspaceFileIds?.has(entry.file.id) ?? false
               }
               selectedFileIds={selectedFileIds}
               multiSelectActive={selectedFileIds.size >= 2}
@@ -938,7 +938,7 @@ function FileCard({
                 shiftKey: false,
                 ctrlKey: true,
                 metaKey: true,
-              } as unknown as React.MouseEvent);
+              });
             }}
             onChange={() => {
               /* handled by onClick */
@@ -982,7 +982,7 @@ function FileCard({
             ·
           </span>
           <span>{fileDate}</span>
-          <PolicyBadges fileId={file.id as string} />
+          <PolicyBadges fileId={file.id} />
         </div>
       </div>
       <div className="files-page-card-actions">
@@ -1137,7 +1137,7 @@ function ListView(
               parentPath={entry.parentPath}
               isSelected={selectedFileIds.has(entry.file.id)}
               isInWorkspace={
-                activeWorkspaceFileIds?.has(entry.file.id as string) ?? false
+                activeWorkspaceFileIds?.has(entry.file.id) ?? false
               }
               selectedFileIds={selectedFileIds}
               multiSelectActive={selectedFileIds.size >= 2}
@@ -1424,7 +1424,7 @@ function FileRow({
                 shiftKey: false,
                 ctrlKey: true,
                 metaKey: true,
-              } as unknown as React.MouseEvent);
+              });
             }}
             onChange={() => {
               /* handled by onClick */
@@ -1491,7 +1491,7 @@ function FileRow({
           )}
         </span>
         <FileOriginBadge origin={getFileOrigin(file)} compact />
-        <PolicyBadges fileId={file.id as string} />
+        <PolicyBadges fileId={file.id} />
         {isInWorkspace && (
           <span className="files-page-row-open-pill">
             <span className="files-page-card-open-dot" />
diff --git a/frontend/editor/src/core/components/filesPage/FileManagerView.tsx b/frontend/editor/src/core/components/filesPage/FileManagerView.tsx
index 36ffb9c4dc..4665784e79 100644
--- a/frontend/editor/src/core/components/filesPage/FileManagerView.tsx
+++ b/frontend/editor/src/core/components/filesPage/FileManagerView.tsx
@@ -474,7 +474,7 @@ export default function FileManagerView() {
           if (idx >= 0 && lastIdx >= 0) {
             const [a, b] = idx < lastIdx ? [idx, lastIdx] : [lastIdx, idx];
             for (let i = a; i <= b; i += 1) {
-              next.add(visibleFiles[i]!.id);
+              next.add(visibleFiles[i].id);
             }
             return next;
           }
@@ -593,7 +593,7 @@ export default function FileManagerView() {
         });
         // Branch on requested stubs so already-active files still activate.
         if (materialized.length === 1) {
-          setActiveFileId(materialized[0]!.id);
+          setActiveFileId(materialized[0].id);
           navActions.setWorkbench("viewer");
         } else if (materialized.length > 1) {
           navActions.setWorkbench("fileEditor");
@@ -1172,7 +1172,7 @@ export default function FileManagerView() {
                   else if (e.key === "End") next = TAB_DEFS.length - 1;
                   else return;
                   e.preventDefault();
-                  const target = TAB_DEFS[next]!;
+                  const target = TAB_DEFS[next];
                   setCurrentTab(target.id);
                   focusTab(target.id);
                 }}
@@ -1602,7 +1602,7 @@ export default function FileManagerView() {
                         )
                       )
                         return;
-                      setViewMode(v as (typeof FILES_PAGE_VIEW_MODES)[number]);
+                      setViewMode(v);
                     }}
                     aria-label={t("filesPage.viewMode.label", "View mode")}
                     options={[
diff --git a/frontend/editor/src/core/components/filesPage/VersionTimeline.tsx b/frontend/editor/src/core/components/filesPage/VersionTimeline.tsx
index 05c96685b2..f484f936ef 100644
--- a/frontend/editor/src/core/components/filesPage/VersionTimeline.tsx
+++ b/frontend/editor/src/core/components/filesPage/VersionTimeline.tsx
@@ -120,14 +120,14 @@ export function VersionTimeline({
       };
   const rows: Row[] = useMemo(() => {
     if (!collapsible || showAllCollapsed) {
-      return ordered.map((v) => ({ kind: "version", version: v }) as Row);
+      return ordered.map<Row>((v) => ({ kind: "version", version: v }));
     }
     const head = ordered
       .slice(0, 3)
-      .map((v) => ({ kind: "version", version: v }) as Row);
+      .map<Row>((v) => ({ kind: "version", version: v }));
     const tail = ordered
       .slice(-2)
-      .map((v) => ({ kind: "version", version: v }) as Row);
+      .map<Row>((v) => ({ kind: "version", version: v }));
     const hidden = ordered.length - 5;
     return [...head, { kind: "ellipsis", hidden }, ...tail];
   }, [collapsible, showAllCollapsed, ordered]);
diff --git a/frontend/editor/src/core/components/filesPage/folderTreeWidth.ts b/frontend/editor/src/core/components/filesPage/folderTreeWidth.ts
index 4aaf8099ec..a88b0e7f11 100644
--- a/frontend/editor/src/core/components/filesPage/folderTreeWidth.ts
+++ b/frontend/editor/src/core/components/filesPage/folderTreeWidth.ts
@@ -27,7 +27,7 @@ function depthOf(
   let cursor: FolderRecord | undefined = folder;
   while (cursor && cursor.parentFolderId) {
     depth += 1;
-    cursor = byId.get(cursor.parentFolderId as string);
+    cursor = byId.get(cursor.parentFolderId);
     if (depth > 50) break;
   }
   return depth;
diff --git a/frontend/editor/src/core/components/mobileSign/MobileDrawCanvas.tsx b/frontend/editor/src/core/components/mobileSign/MobileDrawCanvas.tsx
index 38c2be8e6c..8461727240 100644
--- a/frontend/editor/src/core/components/mobileSign/MobileDrawCanvas.tsx
+++ b/frontend/editor/src/core/components/mobileSign/MobileDrawCanvas.tsx
@@ -139,9 +139,9 @@ export const MobileDrawCanvas = forwardRef<
     // where the per-frame synthetic event alone would drop curvature.
     const events =
       "getCoalescedEvents" in e.nativeEvent
-        ? (e.nativeEvent as PointerEvent).getCoalescedEvents()
+        ? e.nativeEvent.getCoalescedEvents()
         : [e.nativeEvent as PointerEvent];
-    const rect = (e.currentTarget as HTMLCanvasElement).getBoundingClientRect();
+    const rect = e.currentTarget.getBoundingClientRect();
     for (const ev of events) {
       stroke.points.push({
         x: ev.clientX - rect.left,
diff --git a/frontend/editor/src/core/components/onboarding/Onboarding.tsx b/frontend/editor/src/core/components/onboarding/Onboarding.tsx
index e95aaf57aa..3ce2e2701f 100644
--- a/frontend/editor/src/core/components/onboarding/Onboarding.tsx
+++ b/frontend/editor/src/core/components/onboarding/Onboarding.tsx
@@ -20,7 +20,6 @@ import {
 import { useOnboardingDownload } from "@app/components/onboarding/useOnboardingDownload";
 import {
   SLIDE_DEFINITIONS,
-  type SlideId,
   type ButtonAction,
 } from "@app/components/onboarding/onboardingFlowConfig";
 import ToolPanelModePrompt from "@app/components/tools/ToolPanelModePrompt";
@@ -322,7 +321,7 @@ export default function Onboarding() {
     ) {
       return null;
     }
-    return SLIDE_DEFINITIONS[currentStep.slideId as SlideId];
+    return SLIDE_DEFINITIONS[currentStep.slideId];
   }, [currentStep]);
 
   const currentSlideContent = useMemo(() => {
diff --git a/frontend/editor/src/core/components/pageEditor/commands/pageCommands.ts b/frontend/editor/src/core/components/pageEditor/commands/pageCommands.ts
index db9385fc37..2ce10b929c 100644
--- a/frontend/editor/src/core/components/pageEditor/commands/pageCommands.ts
+++ b/frontend/editor/src/core/components/pageEditor/commands/pageCommands.ts
@@ -244,7 +244,7 @@ export class ReorderPagesCommand extends DOMCommand {
         .map((pageNum) =>
           currentDoc.pages.find((p) => p.pageNumber === pageNum),
         )
-        .filter((page) => page !== undefined) as PDFPage[];
+        .filter((page) => page !== undefined);
 
       const remainingPages = currentDoc.pages.filter(
         (page) => !this.selectedPages!.includes(page.pageNumber),
diff --git a/frontend/editor/src/core/components/shared/superSearch/SuperSearch.test.tsx b/frontend/editor/src/core/components/shared/superSearch/SuperSearch.test.tsx
index f77984f090..931c87197f 100644
--- a/frontend/editor/src/core/components/shared/superSearch/SuperSearch.test.tsx
+++ b/frontend/editor/src/core/components/shared/superSearch/SuperSearch.test.tsx
@@ -84,7 +84,7 @@ function renderSearch(
     <MantineProvider>
       <SuperSearch
         inputId="test-super-search"
-        useResults={useResults as TestUseResultsHook | undefined}
+        useResults={useResults}
         scopes={scopes}
       />
     </MantineProvider>,
@@ -103,7 +103,7 @@ describe("SuperSearch", () => {
       width: 320,
       height: 40,
       toJSON: () => "",
-    } as DOMRect);
+    });
 
     Object.defineProperty(Element.prototype, "scrollIntoView", {
       value: vi.fn(),
diff --git a/frontend/editor/src/core/components/shared/wetSignature/SignatureTypeSelector.tsx b/frontend/editor/src/core/components/shared/wetSignature/SignatureTypeSelector.tsx
index 7b4950f4aa..5cc14fcf3c 100644
--- a/frontend/editor/src/core/components/shared/wetSignature/SignatureTypeSelector.tsx
+++ b/frontend/editor/src/core/components/shared/wetSignature/SignatureTypeSelector.tsx
@@ -19,7 +19,7 @@ export const SignatureTypeSelector: React.FC<SignatureTypeSelectorProps> = ({
   return (
     <SegmentedControl
       value={value}
-      onChange={(val) => onChange(val as SignatureType)}
+      onChange={(val) => onChange(val)}
       options={[
         {
           value: "draw",
diff --git a/frontend/editor/src/core/components/toast/ToastContext.tsx b/frontend/editor/src/core/components/toast/ToastContext.tsx
index a300dc1791..4fcc6d8b10 100644
--- a/frontend/editor/src/core/components/toast/ToastContext.tsx
+++ b/frontend/editor/src/core/components/toast/ToastContext.tsx
@@ -93,7 +93,7 @@ export function ToastProvider({ children }: { children: React.ReactNode }) {
               ? true
               : false,
         createdAt: Date.now(),
-      } as ToastInstance;
+      };
       setToasts((prev) => {
         // Coalesce duplicates by alertType + title + body text if no explicit id was provided
         if (!options.id) {
@@ -138,7 +138,7 @@ export function ToastProvider({ children }: { children: React.ReactNode }) {
           ...t,
           ...updates,
           progress,
-        } as ToastInstance;
+        };
 
         // Detect completion but do not auto-flip to success.
         // Callers (e.g., compare workbench) explicitly set alertType when done.
@@ -197,9 +197,8 @@ export function ToastProvider({ children }: { children: React.ReactNode }) {
         ),
       );
     };
-    window.addEventListener("toast:toggle", handler as EventListener);
-    return () =>
-      window.removeEventListener("toast:toggle", handler as EventListener);
+    window.addEventListener("toast:toggle", handler);
+    return () => window.removeEventListener("toast:toggle", handler);
   }, []);
 
   return (
diff --git a/frontend/editor/src/core/components/tools/FullscreenToolList.tsx b/frontend/editor/src/core/components/tools/FullscreenToolList.tsx
index 5296e21299..85a306c476 100644
--- a/frontend/editor/src/core/components/tools/FullscreenToolList.tsx
+++ b/frontend/editor/src/core/components/tools/FullscreenToolList.tsx
@@ -108,7 +108,7 @@ const FullscreenToolList = ({
         window.open(tool.link, "_blank", "noopener,noreferrer");
         return;
       }
-      onSelect(id as ToolId);
+      onSelect(id);
     };
 
     if (showDescriptions) {
@@ -274,15 +274,11 @@ const FullscreenToolList = ({
 
             {showDescriptions ? (
               <div className="tool-panel__fullscreen-grid tool-panel__fullscreen-grid--detailed">
-                {tools.map(({ id, tool }) =>
-                  renderToolItem(id as ToolId, tool),
-                )}
+                {tools.map(({ id, tool }) => renderToolItem(id, tool))}
               </div>
             ) : (
               <div className="tool-panel__fullscreen-list">
-                {tools.map(({ id, tool }) =>
-                  renderToolItem(id as ToolId, tool),
-                )}
+                {tools.map(({ id, tool }) => renderToolItem(id, tool))}
               </div>
             )}
           </section>
diff --git a/frontend/editor/src/core/components/tools/RightSidebar.tsx b/frontend/editor/src/core/components/tools/RightSidebar.tsx
index a4bdbced7e..d66d30c442 100644
--- a/frontend/editor/src/core/components/tools/RightSidebar.tsx
+++ b/frontend/editor/src/core/components/tools/RightSidebar.tsx
@@ -108,7 +108,7 @@ export default function RightSidebar() {
 
   const activeTool: ToolRegistryEntry | null =
     inToolView && selectedToolKey
-      ? (toolRegistry[selectedToolKey as ToolId] ?? null)
+      ? (toolRegistry[selectedToolKey] ?? null)
       : null;
 
   const expandedWidth = "18.5rem";
@@ -131,7 +131,7 @@ export default function RightSidebar() {
     const items: Array<{ id: ToolId; tool: ToolRegistryEntry }> = [];
     collapsedQuickSection.subcategories.forEach((sc: SubcategoryGroup) =>
       sc.tools.forEach((entry) =>
-        items.push({ id: entry.id as ToolId, tool: entry.tool }),
+        items.push({ id: entry.id, tool: entry.tool }),
       ),
     );
     return items;
diff --git a/frontend/editor/src/core/components/tools/ToolRenderer.tsx b/frontend/editor/src/core/components/tools/ToolRenderer.tsx
index 1429231ab7..4c99afbca2 100644
--- a/frontend/editor/src/core/components/tools/ToolRenderer.tsx
+++ b/frontend/editor/src/core/components/tools/ToolRenderer.tsx
@@ -19,9 +19,7 @@ const ToolRenderer = ({
   // Get the tool from context (instead of direct hook call)
   const { toolRegistry } = useToolWorkflow();
   const selectedTool =
-    selectedToolKey in toolRegistry
-      ? toolRegistry[selectedToolKey as ToolId]
-      : undefined;
+    selectedToolKey in toolRegistry ? toolRegistry[selectedToolKey] : undefined;
 
   // Handle tools that only work in workbenches (read, multiTool)
   if (selectedTool && !selectedTool.component && selectedTool.workbench) {
diff --git a/frontend/editor/src/core/components/tools/addPageNumbers/PageNumberPreview.tsx b/frontend/editor/src/core/components/tools/addPageNumbers/PageNumberPreview.tsx
index 6e35b286a9..9991c4b849 100644
--- a/frontend/editor/src/core/components/tools/addPageNumbers/PageNumberPreview.tsx
+++ b/frontend/editor/src/core/components/tools/addPageNumbers/PageNumberPreview.tsx
@@ -261,12 +261,7 @@ export default function PageNumberPreview({
                   variant="tertiary"
                   key={idx}
                   className={`${styles.gridTile} ${selected || hoverTile === idx ? styles.gridTileSelected : ""} ${hoverTile === idx ? styles.gridTileHovered : ""}`}
-                  onClick={() =>
-                    onParameterChange(
-                      "position",
-                      idx as AddPageNumbersParameters["position"],
-                    )
-                  }
+                  onClick={() => onParameterChange("position", idx)}
                   onMouseEnter={() => setHoverTile(idx)}
                   onMouseLeave={() => setHoverTile(null)}
                   style={{
diff --git a/frontend/editor/src/core/components/tools/addWatermark/WatermarkStyleSettings.tsx b/frontend/editor/src/core/components/tools/addWatermark/WatermarkStyleSettings.tsx
index 1d9dad2995..c9ce1ca1bd 100644
--- a/frontend/editor/src/core/components/tools/addWatermark/WatermarkStyleSettings.tsx
+++ b/frontend/editor/src/core/components/tools/addWatermark/WatermarkStyleSettings.tsx
@@ -36,9 +36,7 @@ const WatermarkStyleSettings = ({
           onChange={(value) =>
             onParameterChange(
               "rotation",
-              typeof value === "number"
-                ? value
-                : parseInt(value as string, 10) || 0,
+              typeof value === "number" ? value : parseInt(value, 10) || 0,
             )
           }
           min={-360}
@@ -55,9 +53,7 @@ const WatermarkStyleSettings = ({
           onChange={(value) =>
             onParameterChange(
               "opacity",
-              typeof value === "number"
-                ? value
-                : parseInt(value as string, 10) || 50,
+              typeof value === "number" ? value : parseInt(value, 10) || 50,
             )
           }
           min={0}
@@ -77,9 +73,7 @@ const WatermarkStyleSettings = ({
           onChange={(value) =>
             onParameterChange(
               "widthSpacer",
-              typeof value === "number"
-                ? value
-                : parseInt(value as string, 10) || 50,
+              typeof value === "number" ? value : parseInt(value, 10) || 50,
             )
           }
           min={0}
@@ -96,9 +90,7 @@ const WatermarkStyleSettings = ({
           onChange={(value) =>
             onParameterChange(
               "heightSpacer",
-              typeof value === "number"
-                ? value
-                : parseInt(value as string, 10) || 50,
+              typeof value === "number" ? value : parseInt(value, 10) || 50,
             )
           }
           min={0}
diff --git a/frontend/editor/src/core/components/tools/adjustPageScale/AdjustPageScaleSettings.tsx b/frontend/editor/src/core/components/tools/adjustPageScale/AdjustPageScaleSettings.tsx
index aeb874b58e..e2bf0a8466 100644
--- a/frontend/editor/src/core/components/tools/adjustPageScale/AdjustPageScaleSettings.tsx
+++ b/frontend/editor/src/core/components/tools/adjustPageScale/AdjustPageScaleSettings.tsx
@@ -103,9 +103,7 @@ const AdjustPageScaleSettings = ({
       <SegmentedControl
         aria-label={t("adjustPageScale.orientation.label", "Page orientation")}
         value={parameters.orientation}
-        onChange={(value) =>
-          onParameterChange("orientation", value as Orientation)
-        }
+        onChange={(value) => onParameterChange("orientation", value)}
         options={orientationOptions}
         fullWidth
       />
diff --git a/frontend/editor/src/core/components/tools/certSign/WetSignatureInput.tsx b/frontend/editor/src/core/components/tools/certSign/WetSignatureInput.tsx
index f87fda19fe..af1913baa7 100644
--- a/frontend/editor/src/core/components/tools/certSign/WetSignatureInput.tsx
+++ b/frontend/editor/src/core/components/tools/certSign/WetSignatureInput.tsx
@@ -238,9 +238,7 @@ const WetSignatureInput = ({
         <SegmentedControl
           value={signatureType}
           fullWidth
-          onChange={(value) =>
-            handleSignatureTypeChange(value as SignatureType)
-          }
+          onChange={(value) => handleSignatureTypeChange(value)}
           options={[
             { label: t("sign.type.canvas", "Draw"), value: "canvas", disabled },
             { label: t("sign.type.image", "Upload"), value: "image", disabled },
diff --git a/frontend/editor/src/core/components/tools/compare/ComparePixelWorkbenchView.tsx b/frontend/editor/src/core/components/tools/compare/ComparePixelWorkbenchView.tsx
index d45ccd75a0..35b3a7e0f4 100644
--- a/frontend/editor/src/core/components/tools/compare/ComparePixelWorkbenchView.tsx
+++ b/frontend/editor/src/core/components/tools/compare/ComparePixelWorkbenchView.tsx
@@ -170,7 +170,7 @@ const ComparePixelWorkbenchView = ({
         <SegmentedControl
           size="sm"
           value={viewMode}
-          onChange={(value) => setViewMode(value as PixelViewMode)}
+          onChange={(value) => setViewMode(value)}
           options={[
             {
               value: "side-by-side",
diff --git a/frontend/editor/src/core/components/tools/compare/CompareWorkbenchView.tsx b/frontend/editor/src/core/components/tools/compare/CompareWorkbenchView.tsx
index 1df0f1c14a..5470e3ac8c 100644
--- a/frontend/editor/src/core/components/tools/compare/CompareWorkbenchView.tsx
+++ b/frontend/editor/src/core/components/tools/compare/CompareWorkbenchView.tsx
@@ -28,7 +28,6 @@ import {
   updateToastProgress,
   dismissToast,
 } from "@app/components/toast";
-import type { ToastLocation } from "@app/components/toast/types";
 
 interface CompareWorkbenchViewProps {
   data: CompareWorkbenchData | null;
@@ -323,7 +322,7 @@ const CompareTextWorkbenchView = ({ data }: CompareTextWorkbenchViewProps) => {
             "At least one of these PDFs are very large, scrolling won't be smooth until the rendering is complete",
           ),
           body: `${countsText} ${t("compare.rendering.pagesRendered", "pages rendered")}`,
-          location: "bottom-right" as ToastLocation,
+          location: "bottom-right",
           isPersistentPopup: true,
           durationMs: 0,
           expandable: false,
@@ -337,7 +336,7 @@ const CompareTextWorkbenchView = ({ data }: CompareTextWorkbenchViewProps) => {
             "At least one of these PDFs are very large, scrolling won't be smooth until the rendering is complete",
           ),
           body: `${countsText} ${t("compare.rendering.pagesRendered", "pages rendered")}`,
-          location: "bottom-right" as ToastLocation,
+          location: "bottom-right",
           isPersistentPopup: true,
           alertType: "neutral", // ensure it stays neutral until completion
         });
@@ -452,7 +451,7 @@ const CompareTextWorkbenchView = ({ data }: CompareTextWorkbenchViewProps) => {
             "compare.rendering.pageNotReadyBody",
             "Some pages are still rendering. Navigation will snap once they are ready.",
           ),
-          location: "bottom-right" as ToastLocation,
+          location: "bottom-right",
           isPersistentPopup: false,
           durationMs: 2500,
         });
diff --git a/frontend/editor/src/core/components/tools/compare/compare.ts b/frontend/editor/src/core/components/tools/compare/compare.ts
index 30d0c42304..b157745307 100644
--- a/frontend/editor/src/core/components/tools/compare/compare.ts
+++ b/frontend/editor/src/core/components/tools/compare/compare.ts
@@ -186,7 +186,7 @@ export const getFileFromSelection = (
 ): StirlingFile | null => {
   if (explicit) return explicit;
   if (!fileId) return null;
-  return (selectors.getFile(fileId) as StirlingFile | undefined | null) ?? null;
+  return selectors.getFile(fileId) ?? null;
 };
 
 export const getStubFromSelection = (
diff --git a/frontend/editor/src/core/components/tools/compare/hooks/useCompareChangeNavigation.ts b/frontend/editor/src/core/components/tools/compare/hooks/useCompareChangeNavigation.ts
index d7d8e95635..e56187f5f2 100644
--- a/frontend/editor/src/core/components/tools/compare/hooks/useCompareChangeNavigation.ts
+++ b/frontend/editor/src/core/components/tools/compare/hooks/useCompareChangeNavigation.ts
@@ -79,7 +79,7 @@ export const useCompareChangeNavigation = (
         const inner = anchor.closest(
           ".compare-diff-page__inner",
         ) as HTMLElement | null;
-        const topPercent = parseFloat((anchor as HTMLElement).style.top || "0");
+        const topPercent = parseFloat(anchor.style.top || "0");
         if (pageEl && inner && !Number.isNaN(topPercent)) {
           const innerRect = inner.getBoundingClientRect();
           const innerHeight = Math.max(1, innerRect.height);
@@ -156,9 +156,7 @@ export const useCompareChangeNavigation = (
             ".compare-diff-page",
           ) as HTMLElement | null;
           const pageNumAttr = pageEl?.getAttribute("data-page-number");
-          const topPercent = parseFloat(
-            (anchor as HTMLElement).style.top || "0",
-          );
+          const topPercent = parseFloat(anchor.style.top || "0");
           if (pageNumAttr) {
             const peerPageEl = peer.querySelector(
               `.compare-diff-page[data-page-number="${pageNumAttr}"]`,
diff --git a/frontend/editor/src/core/components/tools/compare/hooks/useComparePanZoom.ts b/frontend/editor/src/core/components/tools/compare/hooks/useComparePanZoom.ts
index bac47de952..d44c55e1ec 100644
--- a/frontend/editor/src/core/components/tools/compare/hooks/useComparePanZoom.ts
+++ b/frontend/editor/src/core/components/tools/compare/hooks/useComparePanZoom.ts
@@ -323,7 +323,7 @@ export const useComparePanZoom = ({
       const pages = getPagesForPane(pane);
       const rotation = pages[0]?.rotation ?? 0;
       const normalized = ((rotation % 360) + 360) % 360;
-      return normalized as 0 | 90 | 180 | 270 | number;
+      return normalized;
     },
     [getPagesForPane],
   );
@@ -656,7 +656,7 @@ export const useComparePanZoom = ({
       };
       edgeOverscrollRef.current[pane] = 0;
       lastActivePaneRef.current = pane;
-      (container as HTMLDivElement).style.cursor = "grabbing";
+      container.style.cursor = "grabbing";
     },
     [isPanMode, baseZoom, comparisonZoom, basePan, comparisonPan],
   );
@@ -700,11 +700,7 @@ export const useComparePanZoom = ({
         : comparisonScrollRef.current;
     if (sourceEl) {
       const zoom = drag.source === "base" ? baseZoom : comparisonZoom;
-      (sourceEl as HTMLDivElement).style.cursor = isPanMode
-        ? zoom > 1
-          ? "grab"
-          : "auto"
-        : "";
+      sourceEl.style.cursor = isPanMode ? (zoom > 1 ? "grab" : "auto") : "";
     }
     panDragRef.current.active = false;
     panDragRef.current.source = null;
diff --git a/frontend/editor/src/core/components/tools/compare/hooks/useCompareWorkbenchBarButtons.tsx b/frontend/editor/src/core/components/tools/compare/hooks/useCompareWorkbenchBarButtons.tsx
index 3ddbbbf3da..076ac877d5 100644
--- a/frontend/editor/src/core/components/tools/compare/hooks/useCompareWorkbenchBarButtons.tsx
+++ b/frontend/editor/src/core/components/tools/compare/hooks/useCompareWorkbenchBarButtons.tsx
@@ -3,7 +3,6 @@ import type React from "react";
 import { useTranslation } from "react-i18next";
 import LocalIcon from "@app/components/shared/LocalIcon";
 import { alert } from "@app/components/toast";
-import type { ToastLocation } from "@app/components/toast/types";
 import type { WorkbenchBarButtonWithAction } from "@app/hooks/useWorkbenchBarButtons";
 import { useIsMobile } from "@app/hooks/useIsMobile";
 
@@ -179,7 +178,7 @@ export const useCompareWorkbenchBarButtons = ({
                   "Tip: Arrow Up/Down scroll both panes when unlinked is off.",
                 ),
                 durationMs: 5000,
-                location: "bottom-center" as ToastLocation,
+                location: "bottom-center",
                 expandable: false,
               });
             }
diff --git a/frontend/editor/src/core/components/tools/fullscreen/DetailedToolItem.stories.tsx b/frontend/editor/src/core/components/tools/fullscreen/DetailedToolItem.stories.tsx
index cd443e248a..901824aaf6 100644
--- a/frontend/editor/src/core/components/tools/fullscreen/DetailedToolItem.stories.tsx
+++ b/frontend/editor/src/core/components/tools/fullscreen/DetailedToolItem.stories.tsx
@@ -94,10 +94,10 @@ type Story = StoryObj<typeof meta>;
 
 /** An available tool rendered in its default, unselected state. */
 export const Default: Story = {
-  render: () => <ToolItemDemo toolId={"split" as ToolId} />,
+  render: () => <ToolItemDemo toolId={"split"} />,
 };
 
 /** The active tool in the panel — highlighted selected state. */
 export const Selected: Story = {
-  render: () => <ToolItemDemo toolId={"split" as ToolId} isSelected />,
+  render: () => <ToolItemDemo toolId={"split"} isSelected />,
 };
diff --git a/frontend/editor/src/core/components/tools/overlayPdfs/OverlayPdfsSettings.tsx b/frontend/editor/src/core/components/tools/overlayPdfs/OverlayPdfsSettings.tsx
index e7246bb4e3..8df455182e 100644
--- a/frontend/editor/src/core/components/tools/overlayPdfs/OverlayPdfsSettings.tsx
+++ b/frontend/editor/src/core/components/tools/overlayPdfs/OverlayPdfsSettings.tsx
@@ -137,7 +137,7 @@ export default function OverlayPdfsSettings({
         <SegmentedControl
           value={String(parameters.overlayPosition)}
           onChange={(v) =>
-            onParameterChange("overlayPosition", (v === "1" ? 1 : 0) as 0 | 1)
+            onParameterChange("overlayPosition", v === "1" ? 1 : 0)
           }
           options={[
             {
diff --git a/frontend/editor/src/core/components/tools/pdfTextEditor/PdfTextEditorSidebar.tsx b/frontend/editor/src/core/components/tools/pdfTextEditor/PdfTextEditorSidebar.tsx
index 1892aaa7f3..a0ce9fc362 100644
--- a/frontend/editor/src/core/components/tools/pdfTextEditor/PdfTextEditorSidebar.tsx
+++ b/frontend/editor/src/core/components/tools/pdfTextEditor/PdfTextEditorSidebar.tsx
@@ -279,9 +279,7 @@ const PdfTextEditorSidebar = ({ data }: PdfTextEditorSidebarProps) => {
                   </Text>
                   <SegmentedControl
                     value={externalGroupingMode}
-                    onChange={(value) =>
-                      handleModeChangeRequest(value as GroupingMode)
-                    }
+                    onChange={(value) => handleModeChangeRequest(value)}
                     options={[
                       {
                         label: t("pdfTextEditor.groupingMode.auto", "Auto"),
diff --git a/frontend/editor/src/core/components/tools/shared/ReviewToolStep.tsx b/frontend/editor/src/core/components/tools/shared/ReviewToolStep.tsx
index 7918bac7ca..ef596c2a0d 100644
--- a/frontend/editor/src/core/components/tools/shared/ReviewToolStep.tsx
+++ b/frontend/editor/src/core/components/tools/shared/ReviewToolStep.tsx
@@ -12,7 +12,6 @@ import { useFileActionTerminology } from "@app/hooks/useFileActionTerminology";
 import { useFileActionIcons } from "@app/hooks/useFileActionIcons";
 import { saveOperationResults } from "@app/services/operationResultsSaveService";
 import { useFileActions, useFileSelectors } from "@app/contexts/FileContext";
-import { FileId } from "@app/types/fileContext";
 import i18n from "@app/i18n";
 
 export interface ReviewToolStepProps<TParams = unknown> {
@@ -65,11 +64,11 @@ function ReviewStepContent<TParams = unknown>({
         downloadFilename: operation.downloadFilename || "download",
         downloadLocalPath: operation.downloadLocalPath,
         outputFileIds: operation.outputFileIds,
-        getFile: (fileId) => selectors.getFile(fileId as FileId),
-        getStub: (fileId) => selectors.getStirlingFileStub(fileId as FileId),
+        getFile: (fileId) => selectors.getFile(fileId),
+        getStub: (fileId) => selectors.getStirlingFileStub(fileId),
         markSaved: (fileId, savedPath) => {
-          const stub = selectors.getStirlingFileStub(fileId as FileId);
-          fileActions.updateStirlingFileStub(fileId as FileId, {
+          const stub = selectors.getStirlingFileStub(fileId);
+          fileActions.updateStirlingFileStub(fileId, {
             localFilePath: stub?.localFilePath ?? savedPath,
             isDirty: false,
           });
diff --git a/frontend/editor/src/core/components/tools/showJS/utils.ts b/frontend/editor/src/core/components/tools/showJS/utils.ts
index e946ec271e..7c6530c21b 100644
--- a/frontend/editor/src/core/components/tools/showJS/utils.ts
+++ b/frontend/editor/src/core/components/tools/showJS/utils.ts
@@ -186,7 +186,7 @@ export function tokenizeToLines(
     }
 
     if (isStringDelimiter) {
-      startString(ch as '"' | "'" | "`");
+      startString(ch);
       continue;
     }
 
@@ -312,7 +312,7 @@ export function computeBlocks(
       continue;
     }
     if (isStringDelimiter) {
-      startString(ch as '"' | "'" | "`");
+      startString(ch);
       continue;
     }
     if (isOpenBrace) {
diff --git a/frontend/editor/src/core/components/tools/sign/MobileSignatureModal.test.tsx b/frontend/editor/src/core/components/tools/sign/MobileSignatureModal.test.tsx
index c8607d55c4..4f68e7c68c 100644
--- a/frontend/editor/src/core/components/tools/sign/MobileSignatureModal.test.tsx
+++ b/frontend/editor/src/core/components/tools/sign/MobileSignatureModal.test.tsx
@@ -52,9 +52,9 @@ function primeSession(
   mockedApi.post.mockResolvedValue({
     status: 200,
     data: SESSION_INFO,
-  } as never);
-  mockedApi.delete.mockResolvedValue({ status: 200 } as never);
-  mockedApi.get.mockImplementation(((url: string, config?: unknown) => {
+  });
+  mockedApi.delete.mockResolvedValue({ status: 200 });
+  mockedApi.get.mockImplementation((url: string, config?: unknown) => {
     if (url.includes("/files/")) {
       return Promise.resolve({ status: 200, data: { files } } as never);
     }
@@ -70,7 +70,7 @@ function primeSession(
       } as never);
     }
     return Promise.reject(new Error(`unexpected GET ${url}`));
-  }) as never);
+  });
 }
 
 function renderModal(
diff --git a/frontend/editor/src/core/components/tools/sign/SignSettings.tsx b/frontend/editor/src/core/components/tools/sign/SignSettings.tsx
index 4aa9f8ffd3..1d78343c79 100644
--- a/frontend/editor/src/core/components/tools/sign/SignSettings.tsx
+++ b/frontend/editor/src/core/components/tools/sign/SignSettings.tsx
@@ -519,7 +519,7 @@ const SignSettings = ({
       return;
     }
     const nextSource = allowedSignatureSources.includes(
-      parameters.signatureType as SignatureSource,
+      parameters.signatureType,
     )
       ? (parameters.signatureType as SignatureSource)
       : effectiveDefaultSource;
@@ -1282,9 +1282,7 @@ const SignSettings = ({
           <SegmentedControl
             value={signatureSource}
             fullWidth
-            onChange={(value) =>
-              handleSignatureSourceChange(value as SignatureSource)
-            }
+            onChange={(value) => handleSignatureSourceChange(value)}
             options={sourceOptions}
           />
         )}
diff --git a/frontend/editor/src/core/components/tools/toolPicker/ToolButton.tsx b/frontend/editor/src/core/components/tools/toolPicker/ToolButton.tsx
index 4792fd721a..8daf2cb019 100644
--- a/frontend/editor/src/core/components/tools/toolPicker/ToolButton.tsx
+++ b/frontend/editor/src/core/components/tools/toolPicker/ToolButton.tsx
@@ -74,7 +74,7 @@ const ToolButton: React.FC<ToolButtonProps> = ({
   const { hotkeys } = useHotkeys();
   const binding = hotkeys[id];
   const { getToolNavigation } = useToolNavigation();
-  const fav = isFavorite(id as ToolId);
+  const fav = isFavorite(id);
 
   // Check if this tool will route to SaaS backend (desktop only)
   const rawEndpoint = tool.operationConfig?.endpoint;
@@ -308,7 +308,7 @@ const ToolButton: React.FC<ToolButtonProps> = ({
     hasStars && !visuallyUnavailable ? (
       <FavoriteStar
         isFavorite={fav}
-        onToggle={() => toggleFavorite(id as ToolId)}
+        onToggle={() => toggleFavorite(id)}
         className="tool-button-star"
         size="xs"
       />
diff --git a/frontend/editor/src/core/components/tools/validateSignature/ValidateSignatureResults.tsx b/frontend/editor/src/core/components/tools/validateSignature/ValidateSignatureResults.tsx
index 22020ac6dc..23a9d9e949 100644
--- a/frontend/editor/src/core/components/tools/validateSignature/ValidateSignatureResults.tsx
+++ b/frontend/editor/src/core/components/tools/validateSignature/ValidateSignatureResults.tsx
@@ -294,7 +294,7 @@ const ValidateSignatureResults = ({
         </Text>
         <SegmentedControl
           value={selectedType}
-          onChange={(v) => setSelectedType(v as "pdf" | "csv" | "json")}
+          onChange={(v) => setSelectedType(v)}
           options={downloadTypeOptions}
         />
         <Button
diff --git a/frontend/editor/src/core/contexts/file/classificationToolRace.test.ts b/frontend/editor/src/core/contexts/file/classificationToolRace.test.ts
index faf6501a0c..21efc2234f 100644
--- a/frontend/editor/src/core/contexts/file/classificationToolRace.test.ts
+++ b/frontend/editor/src/core/contexts/file/classificationToolRace.test.ts
@@ -35,10 +35,7 @@ function stateWith(...stubs: StirlingFileStub[]): FileContextState {
   return {
     files: {
       ids: stubs.map((s) => s.id),
-      byId: Object.fromEntries(stubs.map((s) => [s.id, s])) as Record<
-        FileId,
-        StirlingFileStub
-      >,
+      byId: Object.fromEntries(stubs.map((s) => [s.id, s])),
     },
     pinnedFiles: new Set<FileId>(),
     ui: {
@@ -153,7 +150,7 @@ describe("classification landing vs a manually-run tool", () => {
         versionNumber: 7,
         thumbnailUrl: "blob:thumb",
         isPinned: true,
-      } as Partial<StirlingFileStub>),
+      }),
     );
 
     s = fileContextReducer(s, classify("out"));
diff --git a/frontend/editor/src/core/data/usePrototypeToolRegistry.tsx b/frontend/editor/src/core/data/usePrototypeToolRegistry.tsx
index 6a3279196e..b4da797a14 100644
--- a/frontend/editor/src/core/data/usePrototypeToolRegistry.tsx
+++ b/frontend/editor/src/core/data/usePrototypeToolRegistry.tsx
@@ -11,5 +11,5 @@ import { type PrototypeToolRegistry } from "@app/data/toolsTaxonomy";
 
 // Empty hook that returns an empty registry (overridden in the prototypes overlay).
 export function usePrototypeToolRegistry(): PrototypeToolRegistry {
-  return useMemo(() => ({}) as PrototypeToolRegistry, []);
+  return useMemo(() => ({}), []);
 }
diff --git a/frontend/editor/src/core/hooks/tools/addPassword/useAddPasswordOperation.test.ts b/frontend/editor/src/core/hooks/tools/addPassword/useAddPasswordOperation.test.ts
index 28e8e1baa6..364f2ec3de 100644
--- a/frontend/editor/src/core/hooks/tools/addPassword/useAddPasswordOperation.test.ts
+++ b/frontend/editor/src/core/hooks/tools/addPassword/useAddPasswordOperation.test.ts
@@ -152,7 +152,7 @@ describe("addPassword mappers", () => {
     // undefined: the settings UI calls keyLength.toString() on it.
     const restored = addPasswordFromApiParams({
       password: "user-pw",
-    } as never);
+    });
     expect(restored.keyLength).toBe(128);
   });
 
diff --git a/frontend/editor/src/core/hooks/tools/autoRotate/useAutoRotateOperation.ts b/frontend/editor/src/core/hooks/tools/autoRotate/useAutoRotateOperation.ts
index fde4ae1eca..02c81a9483 100644
--- a/frontend/editor/src/core/hooks/tools/autoRotate/useAutoRotateOperation.ts
+++ b/frontend/editor/src/core/hooks/tools/autoRotate/useAutoRotateOperation.ts
@@ -22,7 +22,6 @@ import type {
 } from "@app/hooks/tools/shared/toolApiMapping";
 import {
   AutoRotateParameters,
-  AutoRotateDetectionMode,
   defaultParameters,
   validateAutoRotateParameters,
 } from "@app/hooks/tools/autoRotate/useAutoRotateParameters";
@@ -50,7 +49,7 @@ export const autoRotateToApiParams = (
 export const autoRotateFromApiParams = (
   apiParams: AutoRotateApiParams,
 ): Partial<AutoRotateParameters> => ({
-  detectionMode: apiParams.detectionMode as AutoRotateDetectionMode,
+  detectionMode: apiParams.detectionMode,
   confidenceThreshold: apiParams.confidenceThreshold,
   inferUndetected: apiParams.inferUndetected,
 });
diff --git a/frontend/editor/src/core/hooks/tools/automate/useAutomateOperation.ts b/frontend/editor/src/core/hooks/tools/automate/useAutomateOperation.ts
index d1d6436fa9..4a96532321 100644
--- a/frontend/editor/src/core/hooks/tools/automate/useAutomateOperation.ts
+++ b/frontend/editor/src/core/hooks/tools/automate/useAutomateOperation.ts
@@ -24,7 +24,7 @@ export function useAutomateOperation() {
 
       // Execute the automation sequence and return the final results
       const finalResults = await executeAutomationSequence(
-        params.automationConfig!,
+        params.automationConfig,
         files,
         toolRegistry,
         (stepIndex: number, operationName: string) => {
diff --git a/frontend/editor/src/core/hooks/tools/compare/operationUtils.ts b/frontend/editor/src/core/hooks/tools/compare/operationUtils.ts
index 832eaba560..78d651c6d9 100644
--- a/frontend/editor/src/core/hooks/tools/compare/operationUtils.ts
+++ b/frontend/editor/src/core/hooks/tools/compare/operationUtils.ts
@@ -358,7 +358,7 @@ export const extractContentFromPdf = async (
           .trim();
 
       const isParagraphBreak = (curr: TextItem, prev: TextItem | null) => {
-        const hasHardBreak = "hasEOL" in curr && (curr as TextItem).hasEOL;
+        const hasHardBreak = "hasEOL" in curr && curr.hasEOL;
         if (hasHardBreak) return true;
         if (!prev) return false;
         const prevY = prev.transform[5];
@@ -624,7 +624,7 @@ export const extractContentFromPdf = async (
           paragraphBuffer = appendWord(paragraphBuffer, normalizedWord);
         }
 
-        if (isParagraphBreak(item as TextItem, prevItem)) {
+        if (isParagraphBreak(item, prevItem)) {
           if (paragraphBuffer.trim().length > 0) {
             paragraphs.push({
               page: pageIndex,
@@ -641,7 +641,7 @@ export const extractContentFromPdf = async (
           });
           paragraphIndex += 1;
         }
-        prevItem = item as TextItem;
+        prevItem = item;
       }
 
       if (paragraphBuffer.trim().length > 0) {
diff --git a/frontend/editor/src/core/hooks/tools/compare/useCompareOperation.ts b/frontend/editor/src/core/hooks/tools/compare/useCompareOperation.ts
index 3a40d9b699..73667946eb 100644
--- a/frontend/editor/src/core/hooks/tools/compare/useCompareOperation.ts
+++ b/frontend/editor/src/core/hooks/tools/compare/useCompareOperation.ts
@@ -28,7 +28,6 @@ import {
   filterTokensForDiff,
 } from "@app/hooks/tools/compare/operationUtils";
 import { alert, dismissToast } from "@app/components/toast";
-import type { ToastLocation } from "@app/components/toast/types";
 import CompareWorkerCtor from "@app/workers/compareWorker?worker";
 const LONG_RUNNING_PAGE_THRESHOLD = 2000;
 
@@ -406,7 +405,7 @@ export const useCompareOperation = (): CompareOperationHook => {
               "compare.longJob.body",
               "These PDFs together exceed 2,000 pages. Processing can take several minutes.",
             ),
-            location: "bottom-right" as ToastLocation,
+            location: "bottom-right",
             isPersistentPopup: true,
             expandable: false,
           });
@@ -435,7 +434,7 @@ export const useCompareOperation = (): CompareOperationHook => {
               "compare.earlyDissimilarity.body",
               "We're seeing very few similarities so far. You can stop the comparison if these aren't related documents.",
             ),
-            location: "bottom-right" as ToastLocation,
+            location: "bottom-right",
             isPersistentPopup: true,
             expandable: false,
             buttonText: t(
@@ -635,7 +634,7 @@ export const useCompareOperation = (): CompareOperationHook => {
           alertType: "warning",
           title: t("compare.error.title", "Comparison failed"),
           body: resolvedMessage,
-          location: "bottom-right" as ToastLocation,
+          location: "bottom-right",
         });
       } finally {
         const duration = performance.now() - operationStart;
diff --git a/frontend/editor/src/core/hooks/tools/convert/useConvertOperation.ts b/frontend/editor/src/core/hooks/tools/convert/useConvertOperation.ts
index 554946cce7..4d54b438f4 100644
--- a/frontend/editor/src/core/hooks/tools/convert/useConvertOperation.ts
+++ b/frontend/editor/src/core/hooks/tools/convert/useConvertOperation.ts
@@ -383,7 +383,7 @@ export const convertToApiParams = (
   formData.forEach((value, key) => {
     if (typeof value === "string") body[key] = value;
   });
-  return body as unknown as ToolApiParams[ToolEndpoint];
+  return body;
 };
 
 /**
@@ -406,12 +406,6 @@ type ConvertOptionReaders = {
   ) => Partial<ConvertParameters>;
 };
 
-/** The reader shape collapsed for the runtime dispatch, where the endpoint is only a string. */
-type ConvertOptionReader = (
-  body: Record<string, string | undefined>,
-  toExtension: string,
-) => Partial<ConvertParameters>;
-
 // The stored values are strings; these read one back into the typed shape ConvertParameters expects,
 // validating an enum against its allowed set (asEnum) rather than blind-casting an arbitrary string.
 const asFlag = (value: string | undefined): boolean => value === "true";
@@ -583,12 +577,9 @@ export const convertFromApiParams = (
   const fromExtension = body.fromExtension ?? "";
   const toExtension = body.toExtension ?? "";
   const endpoint = convertEndpointFor(fromExtension, toExtension);
-  // Each reader reads only its own endpoint's fields; the runtime endpoint is just a string, so the
-  // precise per-endpoint type is recovered with one widening cast here (every reader accepts a
-  // superset string record).
-  const readOptions = endpoint
-    ? (CONVERT_OPTION_READERS[endpoint] as ConvertOptionReader | undefined)
-    : undefined;
+  // Each reader reads only its own endpoint's fields; the runtime endpoint is just a string, so
+  // readOptions is looked up per-endpoint (undefined when the pair has no reader).
+  const readOptions = endpoint ? CONVERT_OPTION_READERS[endpoint] : undefined;
   return {
     fromExtension,
     toExtension,
diff --git a/frontend/editor/src/core/hooks/tools/shared/toolAutomation.ts b/frontend/editor/src/core/hooks/tools/shared/toolAutomation.ts
index a9368ccdb7..ad9466534c 100644
--- a/frontend/editor/src/core/hooks/tools/shared/toolAutomation.ts
+++ b/frontend/editor/src/core/hooks/tools/shared/toolAutomation.ts
@@ -534,7 +534,7 @@ export function deserializeToolStep(
   const params: ErasedToolParams = {
     ...(config?.defaultParameters ?? {}),
     ...mapped,
-  } as ErasedToolParams;
+  };
   // Validate against the generated endpoint set instead of casting the matched string.
   const operation =
     resolveEndpoint(config, params) ??
diff --git a/frontend/editor/src/core/hooks/tools/shared/toolOperationDescriptor.ts b/frontend/editor/src/core/hooks/tools/shared/toolOperationDescriptor.ts
index 3c8f78d1b8..337909fc7b 100644
--- a/frontend/editor/src/core/hooks/tools/shared/toolOperationDescriptor.ts
+++ b/frontend/editor/src/core/hooks/tools/shared/toolOperationDescriptor.ts
@@ -50,10 +50,9 @@ export function describeToolOperation<
     // A dynamic tool's mapper is typed against the union; narrow to this endpoint (sound - the
     // runtime mapper produces this endpoint's model).
     toApi: (params) => toApiParams(params) as ToolApiParams[E],
-    fromApi: (api) =>
-      ({
-        ...defaultParameters,
-        ...fromApiParams(api as ToolApiParams[CE]),
-      }) as TParams,
+    fromApi: (api) => ({
+      ...defaultParameters,
+      ...fromApiParams(api),
+    }),
   };
 }
diff --git a/frontend/editor/src/core/hooks/tools/shared/toolOperationTypes.ts b/frontend/editor/src/core/hooks/tools/shared/toolOperationTypes.ts
index d01d897002..6cbe97428b 100644
--- a/frontend/editor/src/core/hooks/tools/shared/toolOperationTypes.ts
+++ b/frontend/editor/src/core/hooks/tools/shared/toolOperationTypes.ts
@@ -284,7 +284,7 @@ export function defineSingleFileTool<
   return {
     ...config,
     toolType: ToolType.singleFile,
-  } as SingleFileToolOperationConfig<TParams, TEndpoint>;
+  };
 }
 
 /** Multi-file counterpart of {@link defineSingleFileTool}. */
@@ -300,7 +300,7 @@ export function defineMultiFileTool<
   return {
     ...config,
     toolType: ToolType.multiFile,
-  } as MultiFileToolOperationConfig<TParams, TEndpoint>;
+  };
 }
 
 /**
diff --git a/frontend/editor/src/core/hooks/tools/shared/useToolOperation.ts b/frontend/editor/src/core/hooks/tools/shared/useToolOperation.ts
index 822d281c57..d0ad5f8521 100644
--- a/frontend/editor/src/core/hooks/tools/shared/useToolOperation.ts
+++ b/frontend/editor/src/core/hooks/tools/shared/useToolOperation.ts
@@ -227,10 +227,7 @@ export const useToolOperation = <TParams>(
             : [];
         }
       };
-      window.addEventListener(
-        FILE_EVENTS.markError,
-        errorListener as EventListener,
-      );
+      window.addEventListener(FILE_EVENTS.markError, errorListener);
 
       try {
         let processedFiles: File[];
@@ -619,10 +616,7 @@ export const useToolOperation = <TParams>(
         actions.setError(errorMessage);
         actions.setStatus("");
       } finally {
-        window.removeEventListener(
-          FILE_EVENTS.markError,
-          errorListener as EventListener,
-        );
+        window.removeEventListener(FILE_EVENTS.markError, errorListener);
         actions.setLoading(false);
         actions.setProgress(null);
       }
diff --git a/frontend/editor/src/core/hooks/tools/useFavoriteToolItems.ts b/frontend/editor/src/core/hooks/tools/useFavoriteToolItems.ts
index b1295110db..20a091bcea 100644
--- a/frontend/editor/src/core/hooks/tools/useFavoriteToolItems.ts
+++ b/frontend/editor/src/core/hooks/tools/useFavoriteToolItems.ts
@@ -9,8 +9,8 @@ export function useFavoriteToolItems(
   return useMemo(() => {
     return favoriteTools
       .map((toolId) => {
-        const tool = toolRegistry[toolId as ToolId];
-        return tool ? { id: toolId as ToolId, tool } : null;
+        const tool = toolRegistry[toolId];
+        return tool ? { id: toolId, tool } : null;
       })
       .filter((x): x is { id: ToolId; tool: ToolRegistryEntry } => x !== null)
       .filter(
diff --git a/frontend/editor/src/core/hooks/tools/validateSignature/utils/signatureStatus.test.ts b/frontend/editor/src/core/hooks/tools/validateSignature/utils/signatureStatus.test.ts
index e7fca7622a..e1c621686e 100644
--- a/frontend/editor/src/core/hooks/tools/validateSignature/utils/signatureStatus.test.ts
+++ b/frontend/editor/src/core/hooks/tools/validateSignature/utils/signatureStatus.test.ts
@@ -95,10 +95,7 @@ describe("computeSignatureStatus - trust surfacing", () => {
   });
 
   test("backend error message -> Invalid", () => {
-    const status = computeSignatureStatus(
-      sig({ errorMessage: "boom" } as Partial<SignatureValidationSignature>),
-      t,
-    );
+    const status = computeSignatureStatus(sig({ errorMessage: "boom" }), t);
     expect(status.kind).toBe("invalid");
     expect(status.details).toContain("boom");
   });
diff --git a/frontend/editor/src/core/i18n.ts b/frontend/editor/src/core/i18n.ts
index 839652658c..e69488c4e5 100644
--- a/frontend/editor/src/core/i18n.ts
+++ b/frontend/editor/src/core/i18n.ts
@@ -102,7 +102,7 @@ function getCurrentSourcePriority(): LanguageSource {
   const sourceStr = localStorage.getItem(I18N_STORAGE_KEYS.LANGUAGE_SOURCE);
   const sourceNum = sourceStr ? parseInt(sourceStr, 10) : null;
   return sourceNum !== null && !isNaN(sourceNum)
-    ? (sourceNum as LanguageSource)
+    ? sourceNum
     : LanguageSource.Fallback;
 }
 
diff --git a/frontend/editor/src/core/setupTests.ts b/frontend/editor/src/core/setupTests.ts
index d01c3cb589..a0a347a660 100644
--- a/frontend/editor/src/core/setupTests.ts
+++ b/frontend/editor/src/core/setupTests.ts
@@ -118,7 +118,7 @@ Object.defineProperty(globalThis, "crypto", {
       }
       return array;
     }),
-  } as unknown as Crypto,
+  },
   writable: true,
   configurable: true,
 });
diff --git a/frontend/editor/src/core/tests/stubbed/settings.spec.ts b/frontend/editor/src/core/tests/stubbed/settings.spec.ts
index a9b0bbaa17..1b0bfd3be7 100644
--- a/frontend/editor/src/core/tests/stubbed/settings.spec.ts
+++ b/frontend/editor/src/core/tests/stubbed/settings.spec.ts
@@ -144,15 +144,11 @@ test.describe("Settings dialog", () => {
       const origReplace = window.history.replaceState.bind(window.history);
       window.history.pushState = function (...args) {
         w.__historyOps.push++;
-        return origPush(
-          ...(args as Parameters<typeof window.history.pushState>),
-        );
+        return origPush(...args);
       };
       window.history.replaceState = function (...args) {
         w.__historyOps.replace++;
-        return origReplace(
-          ...(args as Parameters<typeof window.history.replaceState>),
-        );
+        return origReplace(...args);
       };
     });
 
diff --git a/frontend/editor/src/core/tools/Compare.tsx b/frontend/editor/src/core/tools/Compare.tsx
index 0b2a8d5171..6242e12dab 100644
--- a/frontend/editor/src/core/tools/Compare.tsx
+++ b/frontend/editor/src/core/tools/Compare.tsx
@@ -175,8 +175,8 @@ const Compare = (props: BaseToolProps) => {
   );
 
   useEffect(() => {
-    const baseFileId = params.baseFileId as FileId | null;
-    const comparisonFileId = params.comparisonFileId as FileId | null;
+    const baseFileId = params.baseFileId;
+    const comparisonFileId = params.comparisonFileId;
 
     if (!baseFileId || !comparisonFileId) {
       lastProcessedAtRef.current = null;
@@ -437,9 +437,7 @@ const Compare = (props: BaseToolProps) => {
                       : "Select the edited PDF",
                   )
             }
-            excludeIds={
-              otherSlot ? [otherSlot.stirlingFile.fileId as string] : []
-            }
+            excludeIds={otherSlot ? [otherSlot.stirlingFile.fileId] : []}
             disabled={isDisabled}
             onSelect={(result: FileSelectorResult) => {
               if (role === "base") setBaseSlot(result);
diff --git a/frontend/editor/src/core/tools/SharedSign.tsx b/frontend/editor/src/core/tools/SharedSign.tsx
index 5131db40c3..3a335f392a 100644
--- a/frontend/editor/src/core/tools/SharedSign.tsx
+++ b/frontend/editor/src/core/tools/SharedSign.tsx
@@ -129,9 +129,9 @@ const SharedSign = (_props: BaseToolProps) => {
 
   const onItemClick = (item: SessionItem) => {
     if (item.itemType === "signRequest") {
-      void controller.openSignRequest(item as SignRequestSummary);
+      void controller.openSignRequest(item);
     } else {
-      void controller.openSession(item as SessionSummary);
+      void controller.openSession(item);
     }
   };
 
@@ -247,7 +247,7 @@ const SharedSign = (_props: BaseToolProps) => {
       <SegmentedControl
         fullWidth
         value={tab}
-        onChange={(value) => changeTab(value as Tab)}
+        onChange={(value) => changeTab(value)}
         options={[
           { label: t("sharedSign.tab.active", "Active"), value: "active" },
           {
diff --git a/frontend/editor/src/core/tools/annotate/AnnotationPanel.tsx b/frontend/editor/src/core/tools/annotate/AnnotationPanel.tsx
index 6986f4d7e4..0535af1519 100644
--- a/frontend/editor/src/core/tools/annotate/AnnotationPanel.tsx
+++ b/frontend/editor/src/core/tools/annotate/AnnotationPanel.tsx
@@ -891,7 +891,7 @@ export function AnnotationPanel(props: AnnotationPanelProps) {
           ) {
             annotationApiRef?.current?.updateAnnotation?.(
               selectedAnn.object.pageIndex ?? 0,
-              selectedAnn.object.id as string,
+              selectedAnn.object.id,
               {
                 opacity: opacity / 100,
               },
@@ -906,7 +906,7 @@ export function AnnotationPanel(props: AnnotationPanelProps) {
           if (selectedAnn?.object?.id && selectedAnn.object?.type === 10) {
             annotationApiRef?.current?.updateAnnotation?.(
               selectedAnn.object.pageIndex ?? 0,
-              selectedAnn.object.id as string,
+              selectedAnn.object.id,
               {
                 opacity: opacity / 100,
               },
@@ -921,7 +921,7 @@ export function AnnotationPanel(props: AnnotationPanelProps) {
           if (selectedAnn?.object?.id && selectedAnn.object?.type === 12) {
             annotationApiRef?.current?.updateAnnotation?.(
               selectedAnn.object.pageIndex ?? 0,
-              selectedAnn.object.id as string,
+              selectedAnn.object.id,
               {
                 opacity: opacity / 100,
               },
@@ -936,7 +936,7 @@ export function AnnotationPanel(props: AnnotationPanelProps) {
           if (selectedAnn?.object?.id && selectedAnn.object?.type === 11) {
             annotationApiRef?.current?.updateAnnotation?.(
               selectedAnn.object.pageIndex ?? 0,
-              selectedAnn.object.id as string,
+              selectedAnn.object.id,
               {
                 opacity: opacity / 100,
               },
@@ -1017,7 +1017,7 @@ export function AnnotationPanel(props: AnnotationPanelProps) {
           if (selectedAnn?.object?.id) {
             annotationApiRef?.current?.updateAnnotation?.(
               selectedAnn.object.pageIndex ?? 0,
-              selectedAnn.object.id as string,
+              selectedAnn.object.id,
               {
                 color,
               },
@@ -1032,7 +1032,7 @@ export function AnnotationPanel(props: AnnotationPanelProps) {
           if (selectedAnn?.object?.id) {
             annotationApiRef?.current?.updateAnnotation?.(
               selectedAnn.object.pageIndex ?? 0,
-              selectedAnn.object.id as string,
+              selectedAnn.object.id,
               {
                 color,
               },
@@ -1047,7 +1047,7 @@ export function AnnotationPanel(props: AnnotationPanelProps) {
           if (selectedAnn?.object?.id) {
             annotationApiRef?.current?.updateAnnotation?.(
               selectedAnn.object.pageIndex ?? 0,
-              selectedAnn.object.id as string,
+              selectedAnn.object.id,
               {
                 color,
               },
@@ -1140,7 +1140,7 @@ export function AnnotationPanel(props: AnnotationPanelProps) {
           if (selectedAnn?.object?.id) {
             annotationApiRef?.current?.updateAnnotation?.(
               selectedAnn.object.pageIndex ?? 0,
-              selectedAnn.object.id as string,
+              selectedAnn.object.id,
               {
                 strokeColor: color,
                 color: selectedAnn.object?.color ?? shapeFillColor,
@@ -1163,7 +1163,7 @@ export function AnnotationPanel(props: AnnotationPanelProps) {
           if (selectedAnn?.object?.id) {
             annotationApiRef?.current?.updateAnnotation?.(
               selectedAnn.object.pageIndex ?? 0,
-              selectedAnn.object.id as string,
+              selectedAnn.object.id,
               {
                 color,
                 strokeColor:
diff --git a/frontend/editor/src/core/tools/formFill/FormFieldOverlay.tsx b/frontend/editor/src/core/tools/formFill/FormFieldOverlay.tsx
index 331180ad6f..40f9cdf603 100644
--- a/frontend/editor/src/core/tools/formFill/FormFieldOverlay.tsx
+++ b/frontend/editor/src/core/tools/formFill/FormFieldOverlay.tsx
@@ -146,7 +146,7 @@ function executePdfJs(
     change: "",
     rc: true,
     willCommit: false,
-    target: null as null,
+    target: null,
   };
 
   try {
diff --git a/frontend/editor/src/core/tools/formFill/FormFillContext.tsx b/frontend/editor/src/core/tools/formFill/FormFillContext.tsx
index 97fde82901..8bccb51400 100644
--- a/frontend/editor/src/core/tools/formFill/FormFillContext.tsx
+++ b/frontend/editor/src/core/tools/formFill/FormFillContext.tsx
@@ -377,7 +377,7 @@ export function FormFillProvider({
   const [providerMode, setProviderModeState] = useState<"pdflib" | "pdfbox">(
     initialMode,
   );
-  const providerModeRef = useRef(initialMode as "pdflib" | "pdfbox");
+  const providerModeRef = useRef(initialMode);
   providerModeRef.current = providerMode;
   const provider =
     providerProp ??
diff --git a/frontend/editor/src/core/tools/formFill/providers/PdfiumFormProvider.ts b/frontend/editor/src/core/tools/formFill/providers/PdfiumFormProvider.ts
index 27dc19595a..87d18c3f2f 100644
--- a/frontend/editor/src/core/tools/formFill/providers/PdfiumFormProvider.ts
+++ b/frontend/editor/src/core/tools/formFill/providers/PdfiumFormProvider.ts
@@ -22,12 +22,7 @@ import type {
   ButtonAction,
 } from "@app/tools/formFill/types";
 import type { IFormDataProvider } from "@app/tools/formFill/providers/types";
-import type {
-  PDFDict,
-  PDFString,
-  PDFHexString,
-  PDFName,
-} from "@cantoo/pdf-lib";
+import type { PDFDict } from "@cantoo/pdf-lib";
 
 interface PDFAcroField {
   dict: PDFDict;
@@ -317,7 +312,7 @@ export class PdfiumFormProvider implements IFormDataProvider {
 
       const decodeText = (obj: unknown): string => {
         if (obj instanceof PDFString || obj instanceof PDFHexString)
-          return (obj as PDFString | PDFHexString).decodeText();
+          return obj.decodeText();
         return String(obj ?? "");
       };
 
@@ -410,28 +405,27 @@ export class PdfiumFormProvider implements IFormDataProvider {
 
       const decodeText = (obj: unknown): string | null => {
         if (obj instanceof PDFString || obj instanceof PDFHexString)
-          return (obj as PDFString | PDFHexString).decodeText();
+          return obj.decodeText();
         if (obj instanceof PDFName)
-          return (obj as PDFName).asString() ?? String(obj).replace(/^\//, "");
+          return obj.asString() ?? String(obj).replace(/^\//, "");
         return null;
       };
 
       const parseActionDict = (aObj: unknown): ButtonAction | null => {
         if (!(aObj instanceof PDFDict)) return null;
         // @cantoo/pdf-lib ships without individual .d.ts files so instanceof can't narrow `unknown`
-        const a = aObj as PDFDict;
+        const a = aObj;
         const sObj = a.lookup(PDFName.of("S"));
         if (!(sObj instanceof PDFName)) return null;
         const actionType: string =
-          (sObj as PDFName).asString() ?? String(sObj).replace(/^\//, "");
+          sObj.asString() ?? String(sObj).replace(/^\//, "");
 
         switch (actionType) {
           case "Named": {
             const nObj = a.lookup(PDFName.of("N"));
             const name =
               nObj instanceof PDFName
-                ? ((nObj as PDFName).asString() ??
-                  String(nObj).replace(/^\//, ""))
+                ? (nObj.asString() ?? String(nObj).replace(/^\//, ""))
                 : "";
             return { type: "named", namedAction: name };
           }
diff --git a/frontend/editor/src/core/ui/Checkbox.tsx b/frontend/editor/src/core/ui/Checkbox.tsx
index 778bd13b01..eb7a6263b7 100644
--- a/frontend/editor/src/core/ui/Checkbox.tsx
+++ b/frontend/editor/src/core/ui/Checkbox.tsx
@@ -33,9 +33,7 @@ export const Checkbox = forwardRef<HTMLInputElement, CheckboxProps>(
         <input
           ref={(el) => {
             if (typeof ref === "function") ref(el);
-            else if (ref)
-              (ref as React.MutableRefObject<HTMLInputElement | null>).current =
-                el;
+            else if (ref) ref.current = el;
             if (el) el.indeterminate = !!indeterminate;
           }}
           type="checkbox"
diff --git a/frontend/editor/src/core/utils/bulkselection/parseSelection.ts b/frontend/editor/src/core/utils/bulkselection/parseSelection.ts
index 1705056055..ed8b356651 100644
--- a/frontend/editor/src/core/utils/bulkselection/parseSelection.ts
+++ b/frontend/editor/src/core/utils/bulkselection/parseSelection.ts
@@ -107,7 +107,7 @@ function parseCsvFallback(input: string, max: number): Set<number> {
 }
 
 function clampToRange(v: number, min: number, max: number): number {
-  if (!Number.isFinite(v)) return NaN as unknown as number;
+  if (!Number.isFinite(v)) return NaN;
   return Math.min(Math.max(v, min), max);
 }
 
@@ -281,7 +281,7 @@ class ExpressionParser {
     if (!word) return null;
     const lower = word.toLowerCase();
     if (lower === "even" || lower === "odd") {
-      return lower as "even" | "odd";
+      return lower;
     }
     // Not a keyword; rewind
     this.idx = start;
diff --git a/frontend/editor/src/desktop/hooks/useEndpointConfig.ts b/frontend/editor/src/desktop/hooks/useEndpointConfig.ts
index 9a80435095..490a793df0 100644
--- a/frontend/editor/src/desktop/hooks/useEndpointConfig.ts
+++ b/frontend/editor/src/desktop/hooks/useEndpointConfig.ts
@@ -371,7 +371,10 @@ export function useMultipleEndpointsEnabled(endpoints: string[]): {
         }
       } else {
         setError(message);
-        const fallbackStatus = endpoints.reduce(
+        const fallbackStatus = endpoints.reduce<{
+          status: Record<string, boolean>;
+          details: Record<string, EndpointAvailabilityDetails>;
+        }>(
           (acc, endpointName) => {
             const fallbackDetail: EndpointAvailabilityDetails = {
               enabled: false,
@@ -382,8 +385,8 @@ export function useMultipleEndpointsEnabled(endpoints: string[]): {
             return acc;
           },
           {
-            status: {} as Record<string, boolean>,
-            details: {} as Record<string, EndpointAvailabilityDetails>,
+            status: {},
+            details: {},
           },
         );
 
diff --git a/frontend/editor/src/portal/auth/saasSupabase.ts b/frontend/editor/src/portal/auth/saasSupabase.ts
index ff3ad71b8b..1005d63a63 100644
--- a/frontend/editor/src/portal/auth/saasSupabase.ts
+++ b/frontend/editor/src/portal/auth/saasSupabase.ts
@@ -38,7 +38,7 @@ let configured = false;
 export function ensureSaasSupabase() {
   if (!isSaasSupabaseConfigured) return null;
   if (!configured) {
-    configureSupabase({ url: url as string, key: key as string });
+    configureSupabase({ url: url, key: key });
     configured = true;
   }
   return getSupabaseClient();
diff --git a/frontend/editor/src/portal/components/docs/EndpointReferenceSection.tsx b/frontend/editor/src/portal/components/docs/EndpointReferenceSection.tsx
index 55b1c47f51..0a54de7658 100644
--- a/frontend/editor/src/portal/components/docs/EndpointReferenceSection.tsx
+++ b/frontend/editor/src/portal/components/docs/EndpointReferenceSection.tsx
@@ -1,6 +1,6 @@
 import { useMemo, useState } from "react";
 import { useTranslation } from "react-i18next";
-import { MethodBadge, Tabs, type HttpMethod, type TabItem } from "@app/ui";
+import { MethodBadge, Tabs, type TabItem } from "@app/ui";
 import { VERTICALS, ALL_ENDPOINTS } from "@portal/data/endpoints";
 import { DocsSection } from "@portal/components/docs/DocsSection";
 import "@portal/theme/surface.css";
@@ -61,7 +61,7 @@ export function EndpointReferenceSection() {
             </div>
             {v.endpoints.map((e) => (
               <div key={e.endpoint} className="portal-docs__endpoint-row">
-                <MethodBadge method={"POST" as HttpMethod} />
+                <MethodBadge method={"POST"} />
                 <code className="portal-docs__endpoint-path">{e.endpoint}</code>
                 <span className="portal-docs__endpoint-name">{e.name}</span>
                 <span className="portal-docs__endpoint-fields">
diff --git a/frontend/editor/src/portal/components/pipelines/PipelineStepSettings.test.tsx b/frontend/editor/src/portal/components/pipelines/PipelineStepSettings.test.tsx
index 0b15b7233a..0850499a99 100644
--- a/frontend/editor/src/portal/components/pipelines/PipelineStepSettings.test.tsx
+++ b/frontend/editor/src/portal/components/pipelines/PipelineStepSettings.test.tsx
@@ -275,8 +275,7 @@ describe("PipelineStepSettings: every tool's settings render in the portal", ()
       const Settings = entry.automationSettings as ComponentType<
         ToolAutomationSettingsProps<ErasedToolParams>
       >;
-      const params = (entry.operationConfig?.defaultParameters ??
-        {}) as ErasedToolParams;
+      const params = entry.operationConfig?.defaultParameters ?? {};
 
       const caught: { error: Error | null } = { error: null };
       // The sentinel sibling commits only once the lazy Settings actually renders, so we wait for a
diff --git a/frontend/editor/src/portal/components/policies/PolicySetupWizard.tsx b/frontend/editor/src/portal/components/policies/PolicySetupWizard.tsx
index b50e2efe12..cccdb36e40 100644
--- a/frontend/editor/src/portal/components/policies/PolicySetupWizard.tsx
+++ b/frontend/editor/src/portal/components/policies/PolicySetupWizard.tsx
@@ -457,7 +457,7 @@ function PolicySetupWizardBody({
         variant="underline"
         ariaLabel={t("portal.policies.wizard.tabs.ariaLabel")}
         activeKey={step}
-        onChange={(k) => setStep(k as Step)}
+        onChange={(k) => setStep(k)}
         items={[
           { key: "workflow", label: t("portal.policies.wizard.tabs.workflow") },
           { key: "settings", label: t("portal.policies.wizard.tabs.settings") },
diff --git a/frontend/editor/src/portal/components/processor-flow/useFlowParticles.ts b/frontend/editor/src/portal/components/processor-flow/useFlowParticles.ts
index 65fc6cc9ad..a32ea76a4d 100644
--- a/frontend/editor/src/portal/components/processor-flow/useFlowParticles.ts
+++ b/frontend/editor/src/portal/components/processor-flow/useFlowParticles.ts
@@ -134,10 +134,7 @@ export function useFlowParticles({
         for (let i = 0; i < meanInterval.length; i++) {
           if (!Number.isFinite(meanInterval[i]) || !g.srcs[i]) continue;
           if (now >= nextEmit[i] && particles.length < MAX_PARTICLES) {
-            const c = document.createElementNS(
-              NS,
-              "circle",
-            ) as SVGCircleElement;
+            const c = document.createElementNS(NS, "circle");
             c.setAttribute("r", "2.5");
             c.setAttribute("opacity", "0.75");
             c.style.fill = "var(--c-primary)";
diff --git a/frontend/editor/src/portal/mocks/handlers/policies.ts b/frontend/editor/src/portal/mocks/handlers/policies.ts
index 1bfc435d4c..ce6c041ae9 100644
--- a/frontend/editor/src/portal/mocks/handlers/policies.ts
+++ b/frontend/editor/src/portal/mocks/handlers/policies.ts
@@ -35,7 +35,7 @@ function nextId(categoryId: string): string {
 }
 
 function categoryId(wire: WirePolicy): string {
-  return (wire.output?.options?.categoryId as string | undefined) ?? "";
+  return wire.output?.options?.categoryId ?? "";
 }
 
 export const policiesHandlers = [
diff --git a/frontend/editor/src/portal/mocks/handlers/procurementSaas.ts b/frontend/editor/src/portal/mocks/handlers/procurementSaas.ts
index fe75827c2d..2f5246ce8d 100644
--- a/frontend/editor/src/portal/mocks/handlers/procurementSaas.ts
+++ b/frontend/editor/src/portal/mocks/handlers/procurementSaas.ts
@@ -256,7 +256,7 @@ export const procurementSaasHandlers = [
       stage: "quote",
       licensed: true,
       latestQuote: quote,
-    } as never;
+    };
     return HttpResponse.json(quote);
   }),
   http.post(`${SAAS}/api/v1/procurement/trial/extend`, () => {
diff --git a/frontend/editor/src/portal/queries/adapters.ts b/frontend/editor/src/portal/queries/adapters.ts
index 083e396bad..3cb091d8cd 100644
--- a/frontend/editor/src/portal/queries/adapters.ts
+++ b/frontend/editor/src/portal/queries/adapters.ts
@@ -11,6 +11,6 @@ export function toAsyncState<T>(query: UseQueryResult<T>): AsyncState<T> {
   return {
     data: query.data ?? null,
     loading: query.isPending,
-    error: (query.error as Error | null) ?? null,
+    error: query.error ?? null,
   };
 }
diff --git a/frontend/editor/src/portal/setupTests.ts b/frontend/editor/src/portal/setupTests.ts
index 7de4f9f309..22d95aa1ab 100644
--- a/frontend/editor/src/portal/setupTests.ts
+++ b/frontend/editor/src/portal/setupTests.ts
@@ -50,7 +50,7 @@ global.IntersectionObserver = vi.fn().mockImplementation(() => ({
   observe: vi.fn(),
   unobserve: vi.fn(),
   disconnect: vi.fn(),
-})) as unknown as typeof IntersectionObserver;
+}));
 
 Object.defineProperty(window, "matchMedia", {
   writable: true,
diff --git a/frontend/editor/src/proprietary/auth/springAuthClient.test.ts b/frontend/editor/src/proprietary/auth/springAuthClient.test.ts
index 54fed2028d..13f5c6d651 100644
--- a/frontend/editor/src/proprietary/auth/springAuthClient.test.ts
+++ b/frontend/editor/src/proprietary/auth/springAuthClient.test.ts
@@ -12,11 +12,7 @@ import apiClient from "@app/services/apiClient";
 // + oauthNavigation seam, so springAuth routes through the mocks below.
 import "@app/auth/configureSpringAuth";
 import { allowConsole, expectConsole } from "@app/tests/failOnConsole";
-import {
-  AxiosError,
-  type AxiosResponse,
-  type InternalAxiosRequestConfig,
-} from "axios";
+import { AxiosError, type InternalAxiosRequestConfig } from "axios";
 
 // Mock apiClient
 vi.mock("@app/services/apiClient");
@@ -59,7 +55,7 @@ describe("SpringAuthClient", () => {
       vi.mocked(apiClient.get).mockResolvedValueOnce({
         status: 200,
         data: { user: mockUser },
-      } as unknown as AxiosResponse);
+      });
 
       const result = await springAuth.getSession();
 
@@ -176,7 +172,7 @@ describe("SpringAuthClient", () => {
             expires_in: 3600,
           },
         },
-      } as unknown as AxiosResponse);
+      });
 
       // Spy on window.dispatchEvent
       const dispatchEventSpy = vi.spyOn(window, "dispatchEvent");
@@ -235,7 +231,7 @@ describe("SpringAuthClient", () => {
       vi.mocked(apiClient.post).mockResolvedValueOnce({
         status: 200,
         data: {},
-      } as unknown as AxiosResponse);
+      });
 
       const result = await springAuth.signOut();
 
@@ -288,7 +284,7 @@ describe("SpringAuthClient", () => {
             expires_in: 3600,
           },
         },
-      } as unknown as AxiosResponse);
+      });
 
       const result = await springAuth.refreshSession();
 
@@ -375,7 +371,7 @@ describe("SpringAuthClient", () => {
         expect(isSafePostLoginRedirect("")).toBe(false);
         expect(isSafePostLoginRedirect(null)).toBe(false);
         expect(isSafePostLoginRedirect(undefined)).toBe(false);
-        expect(isSafePostLoginRedirect(42 as unknown)).toBe(false);
+        expect(isSafePostLoginRedirect(42)).toBe(false);
       });
 
       it("rejects protocol-relative and absolute URLs (open-redirect guard)", () => {
diff --git a/frontend/editor/src/proprietary/auth/supabase/UseSession.tsx b/frontend/editor/src/proprietary/auth/supabase/UseSession.tsx
index 6bcc6b501e..385f3f4e35 100644
--- a/frontend/editor/src/proprietary/auth/supabase/UseSession.tsx
+++ b/frontend/editor/src/proprietary/auth/supabase/UseSession.tsx
@@ -46,7 +46,7 @@ function mapUser(user: SbUser): AuthUser {
       "",
     role: readRole(user),
     is_anonymous: user.is_anonymous,
-    app_metadata: user.app_metadata as Record<string, unknown>,
+    app_metadata: user.app_metadata,
   };
 }
 
diff --git a/frontend/editor/src/proprietary/components/policies/policyRunSettles.test.ts b/frontend/editor/src/proprietary/components/policies/policyRunSettles.test.ts
index fdce331821..c3c6be7137 100644
--- a/frontend/editor/src/proprietary/components/policies/policyRunSettles.test.ts
+++ b/frontend/editor/src/proprietary/components/policies/policyRunSettles.test.ts
@@ -7,20 +7,19 @@ import type { PolicyRunRecord } from "@app/components/policies/policyRunStore";
  * effect used to skip those runs entirely, so `imported` never flipped and the
  * file's badge + blocking overlay spun forever - on every engine.
  */
-const run = (overrides: Partial<PolicyRunRecord> = {}): PolicyRunRecord =>
-  ({
-    runId: "r",
-    categoryId: "security",
-    fileId: "f",
-    fileName: "f.pdf",
-    fileSize: 1,
-    target: "saas",
-    status: "COMPLETED",
-    outputs: [],
-    error: null,
-    startedAt: 0,
-    ...overrides,
-  }) as PolicyRunRecord;
+const run = (overrides: Partial<PolicyRunRecord> = {}): PolicyRunRecord => ({
+  runId: "r",
+  categoryId: "security",
+  fileId: "f",
+  fileName: "f.pdf",
+  fileSize: 1,
+  target: "saas",
+  status: "COMPLETED",
+  outputs: [],
+  error: null,
+  startedAt: 0,
+  ...overrides,
+});
 
 describe("finishedWithNothingToDeliver", () => {
   it("settles a completed run that produced no output", () => {
diff --git a/frontend/editor/src/proprietary/components/policies/useClientSideClassification.ts b/frontend/editor/src/proprietary/components/policies/useClientSideClassification.ts
index 64fd849d87..ede1768b2a 100644
--- a/frontend/editor/src/proprietary/components/policies/useClientSideClassification.ts
+++ b/frontend/editor/src/proprietary/components/policies/useClientSideClassification.ts
@@ -99,7 +99,7 @@ export function useClientSideClassification(): void {
           if (claimed.current.has(key)) continue;
           claimed.current.add(key);
           const verdict = await classifyStub(
-            stub.id as FileId,
+            stub.id,
             stub.name,
             stub.size ?? 0,
           );
@@ -108,11 +108,11 @@ export function useClientSideClassification(): void {
           if (verdict == null) continue;
           // Deliver unconditionally - a re-render must never discard a computed
           // (and already metered) result. Writes are idempotent.
-          updateStirlingFileStub(stub.id as FileId, {
+          updateStirlingFileStub(stub.id, {
             classificationLabels: verdict.labels,
             classificationConfidence: verdict.confidence,
           });
-          const ok = await fileStorage.updateFileMetadata(stub.id as FileId, {
+          const ok = await fileStorage.updateFileMetadata(stub.id, {
             classificationLabels: verdict.labels,
             classificationConfidence: verdict.confidence,
           });
diff --git a/frontend/editor/src/proprietary/components/policies/usePolicyAutoRun.ts b/frontend/editor/src/proprietary/components/policies/usePolicyAutoRun.ts
index 936fef8119..0638b1432c 100644
--- a/frontend/editor/src/proprietary/components/policies/usePolicyAutoRun.ts
+++ b/frontend/editor/src/proprietary/components/policies/usePolicyAutoRun.ts
@@ -768,7 +768,7 @@ async function importOutputs(
     // Mark the outputs handled BEFORE adding them (belt-and-suspenders session
     // guard on top of derivedFromTool) so the auto-run never enforces the policy
     // on its own output — that would version endlessly in a loop.
-    for (const s of categorized) markHandled(s.id as string);
+    for (const s of categorized) markHandled(s.id);
     deliveredIds = categorized.map((s) => s.id as string);
     if (ctx.parentStub) {
       // Input is in the active workspace: version it in place, silently — the
@@ -799,7 +799,7 @@ async function importOutputs(
       derivedFromTool: true,
     });
     // Belt-and-suspenders session guard on top of derivedFromTool.
-    for (const f of added) markHandled(f.fileId as string);
+    for (const f of added) markHandled(f.fileId);
     deliveredIds = added.map((f) => f.fileId as string);
     // Mark each new-file output as tool-derived (the versioned path gets this from the
     // CONSUME_FILES reducer; the addFiles path doesn't). This is the real loop guard: the dispatch
diff --git a/frontend/editor/src/proprietary/components/shared/FileSidebarGroupControls.tsx b/frontend/editor/src/proprietary/components/shared/FileSidebarGroupControls.tsx
index 41d1358594..1b37a13bb7 100644
--- a/frontend/editor/src/proprietary/components/shared/FileSidebarGroupControls.tsx
+++ b/frontend/editor/src/proprietary/components/shared/FileSidebarGroupControls.tsx
@@ -46,7 +46,7 @@ export function FileSidebarGroupControls({
       const ids = new Set<string>();
       for (const key of category.labelKeys) {
         for (const stub of byLabel.get(key)?.stubs ?? []) {
-          ids.add(stub.id as string);
+          ids.add(stub.id);
         }
       }
       counts.set(category.id, ids.size);
diff --git a/frontend/editor/src/proprietary/components/shared/InviteMembersModal.tsx b/frontend/editor/src/proprietary/components/shared/InviteMembersModal.tsx
index e57f60395f..063fb1c4ef 100644
--- a/frontend/editor/src/proprietary/components/shared/InviteMembersModal.tsx
+++ b/frontend/editor/src/proprietary/components/shared/InviteMembersModal.tsx
@@ -460,7 +460,7 @@ export default function InviteMembersModal({
               <SegmentedControl
                 value={inviteMode}
                 onChange={(value) => {
-                  setInviteMode(value as "email" | "direct" | "link");
+                  setInviteMode(value);
                   setGeneratedInviteLink(null);
                 }}
                 options={[
diff --git a/frontend/editor/src/proprietary/components/shared/UpgradeBanner.tsx b/frontend/editor/src/proprietary/components/shared/UpgradeBanner.tsx
index 365c64a030..fdb92dc271 100644
--- a/frontend/editor/src/proprietary/components/shared/UpgradeBanner.tsx
+++ b/frontend/editor/src/proprietary/components/shared/UpgradeBanner.tsx
@@ -67,15 +67,9 @@ const UpgradeBanner: React.FC = () => {
       }
     };
 
-    window.addEventListener(
-      UPGRADE_BANNER_TEST_EVENT,
-      handleTestEvent as EventListener,
-    );
+    window.addEventListener(UPGRADE_BANNER_TEST_EVENT, handleTestEvent);
     return () => {
-      window.removeEventListener(
-        UPGRADE_BANNER_TEST_EVENT,
-        handleTestEvent as EventListener,
-      );
+      window.removeEventListener(UPGRADE_BANNER_TEST_EVENT, handleTestEvent);
     };
   }, [isDev]);
 
diff --git a/frontend/editor/src/proprietary/components/shared/config/LoginLandingSetting.test.tsx b/frontend/editor/src/proprietary/components/shared/config/LoginLandingSetting.test.tsx
index 31d45c0d45..b9caf6ba8d 100644
--- a/frontend/editor/src/proprietary/components/shared/config/LoginLandingSetting.test.tsx
+++ b/frontend/editor/src/proprietary/components/shared/config/LoginLandingSetting.test.tsx
@@ -3,7 +3,7 @@ import { render, screen, waitFor } from "@testing-library/react";
 import { MantineProvider } from "@mantine/core";
 
 const h = vi.hoisted(() => ({
-  prefs: { loginLandingView: "processor" as "processor" | "editor" },
+  prefs: { loginLandingView: "processor" },
   update: vi.fn(),
   get: vi.fn(),
 }));
diff --git a/frontend/editor/src/proprietary/components/shared/config/configSections/AdminConnectionsSection.tsx b/frontend/editor/src/proprietary/components/shared/config/configSections/AdminConnectionsSection.tsx
index f788551551..b993889e52 100644
--- a/frontend/editor/src/proprietary/components/shared/config/configSections/AdminConnectionsSection.tsx
+++ b/frontend/editor/src/proprietary/components/shared/config/configSections/AdminConnectionsSection.tsx
@@ -518,11 +518,11 @@ export default function AdminConnectionsSection() {
     updatedSettings: Record<string, unknown>,
   ) => {
     if (provider.id === "smtp") {
-      setSettings({ ...settings, mail: updatedSettings as MailSettings });
+      setSettings({ ...settings, mail: updatedSettings });
     } else if (provider.id === "telegram") {
       setSettings({
         ...settings,
-        telegram: updatedSettings as TelegramSettingsData,
+        telegram: updatedSettings,
       });
     } else if (provider.id === "googledrive") {
       const gd = updatedSettings as GoogleDriveSettings;
@@ -534,7 +534,7 @@ export default function AdminConnectionsSection() {
         googleDriveAppId: gd.appId,
       });
     } else if (provider.id === "saml2") {
-      setSettings({ ...settings, saml2: updatedSettings as Saml2Settings });
+      setSettings({ ...settings, saml2: updatedSettings });
     } else if (provider.id === "oauth2-generic") {
       const generic = updatedSettings as OAuth2GenericSettings;
       setSettings({ ...settings, oauth2: { ...settings.oauth2, ...generic } });
diff --git a/frontend/editor/src/proprietary/components/shared/config/configSections/AdminUsageSection.tsx b/frontend/editor/src/proprietary/components/shared/config/configSections/AdminUsageSection.tsx
index 6b46789bdd..d0a0a1b2e9 100644
--- a/frontend/editor/src/proprietary/components/shared/config/configSections/AdminUsageSection.tsx
+++ b/frontend/editor/src/proprietary/components/shared/config/configSections/AdminUsageSection.tsx
@@ -332,9 +332,7 @@ const AdminUsageSection: React.FC = () => {
             <Group>
               <SegmentedControl
                 value={displayMode}
-                onChange={(value) =>
-                  setDisplayMode(value as "top10" | "top20" | "all")
-                }
+                onChange={(value) => setDisplayMode(value)}
                 options={[
                   {
                     value: "top10",
@@ -373,7 +371,7 @@ const AdminUsageSection: React.FC = () => {
             </Text>
             <SegmentedControl
               value={dataType}
-              onChange={(value) => setDataType(value as "all" | "api" | "ui")}
+              onChange={(value) => setDataType(value)}
               options={[
                 {
                   value: "all",
diff --git a/frontend/editor/src/proprietary/components/shared/config/configSections/audit/AuditEventsTable.tsx b/frontend/editor/src/proprietary/components/shared/config/configSections/audit/AuditEventsTable.tsx
index feca3696d4..22263596c0 100644
--- a/frontend/editor/src/proprietary/components/shared/config/configSections/audit/AuditEventsTable.tsx
+++ b/frontend/editor/src/proprietary/components/shared/config/configSections/audit/AuditEventsTable.tsx
@@ -257,11 +257,9 @@ const AuditEventsTable: React.FC<AuditEventsTableProps> = ({
                 verticalSpacing="sm"
                 withRowBorders
                 highlightOnHover
-                style={
-                  {
-                    "--table-border-color": "var(--mantine-color-gray-3)",
-                  } as React.CSSProperties
-                }
+                style={{
+                  "--table-border-color": "var(--mantine-color-gray-3)",
+                }}
               >
                 <Table.Thead>
                   <Table.Tr
diff --git a/frontend/editor/src/proprietary/components/shared/config/configSections/plan/LicenseKeySection.tsx b/frontend/editor/src/proprietary/components/shared/config/configSections/plan/LicenseKeySection.tsx
index 4b890e683a..1b19656b16 100644
--- a/frontend/editor/src/proprietary/components/shared/config/configSections/plan/LicenseKeySection.tsx
+++ b/frontend/editor/src/proprietary/components/shared/config/configSections/plan/LicenseKeySection.tsx
@@ -233,7 +233,7 @@ const LicenseKeySection: React.FC<LicenseKeySectionProps> = ({
           <SegmentedControl
             value={inputMethod}
             onChange={(value) => {
-              setInputMethod(value as "text" | "file");
+              setInputMethod(value);
               // Clear opposite input when switching
               if (value === "text") setLicenseFile(null);
               if (value === "file") setLicenseKeyInput("");
diff --git a/frontend/editor/src/proprietary/components/shared/config/configSections/usage/UsageAnalyticsTable.tsx b/frontend/editor/src/proprietary/components/shared/config/configSections/usage/UsageAnalyticsTable.tsx
index f27d5d09a3..a89cb477e3 100644
--- a/frontend/editor/src/proprietary/components/shared/config/configSections/usage/UsageAnalyticsTable.tsx
+++ b/frontend/editor/src/proprietary/components/shared/config/configSections/usage/UsageAnalyticsTable.tsx
@@ -32,11 +32,9 @@ const UsageAnalyticsTable: React.FC<UsageAnalyticsTableProps> = ({ data }) => {
           verticalSpacing="sm"
           withRowBorders
           highlightOnHover
-          style={
-            {
-              "--table-border-color": "var(--mantine-color-gray-3)",
-            } as React.CSSProperties
-          }
+          style={{
+            "--table-border-color": "var(--mantine-color-gray-3)",
+          }}
         >
           <TableThead>
             <TableTr style={{ backgroundColor: "var(--mantine-color-gray-0)" }}>
diff --git a/frontend/editor/src/proprietary/components/shared/fileSidebarGrouping.tsx b/frontend/editor/src/proprietary/components/shared/fileSidebarGrouping.tsx
index baf3d812cb..447bd19a68 100644
--- a/frontend/editor/src/proprietary/components/shared/fileSidebarGrouping.tsx
+++ b/frontend/editor/src/proprietary/components/shared/fileSidebarGrouping.tsx
@@ -20,7 +20,6 @@ import {
 } from "@app/services/fileSidebarCategories";
 import { buildLabelGroups } from "@app/components/shared/fileSidebarGroupingLogic";
 import { scheduleIdle } from "@app/utils/scheduleIdle";
-import type { FileId } from "@app/types/file";
 import type { StirlingFileStub } from "@app/types/fileContext";
 import type { FileSidebarGroup } from "@core/components/shared/fileSidebarGrouping";
 
@@ -81,7 +80,7 @@ export function useFileSidebarGroups(
           if (cancelled) return;
           attempted.current.add(attemptKey(stub));
           if (labels) {
-            const ok = await fileStorage.updateFileMetadata(stub.id as FileId, {
+            const ok = await fileStorage.updateFileMetadata(stub.id, {
               classificationLabels: labels,
             });
             if (ok) wrote = true;
diff --git a/frontend/editor/src/proprietary/components/shared/fileSidebarGroupingLogic.ts b/frontend/editor/src/proprietary/components/shared/fileSidebarGroupingLogic.ts
index 82569a9bd5..5b4b30ce33 100644
--- a/frontend/editor/src/proprietary/components/shared/fileSidebarGroupingLogic.ts
+++ b/frontend/editor/src/proprietary/components/shared/fileSidebarGroupingLogic.ts
@@ -70,7 +70,7 @@ export function buildLabelGroups(
   // Other = files in no visible group: unlabelled, or labelled only under hidden categories.
   const covered = new Set<string>();
   for (const group of visible) {
-    for (const stub of group.stubs) covered.add(stub.id as string);
+    for (const stub of group.stubs) covered.add(stub.id);
   }
   const other = stubs.filter((stub) => !covered.has(stub.id as string));
 
diff --git a/frontend/editor/src/proprietary/hooks/useFolderRunStatuses.ts b/frontend/editor/src/proprietary/hooks/useFolderRunStatuses.ts
index 031d514f5f..78f00b1fab 100644
--- a/frontend/editor/src/proprietary/hooks/useFolderRunStatuses.ts
+++ b/frontend/editor/src/proprietary/hooks/useFolderRunStatuses.ts
@@ -51,7 +51,7 @@ export function useFolderRunStatuses(
             );
             return [folder.id, deriveStatus(runs)] as const;
           } catch {
-            return [folder.id, "idle" as FolderRunStatus] as const;
+            return [folder.id, "idle"] as const;
           }
         }),
       );
diff --git a/frontend/editor/src/proprietary/policies/codec.ts b/frontend/editor/src/proprietary/policies/codec.ts
index 2ef68514e4..e6fbdf739d 100644
--- a/frontend/editor/src/proprietary/policies/codec.ts
+++ b/frontend/editor/src/proprietary/policies/codec.ts
@@ -62,10 +62,8 @@ export function fromWirePolicy(policy: WirePolicy): PolicyDecodedState {
     name: policy.name,
     enabled: policy.enabled,
     categoryId,
-    sources: Array.isArray(raw.sources) ? (raw.sources as string[]) : [],
-    scopeTypes: Array.isArray(raw.scopeTypes)
-      ? (raw.scopeTypes as string[])
-      : [],
+    sources: Array.isArray(raw.sources) ? raw.sources : [],
+    scopeTypes: Array.isArray(raw.scopeTypes) ? raw.scopeTypes : [],
     reviewerEmail: str(raw.reviewerEmail),
     fieldValues: raw.fieldValues ?? {},
     runOn: resolveRunOn(raw.runOn, categoryId),
diff --git a/frontend/editor/src/proprietary/routes/Login.test.tsx b/frontend/editor/src/proprietary/routes/Login.test.tsx
index d2cb80360f..29ae9d9d79 100644
--- a/frontend/editor/src/proprietary/routes/Login.test.tsx
+++ b/frontend/editor/src/proprietary/routes/Login.test.tsx
@@ -10,7 +10,6 @@ import { PreferencesProvider } from "@app/contexts/PreferencesContext";
 import { TestQueryProvider } from "@app/tests/utils/TestQueryProvider";
 import apiClient from "@app/services/apiClient";
 import { configureSpringAuth } from "@app/auth/config";
-import type { AxiosInstance } from "axios";
 
 // Mock i18n to return fallback text
 vi.mock("react-i18next", () => ({
@@ -137,7 +136,7 @@ describe("Login", () => {
     // The shared login hook reads getSpringAuthConfig().http; in the real app,
     // startup points that at apiClient. Mirror that here so the mocked apiClient
     // serves the login-ui-data fetch.
-    configureSpringAuth({ http: apiClient as unknown as AxiosInstance });
+    configureSpringAuth({ http: apiClient });
   });
 
   it("should render login form", async () => {
diff --git a/frontend/editor/src/proprietary/services/heuristic/heuristicEngine.ts b/frontend/editor/src/proprietary/services/heuristic/heuristicEngine.ts
index ed01b9542e..8d2f795636 100644
--- a/frontend/editor/src/proprietary/services/heuristic/heuristicEngine.ts
+++ b/frontend/editor/src/proprietary/services/heuristic/heuristicEngine.ts
@@ -387,8 +387,7 @@ export async function ensureRulesLoaded(): Promise<void> {
   if (!loadPromise) {
     loadPromise = import("@app/services/heuristic/heuristicRules.json").then(
       (mod) => {
-        const root = ((mod as { default?: RulesFile }).default ??
-          (mod as RulesFile)) as RulesFile;
+        const root = (mod as { default?: RulesFile }).default ?? mod;
         PREPARED = prepare(root.labels ?? []);
         PRIORS = loadPriors(root.priors ?? {});
       },
diff --git a/frontend/editor/src/proprietary/services/heuristic/heuristicExtractor.ts b/frontend/editor/src/proprietary/services/heuristic/heuristicExtractor.ts
index 426c1133e1..fb51b407b6 100644
--- a/frontend/editor/src/proprietary/services/heuristic/heuristicExtractor.ts
+++ b/frontend/editor/src/proprietary/services/heuristic/heuristicExtractor.ts
@@ -186,8 +186,7 @@ async function metadata(
   } catch {
     return {};
   }
-  const get = (k: string) =>
-    typeof info[k] === "string" ? (info[k] as string) : "";
+  const get = (k: string) => (typeof info[k] === "string" ? info[k] : "");
   return {
     title: get("Title"),
     author: get("Author"),
diff --git a/frontend/editor/src/proprietary/services/policyExport.ts b/frontend/editor/src/proprietary/services/policyExport.ts
index 78b747182b..91b68f8edd 100644
--- a/frontend/editor/src/proprietary/services/policyExport.ts
+++ b/frontend/editor/src/proprietary/services/policyExport.ts
@@ -222,7 +222,7 @@ export async function enforceExportPolicies(
             fileId,
             fileName: file.name,
             fileSize: file.size,
-            target: versionRun!.target,
+            target: versionRun.target,
             status: "COMPLETED",
             outputs: versionRun.outputs,
             error: null,
diff --git a/frontend/editor/src/saas/auth/UseSession.test.ts b/frontend/editor/src/saas/auth/UseSession.test.ts
index d5f8124948..94e1ffcb6a 100644
--- a/frontend/editor/src/saas/auth/UseSession.test.ts
+++ b/frontend/editor/src/saas/auth/UseSession.test.ts
@@ -17,7 +17,7 @@ function makeUser(overrides: Partial<User> = {}): User {
     user_metadata: {},
     created_at: "2026-01-01T00:00:00Z",
     ...overrides,
-  } as User;
+  };
 }
 
 describe("saas deriveDisplayName", () => {
diff --git a/frontend/editor/src/saas/components/SignupRequiredBootstrap.tsx b/frontend/editor/src/saas/components/SignupRequiredBootstrap.tsx
index b9028ce22b..7ba4230ef5 100644
--- a/frontend/editor/src/saas/components/SignupRequiredBootstrap.tsx
+++ b/frontend/editor/src/saas/components/SignupRequiredBootstrap.tsx
@@ -46,12 +46,8 @@ export default function SignupRequiredBootstrap() {
         return true;
       });
     };
-    window.addEventListener("payg:signupRequired", handler as EventListener);
-    return () =>
-      window.removeEventListener(
-        "payg:signupRequired",
-        handler as EventListener,
-      );
+    window.addEventListener("payg:signupRequired", handler);
+    return () => window.removeEventListener("payg:signupRequired", handler);
   }, []);
 
   // Map the server's gate categories to user-facing nouns. The server
diff --git a/frontend/editor/src/saas/components/shared/AppConfigModal.tsx b/frontend/editor/src/saas/components/shared/AppConfigModal.tsx
index ab93f734fb..11b8957deb 100644
--- a/frontend/editor/src/saas/components/shared/AppConfigModal.tsx
+++ b/frontend/editor/src/saas/components/shared/AppConfigModal.tsx
@@ -80,12 +80,8 @@ const AppConfigModal: React.FC<AppConfigModalProps> = ({
         setMobilePane("content");
       }
     };
-    window.addEventListener("appConfig:navigate", handler as EventListener);
-    return () =>
-      window.removeEventListener(
-        "appConfig:navigate",
-        handler as EventListener,
-      );
+    window.addEventListener("appConfig:navigate", handler);
+    return () => window.removeEventListener("appConfig:navigate", handler);
   }, []);
 
   // When the modal opens via a /settings/<section> deep link (navigateToSettings — e.g. the
@@ -122,9 +118,8 @@ const AppConfigModal: React.FC<AppConfigModalProps> = ({
         setNotice(detail.notice);
       }
     };
-    window.addEventListener("appConfig:notice", handler as EventListener);
-    return () =>
-      window.removeEventListener("appConfig:notice", handler as EventListener);
+    window.addEventListener("appConfig:notice", handler);
+    return () => window.removeEventListener("appConfig:notice", handler);
   }, []);
 
   // Full-screen overlays that live inside our React tree (e.g. the PAYG
@@ -140,9 +135,8 @@ const AppConfigModal: React.FC<AppConfigModalProps> = ({
         | undefined;
       setOverlayActive(Boolean(detail?.open));
     };
-    window.addEventListener("appConfig:overlay", handler as EventListener);
-    return () =>
-      window.removeEventListener("appConfig:overlay", handler as EventListener);
+    window.addEventListener("appConfig:overlay", handler);
+    return () => window.removeEventListener("appConfig:overlay", handler);
   }, []);
 
   const colors = useMemo(
diff --git a/frontend/editor/src/saas/components/shared/charts/StackedBarChart.tsx b/frontend/editor/src/saas/components/shared/charts/StackedBarChart.tsx
index 5f56843dae..0224b0837b 100644
--- a/frontend/editor/src/saas/components/shared/charts/StackedBarChart.tsx
+++ b/frontend/editor/src/saas/components/shared/charts/StackedBarChart.tsx
@@ -211,11 +211,9 @@ export default function StackedBarChart({
           setTooltipContent(html);
           const tooltip = tooltipRef.current;
           if (tooltip) tooltip.style.opacity = "1";
-          positionTooltip(event as unknown as MouseEvent);
+          positionTooltip(event);
         })
-        .on("mousemove", (event: MouseEvent) =>
-          positionTooltip(event as unknown as MouseEvent),
-        )
+        .on("mousemove", (event: MouseEvent) => positionTooltip(event))
         .on("mouseleave", hideTooltip);
 
       // Animate reveal of used segments (only on first load, not on re-renders)
diff --git a/frontend/editor/src/saas/components/shared/config/configSections/Overview.tsx b/frontend/editor/src/saas/components/shared/config/configSections/Overview.tsx
index 3a28152425..62f84977c1 100644
--- a/frontend/editor/src/saas/components/shared/config/configSections/Overview.tsx
+++ b/frontend/editor/src/saas/components/shared/config/configSections/Overview.tsx
@@ -562,15 +562,7 @@ const Overview: React.FC<OverviewProps> = ({ onLogoutClick }) => {
                           style={{ width: 16, height: 16 }}
                         />
                       }
-                      onClick={() =>
-                        handleOAuthUpgrade(
-                          provider.id as
-                            | "github"
-                            | "google"
-                            | "apple"
-                            | "azure",
-                        )
-                      }
+                      onClick={() => handleOAuthUpgrade(provider.id)}
                       disabled={isLoading}
                     >
                       {provider.label}
diff --git a/frontend/editor/src/saas/components/tools/sign/SignSettings.tsx b/frontend/editor/src/saas/components/tools/sign/SignSettings.tsx
index 503087cbe4..59920ab6fb 100644
--- a/frontend/editor/src/saas/components/tools/sign/SignSettings.tsx
+++ b/frontend/editor/src/saas/components/tools/sign/SignSettings.tsx
@@ -547,7 +547,7 @@ const SignSettings = ({
       return;
     }
     const nextSource = allowedSignatureSources.includes(
-      parameters.signatureType as SignatureSource,
+      parameters.signatureType,
     )
       ? (parameters.signatureType as SignatureSource)
       : effectiveDefaultSource;
@@ -1314,9 +1314,7 @@ const SignSettings = ({
           <SegmentedControl
             value={signatureSource}
             fullWidth
-            onChange={(value) =>
-              handleSignatureSourceChange(value as SignatureSource)
-            }
+            onChange={(value) => handleSignatureSourceChange(value)}
             options={sourceOptions}
           />
         )}
diff --git a/frontend/editor/src/saas/routes/OAuthConsent.tsx b/frontend/editor/src/saas/routes/OAuthConsent.tsx
index f22f13fa19..f2acc03899 100644
--- a/frontend/editor/src/saas/routes/OAuthConsent.tsx
+++ b/frontend/editor/src/saas/routes/OAuthConsent.tsx
@@ -35,9 +35,8 @@ interface AuthorizationDetails {
   };
 }
 
-const SUPABASE_URL = import.meta.env.VITE_SUPABASE_URL as string;
-const SUPABASE_KEY = import.meta.env
-  .VITE_SUPABASE_PUBLISHABLE_DEFAULT_KEY as string;
+const SUPABASE_URL = import.meta.env.VITE_SUPABASE_URL;
+const SUPABASE_KEY = import.meta.env.VITE_SUPABASE_PUBLISHABLE_DEFAULT_KEY;
 
 async function gotrue(
   path: string,
diff --git a/frontend/editor/src/saas/setupTests.ts b/frontend/editor/src/saas/setupTests.ts
index 3e8864e49e..6b04e18efd 100644
--- a/frontend/editor/src/saas/setupTests.ts
+++ b/frontend/editor/src/saas/setupTests.ts
@@ -130,7 +130,7 @@ Object.defineProperty(globalThis, "crypto", {
         }
         return array;
       }),
-  } as unknown as Crypto,
+  },
   writable: true,
   configurable: true,
 });