Add layered error boundaries to compliance portal

Introduce global, page, and section-level error handling for the
compliance portal so a failure is contained at the smallest possible
scope instead of blanking the whole page.

Add a portal-local Relay fetch that throws only request-level errors
(and always redirects on UNAUTHENTICATED) while leaving field-level
errors in the response, so Relay surfaces them at the reading component
through @throwOnFieldError and the nearest boundary. Add a NotFoundError
for node __typename mismatches mapped to a not-found page.

Ship reusable v2 kit primitives (ErrorBoundary, ErrorState, InlineError)
matching the Figma global/local/inline designs, wire the bootstrap and
route boundaries, and demonstrate section and row boundaries on the home
page. Update the error-handling and relay guides accordingly.

Signed-off-by: Émile Ré <emile@probo.com>

apps/compliance-portal/src/App.tsx

@@ -18,15 +18,19 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
+import { ErrorBoundary } from "@probo/ui/src/v2/ErrorBoundary/ErrorBoundary";
 import { RouterProvider } from "react-router";
 
+import { BootstrapError } from "#/components/errors/BootstrapError";
 import { RelayProvider } from "#/lib/relay/RelayProvider";
 import { router } from "#/routes";
 
 export function App() {
   return (
-    <RelayProvider>
+    <ErrorBoundary fallback={<BootstrapError />}>
-      <RouterProvider router={router} />
+      <RelayProvider>
-    </RelayProvider>
+        <RouterProvider router={router} />
+      </RelayProvider>
+    </ErrorBoundary>
   );
 }

apps/compliance-portal/src/_locales/en-US.json

@@ -36,6 +36,32 @@
     "description": "The page you are looking for does not exist or has moved.",
     "backHome": "Back to home"
   },
+  "errors": {
+    "notFound": {
+      "title": "Page not found",
+      "description": "The page you're looking for doesn't exist or may have been moved."
+    },
+    "forbidden": {
+      "title": "Access denied",
+      "description": "You don't have permission to view this page."
+    },
+    "serverError": {
+      "title": "Something went wrong",
+      "description": "We hit an unexpected error. Please try again in a moment."
+    },
+    "generic": {
+      "title": "Something went wrong",
+      "description": "We hit an unexpected error. Please try again in a moment."
+    },
+    "actions": {
+      "backToTrustCenter": "Back to trust center",
+      "tryAgain": "Try again"
+    },
+    "inline": {
+      "message": "Unable to load content",
+      "retry": "Retry"
+    }
+  },
   "footer": {
     "poweredBy": "Powered by"
   },

apps/compliance-portal/src/_locales/fr-FR.json

@@ -36,6 +36,32 @@
     "description": "La page que vous recherchez n'existe pas ou a été déplacée.",
     "backHome": "Retour à l'accueil"
   },
+  "errors": {
+    "notFound": {
+      "title": "Page introuvable",
+      "description": "La page que vous recherchez n'existe pas ou a été déplacée."
+    },
+    "forbidden": {
+      "title": "Accès refusé",
+      "description": "Vous n'avez pas l'autorisation de consulter cette page."
+    },
+    "serverError": {
+      "title": "Une erreur est survenue",
+      "description": "Une erreur inattendue s'est produite. Veuillez réessayer dans un instant."
+    },
+    "generic": {
+      "title": "Une erreur est survenue",
+      "description": "Une erreur inattendue s'est produite. Veuillez réessayer dans un instant."
+    },
+    "actions": {
+      "backToTrustCenter": "Retour au trust center",
+      "tryAgain": "Réessayer"
+    },
+    "inline": {
+      "message": "Impossible de charger le contenu",
+      "retry": "Réessayer"
+    }
+  },
   "footer": {
     "poweredBy": "Propulsé par"
   },

apps/compliance-portal/src/components/ComplianceFrameworks/ComplianceFrameworksSection.tsx

@@ -18,6 +18,8 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
+import { ErrorBoundary } from "@probo/ui/src/v2/ErrorBoundary/ErrorBoundary";
+import { InlineError } from "@probo/ui/src/v2/InlineError/InlineError";
 import { useTranslation } from "react-i18next";
 import { graphql, useFragment } from "react-relay";
 
@@ -26,8 +28,11 @@ import { HomeSection } from "#/components/HomeSection/HomeSection";
 import type { ComplianceFrameworksSection_trustCenter$key } from "./__generated__/ComplianceFrameworksSection_trustCenter.graphql";
 import { ComplianceFrameworkListItem } from "./ComplianceFrameworkListItem";
 
+// @throwOnFieldError makes a field error in this fragment throw at the read
+// below, where the section's ErrorBoundary contains it. See
+// contrib/claude/error-handling.md.
 const complianceFrameworksSectionFragment = graphql`
-  fragment ComplianceFrameworksSection_trustCenter on TrustCenter {
+  fragment ComplianceFrameworksSection_trustCenter on TrustCenter @throwOnFieldError {
     complianceFrameworks(first: 8) {
       edges {
         node {
@@ -44,9 +49,30 @@ interface ComplianceFrameworksSectionProps {
 }
 
 // "Compliance" section: the grid of certification frameworks the trust center
-// covers.
+// covers. Wraps its data-reading content in a boundary so a load failure
+// degrades to an inline error instead of taking down the page.
 export function ComplianceFrameworksSection({ trustCenterKey }: ComplianceFrameworksSectionProps) {
   const { t } = useTranslation();
+
+  return (
+    <ErrorBoundary
+      fallback={(_, reset) => (
+        <HomeSection title={t("home.sections.compliance")}>
+          <InlineError
+            message={t("errors.inline.message")}
+            retryLabel={t("errors.inline.retry")}
+            onRetry={reset}
+          />
+        </HomeSection>
+      )}
+    >
+      <ComplianceFrameworksSectionContent trustCenterKey={trustCenterKey} />
+    </ErrorBoundary>
+  );
+}
+
+function ComplianceFrameworksSectionContent({ trustCenterKey }: ComplianceFrameworksSectionProps) {
+  const { t } = useTranslation();
   const data = useFragment(complianceFrameworksSectionFragment, trustCenterKey);
   const frameworks = data.complianceFrameworks.edges.map(edge => edge.node);
 

apps/compliance-portal/src/components/MailingListUpdateListItem/MailingListUpdateListItem.tsx

@@ -29,7 +29,7 @@ import { formatRelativeTime } from "#/lib/datetime/relativeTime";
 import type { MailingListUpdateListItem_update$key } from "./__generated__/MailingListUpdateListItem_update.graphql";
 
 const mailingListUpdateListItemFragment = graphql`
-  fragment MailingListUpdateListItem_update on MailingListUpdate {
+  fragment MailingListUpdateListItem_update on MailingListUpdate @throwOnFieldError {
     id
     title
     updatedAt

apps/compliance-portal/src/components/RecentUpdates/RecentUpdatesSection.tsx

@@ -19,6 +19,8 @@
 // SOFTWARE.
 
 import { Link } from "@probo/ui/src/v2/Button/Link";
+import { ErrorBoundary } from "@probo/ui/src/v2/ErrorBoundary/ErrorBoundary";
+import { InlineError } from "@probo/ui/src/v2/InlineError/InlineError";
 import { useTranslation } from "react-i18next";
 import { graphql, useFragment } from "react-relay";
 
@@ -28,8 +30,10 @@ import { dotPatternStyle } from "#/components/MediaTile/variants";
 
 import type { RecentUpdatesSection_trustCenter$key } from "./__generated__/RecentUpdatesSection_trustCenter.graphql";
 
+// @throwOnFieldError surfaces a field error at the read below so the section
+// ErrorBoundary contains it. See contrib/claude/error-handling.md.
 const recentUpdatesSectionFragment = graphql`
-  fragment RecentUpdatesSection_trustCenter on TrustCenter {
+  fragment RecentUpdatesSection_trustCenter on TrustCenter @throwOnFieldError {
     updates(first: 5) {
       edges {
         node {
@@ -46,9 +50,29 @@ interface RecentUpdatesSectionProps {
 }
 
 // "Recent updates" section: the latest mailing-list updates as a list, with a
-// link to the full updates page.
+// link to the full updates page. A load failure degrades to an inline error.
 export function RecentUpdatesSection({ trustCenterKey }: RecentUpdatesSectionProps) {
   const { t } = useTranslation();
+
+  return (
+    <ErrorBoundary
+      fallback={(_, reset) => (
+        <HomeSection title={t("home.sections.recentUpdates")}>
+          <InlineError
+            message={t("errors.inline.message")}
+            retryLabel={t("errors.inline.retry")}
+            onRetry={reset}
+          />
+        </HomeSection>
+      )}
+    >
+      <RecentUpdatesSectionContent trustCenterKey={trustCenterKey} />
+    </ErrorBoundary>
+  );
+}
+
+function RecentUpdatesSectionContent({ trustCenterKey }: RecentUpdatesSectionProps) {
+  const { t } = useTranslation();
   const data = useFragment(recentUpdatesSectionFragment, trustCenterKey);
   const updates = data.updates.edges.map(edge => edge.node);
 
@@ -70,7 +94,22 @@ export function RecentUpdatesSection({ trustCenterKey }: RecentUpdatesSectionPro
         <div aria-hidden className="pointer-events-none absolute inset-0 bg-linear-to-r from-sand-1/0 to-sand-1 to-[96px]" />
         <div className="relative divide-y divide-sand-a2">
           {updates.map(update => (
-            <MailingListUpdateListItem key={update.id} updateKey={update} />
+            // A single failing row degrades to a compact horizontal inline error.
+            <ErrorBoundary
+              key={update.id}
+              fallback={(_, reset) => (
+                <div className="px-6 py-4">
+                  <InlineError
+                    layout="horizontal"
+                    message={t("errors.inline.message")}
+                    retryLabel={t("errors.inline.retry")}
+                    onRetry={reset}
+                  />
+                </div>
+              )}
+            >
+              <MailingListUpdateListItem updateKey={update} />
+            </ErrorBoundary>
           ))}
         </div>
       </div>

apps/compliance-portal/src/components/errors/BootstrapError.tsx

@@ -0,0 +1,45 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+import { Anchor } from "@probo/ui/src/v2/Button/Anchor";
+import { Button } from "@probo/ui/src/v2/Button/Button";
+import { ErrorState } from "@probo/ui/src/v2/ErrorState/ErrorState";
+import { useTranslation } from "react-i18next";
+
+import { getPathPrefix } from "#/lib/http/pathPrefix";
+
+// Outermost fallback for failures that happen before (or in) the router itself.
+// It cannot use the router (no context yet), so navigation is a plain anchor and
+// recovery is a hard reload.
+export function BootstrapError() {
+  const { t } = useTranslation();
+
+  return (
+    <ErrorState
+      fullPage
+      title={t("errors.generic.title")}
+      description={t("errors.generic.description")}
+      actions={(
+        <>
+          <Anchor href={getPathPrefix() || "/"} variant="solid" color="neutral" highContrast size={2}>
+            {t("errors.actions.backToTrustCenter")}
+          </Anchor>
+          <Button variant="soft" color="neutral" size={2} onClick={() => window.location.reload()}>
+            {t("errors.actions.tryAgain")}
+          </Button>
+        </>
+      )}
+    />
+  );
+}

apps/compliance-portal/src/components/errors/GlobalError.tsx

@@ -0,0 +1,89 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+import { ForbiddenError, InternalServerError, UnAuthenticatedError } from "@probo/relay";
+import { Button } from "@probo/ui/src/v2/Button/Button";
+import { Link } from "@probo/ui/src/v2/Button/Link";
+import { ErrorState } from "@probo/ui/src/v2/ErrorState/ErrorState";
+import { useTranslation } from "react-i18next";
+
+import { NotFoundError } from "#/lib/relay/errors";
+
+interface ErrorContent {
+  code?: string;
+  titleKey: string;
+  descriptionKey: string;
+}
+
+// Map a caught error to the page-level copy. Recognizes the portal error
+// classes first, then falls back to the code embedded in generic Error messages
+// (thrown request-level by lib/relay/fetch.ts).
+function resolveContent(error: unknown): ErrorContent {
+  const message = error instanceof Error ? error.message : "";
+
+  if (error instanceof NotFoundError || message.includes("NOT_FOUND")) {
+    return { code: "404", titleKey: "errors.notFound.title", descriptionKey: "errors.notFound.description" };
+  }
+
+  if (
+    error instanceof ForbiddenError
+    || error instanceof UnAuthenticatedError
+    || message.includes("FORBIDDEN")
+    || message.includes("UNAUTHENTICATED")
+  ) {
+    return { code: "403", titleKey: "errors.forbidden.title", descriptionKey: "errors.forbidden.description" };
+  }
+
+  if (error instanceof InternalServerError || message.includes("INTERNAL_SERVER_ERROR")) {
+    return { code: "500", titleKey: "errors.serverError.title", descriptionKey: "errors.serverError.description" };
+  }
+
+  return { titleKey: "errors.generic.title", descriptionKey: "errors.generic.description" };
+}
+
+interface GlobalErrorProps {
+  error: unknown;
+  // When provided, a "Try again" secondary action is shown.
+  onRetry?: () => void;
+  // Full viewport (standalone) vs inside the app chrome (in-shell).
+  fullPage?: boolean;
+}
+
+// Page-level error fallback: renders the v2 ErrorState with portal copy and
+// actions. Used by the bootstrap boundary and the route boundaries.
+export function GlobalError({ error, onRetry, fullPage = false }: GlobalErrorProps) {
+  const { t } = useTranslation();
+  const { code, titleKey, descriptionKey } = resolveContent(error);
+
+  return (
+    <ErrorState
+      fullPage={fullPage}
+      code={code}
+      title={t(titleKey)}
+      description={t(descriptionKey)}
+      actions={(
+        <>
+          <Link to="/" variant="solid" color="neutral" highContrast size={2}>
+            {t("errors.actions.backToTrustCenter")}
+          </Link>
+          {onRetry && (
+            <Button variant="soft" color="neutral" size={2} onClick={onRetry}>
+              {t("errors.actions.tryAgain")}
+            </Button>
+          )}
+        </>
+      )}
+    />
+  );
+}

apps/compliance-portal/src/components/errors/PageErrorBoundary.tsx

@@ -0,0 +1,30 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+import { useRouteError } from "react-router";
+
+import { GlobalError } from "./GlobalError";
+
+// Child-route boundary: a page failure is contained to the layout's Outlet, so
+// the error renders inside the app chrome (TopBar + footer survive).
+export function PageErrorBoundary() {
+  const error = useRouteError();
+
+  return (
+    <GlobalError
+      error={error}
+      onRetry={() => window.location.reload()}
+    />
+  );
+}

apps/compliance-portal/src/components/errors/RootErrorBoundary.tsx

@@ -0,0 +1,32 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+import { useRouteError } from "react-router";
+
+import { GlobalError } from "./GlobalError";
+
+// Root route boundary: a failure in the layout (or anything above the page
+// boundaries) takes down the whole tree, so it renders a standalone full-page
+// error without the app chrome.
+export function RootErrorBoundary() {
+  const error = useRouteError();
+
+  return (
+    <GlobalError
+      error={error}
+      fullPage
+      onRetry={() => window.location.reload()}
+    />
+  );
+}

apps/compliance-portal/src/lib/relay/environment.ts

@@ -18,10 +18,10 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-import { makeFetchQuery } from "@probo/relay";
 import { Environment, Network, RecordSource, Store } from "relay-runtime";
 
 import { buildEndpoint } from "#/lib/http/endpoint";
+import { makeFetchQuery } from "#/lib/relay/fetch";
 
 const store = new Store(new RecordSource(), {
   queryCacheExpirationTime: 1 * 60 * 1000,

apps/compliance-portal/src/lib/relay/errors.ts

@@ -0,0 +1,25 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+// Thrown when a fetched `node(id:)` resolves to a type other than the one the
+// view expects (e.g. `node.__typename !== "MailingListUpdate"`). Treated as a
+// not-found (404) by the error boundaries. Prefer this over a bare
+// `throw new Error(...)` so the boundary can render the dedicated 404 state.
+export class NotFoundError extends Error {
+  constructor(message?: string) {
+    super(message ?? "NOT_FOUND");
+    this.name = "NotFoundError";
+    Object.setPrototypeOf(this, NotFoundError.prototype);
+  }
+}

apps/compliance-portal/src/lib/relay/fetch.ts

@@ -0,0 +1,123 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+import { ForbiddenError, InternalServerError, UnAuthenticatedError } from "@probo/relay";
+import { type GraphQLError } from "graphql";
+import { type FetchFunction, type GraphQLResponse } from "relay-runtime";
+
+// A GraphQL error is "request-level" when it has no `path` — it applies to the
+// whole operation (auth, malformed request, transport) rather than a single
+// field. Field-level errors carry a `path` and are left in the response so
+// Relay can attribute them to the reading field; combined with
+// `@throwOnFieldError` on a query/fragment, they surface at the nearest error
+// boundary around the component that reads them, instead of collapsing the whole
+// operation. See contrib/claude/error-handling.md.
+const isRequestLevel = (error: GraphQLError) =>
+  error.path === undefined || error.path === null || error.path.length === 0;
+
+// The portal fetch only throws for request-level failures. Everything else
+// (field-level errors) flows through to Relay untouched.
+export const makeFetchQuery = (endpoint: string): FetchFunction => {
+  return async (request, variables, _, uploadables) => {
+    const requestInit: RequestInit = {
+      method: "POST",
+      credentials: "include",
+      headers: {},
+    };
+
+    if (uploadables) {
+      const formData = new FormData();
+      formData.append(
+        "operations",
+        JSON.stringify({
+          operationName: request.name,
+          query: request.text,
+          variables: variables,
+        }),
+      );
+
+      const uploadableMap: {
+        [key: string]: string[];
+      } = {};
+      const uploadableKeys = Object.keys(uploadables);
+
+      uploadableKeys.forEach((key) => {
+        uploadableMap[key] = [`variables.${key}`];
+      });
+
+      formData.append("map", JSON.stringify(uploadableMap));
+
+      uploadableKeys.forEach((key) => {
+        formData.append(key, uploadables[key]);
+      });
+
+      requestInit.body = formData;
+    } else {
+      requestInit.headers = {
+        "Accept": "application/graphql-response+json; charset=utf-8, application/json; charset=utf-8",
+        "Content-Type": "application/json",
+      };
+
+      requestInit.body = JSON.stringify({
+        operationName: request.name,
+        query: request.text,
+        variables,
+      });
+    }
+
+    const response = await fetch(endpoint, requestInit);
+
+    if (response.status === 500) {
+      throw new InternalServerError();
+    }
+
+    const json = (await response.json()) as GraphQLResponse & {
+      errors?: GraphQLError[];
+    };
+
+    if (json.errors) {
+      // An unauthenticated session is always a global concern: the backend
+      // attaches the resolver path even to auth errors, so we must scan every
+      // error (not just request-level ones) and redirect regardless of where it
+      // surfaced.
+      const unauthenticated = json.errors.find(
+        error => error.extensions?.code === "UNAUTHENTICATED",
+      );
+      if (unauthenticated) {
+        throw new UnAuthenticatedError(unauthenticated.message);
+      }
+
+      // Everything else is only thrown here when it is request-level (no path) —
+      // a whole-operation failure. Field-level errors (including a FORBIDDEN on
+      // a single field/section) are left in the response so Relay surfaces them
+      // at the reading component via @throwOnFieldError, containing the failure
+      // to that component's boundary instead of the whole page.
+      const requestErrors = json.errors.filter(isRequestLevel);
+
+      const forbidden = requestErrors.find(
+        error => error.extensions?.code === "FORBIDDEN",
+      );
+      if (forbidden) {
+        throw new ForbiddenError(forbidden.message);
+      }
+
+      const requestError = requestErrors[0];
+      if (requestError) {
+        throw new Error(requestError.message);
+      }
+    }
+
+    return json;
+  };
+};

apps/compliance-portal/src/pages/HomePage.tsx

@@ -32,7 +32,7 @@ import { TrustedBySection } from "#/components/TrustedBy/TrustedBySection";
 import type { HomePageQuery } from "./__generated__/HomePageQuery.graphql";
 
 export const homePageQuery = graphql`
-  query HomePageQuery {
+  query HomePageQuery @throwOnFieldError {
     currentTrustCenter @required(action: THROW) {
       organization {
         name

apps/compliance-portal/src/pages/updates/UpdateDetailPage.tsx

@@ -28,13 +28,14 @@ import { graphql, usePreloadedQuery } from "react-relay";
 
 import { HeaderBand } from "#/components/HeaderBand/HeaderBand";
 import { formatDate } from "#/lib/datetime/formatDate";
+import { NotFoundError } from "#/lib/relay/errors";
 
 import type { UpdateDetailPageQuery } from "./__generated__/UpdateDetailPageQuery.graphql";
 import { UpdatesSubscribeButton } from "./_components/UpdatesSubscribeButton";
 import { updateArticle } from "./_components/variants";
 
 export const updateDetailPageQuery = graphql`
-  query UpdateDetailPageQuery($updateId: ID!) {
+  query UpdateDetailPageQuery($updateId: ID!) @throwOnFieldError {
     node(id: $updateId) {
       __typename
       ... on MailingListUpdate {
@@ -55,7 +56,7 @@ export function UpdateDetailPage({ queryRef }: UpdateDetailPageProps) {
   const data = usePreloadedQuery<UpdateDetailPageQuery>(updateDetailPageQuery, queryRef);
 
   if (data.node?.__typename !== "MailingListUpdate") {
-    throw new Error("Update not found");
+    throw new NotFoundError("Update not found");
   }
   const update = data.node;
 

apps/compliance-portal/src/routes.tsx

@@ -22,6 +22,8 @@ import { lazy } from "@probo/react-lazy";
 import { type AppRoute, routeFromAppRoute } from "@probo/routes";
 import { createBrowserRouter } from "react-router";
 
+import { PageErrorBoundary } from "#/components/errors/PageErrorBoundary";
+import { RootErrorBoundary } from "#/components/errors/RootErrorBoundary";
 import { getPathPrefix } from "#/lib/http/pathPrefix";
 import { HomePageSkeleton } from "#/pages/HomePageSkeleton";
 import { MainLayoutSkeleton } from "#/pages/MainLayoutSkeleton";
@@ -33,25 +35,34 @@ const routes = [
     path: "/",
     Fallback: MainLayoutSkeleton,
     Component: lazy(() => import("#/pages/MainLayoutLoader")),
+    // A layout failure takes down the shell, so it shows a standalone full page.
+    ErrorBoundary: RootErrorBoundary,
     children: [
       {
-        index: true,
+        // Pathless layout route: page failures bubble here and render inside the
-        Fallback: HomePageSkeleton,
+        // MainLayout Outlet, keeping the TopBar and footer chrome.
-        Component: lazy(() => import("#/pages/HomePageLoader")),
+        ErrorBoundary: PageErrorBoundary,
-      },
+        children: [
-      {
+          {
-        path: "documents",
+            index: true,
-        Component: lazy(() => import("#/pages/DocumentsPage")),
+            Fallback: HomePageSkeleton,
-      },
+            Component: lazy(() => import("#/pages/HomePageLoader")),
-      ...subprocessorRoutes,
+          },
-      ...updateRoutes,
+          {
-      {
+            path: "documents",
-        path: "requests",
+            Component: lazy(() => import("#/pages/DocumentsPage")),
-        Component: lazy(() => import("#/pages/RequestsPage")),
+          },
-      },
+          ...subprocessorRoutes,
-      {
+          ...updateRoutes,
-        path: "*",
+          {
-        Component: lazy(() => import("#/pages/NotFoundPage")),
+            path: "requests",
+            Component: lazy(() => import("#/pages/RequestsPage")),
+          },
+          {
+            path: "*",
+            Component: lazy(() => import("#/pages/NotFoundPage")),
+          },
+        ],
       },
     ],
   },

contrib/claude/error-handling.md

@@ -156,6 +156,93 @@ function PublishButton() {
 
 For Relay mutations, prefer the built-in `onCompleted` / `onError` callbacks (see [`relay.md`](relay.md)) over a manual `try`/`catch`; use `try`/`catch` for non-Relay async work (fetch, parsing, third-party SDKs).
 
+## Relay field errors and fragment-level boundaries
+
+A GraphQL response can be **partial**: `data` is present but one field carries an
+error (with a `path`). To contain such a failure to the component that reads the
+bad field — instead of collapsing the whole page — two pieces cooperate:
+
+1. **The fetch layer only throws request-level errors.** A request-level error
+   has **no `path`** (auth, malformed request, transport) and applies to the
+   whole operation, so it throws and propagates to the nearest boundary.
+   Field-level errors (those with a `path`) are **left in the response** so Relay
+   can attribute them to the reading field.
+
+   The compliance-portal wires this in its own
+   [`apps/compliance-portal/src/lib/relay/fetch.ts`](../../apps/compliance-portal/src/lib/relay/fetch.ts)
+   (it does **not** use `@probo/relay`'s `makeFetchQuery`, which throws for the
+   whole operation on any known code).
+
+2. **`@throwOnFieldError` on the query/fragment that reads the field.** With the
+   directive set, a field error throws **at the read site** (`usePreloadedQuery`
+   for a query, `useFragment` for a fragment). Put it on the **fragment** to
+   isolate a section/row, and on the **query** to route page-level field errors
+   to the route boundary.
+
+Because `useFragment` throws in the component body (not in a child), the boundary
+must be an **ancestor**. Split the component into a thin wrapper (holds the
+`ErrorBoundary`) and a `*Content` child (reads the fragment):
+
+```tsx
+export function RecentUpdatesSection({ trustCenterKey }: Props) {
+  const { t } = useTranslation();
+  return (
+    <ErrorBoundary
+      fallback={(_, reset) => (
+        <InlineError message={t("errors.inline.message")} onRetry={reset} retryLabel={t("errors.inline.retry")} />
+      )}
+    >
+      <RecentUpdatesSectionContent trustCenterKey={trustCenterKey} />
+    </ErrorBoundary>
+  );
+}
+
+function RecentUpdatesSectionContent({ trustCenterKey }: Props) {
+  const data = useFragment(fragment, trustCenterKey); // throws here on a field error
+  // ...
+}
+
+const fragment = graphql`
+  fragment RecentUpdatesSection_trustCenter on TrustCenter @throwOnFieldError { ... }
+`;
+```
+
+The portal ships three fallback tiers, all backed by the same `ErrorBoundary`:
+
+| Tier | Placement | Fallback |
+|------|-----------|----------|
+| Global (bootstrap) | around `RouterProvider` in `App.tsx`, and the root route | `ErrorState` full page (standalone) |
+| Page | pathless child route inside the layout | `ErrorState` inside the shell (TopBar/footer survive) |
+| Section / row | around a fragment-reading subtree | `InlineError` (vertical for sections, horizontal for rows) with a retry |
+
+`ErrorState` and `InlineError` are presentational v2 kit components (see
+[`ui.md`](ui.md)); the app maps the caught error to copy/actions and passes them
+in.
+
+## Custom errors for node-type mismatches
+
+When a page fetches `node(id:)` and the resolved `__typename` is not the type the
+view expects, throw a dedicated error, not a bare `Error`, so the boundary can
+render the correct state (404):
+
+```tsx
+// Good — a typed error the boundary maps to the not-found page
+import { NotFoundError } from "#/lib/relay/errors";
+
+if (data.node?.__typename !== "MailingListUpdate") {
+  throw new NotFoundError("Update not found");
+}
+```
+
+```tsx
+// Bad — an untyped error the boundary can only show as a generic failure
+if (data.node?.__typename !== "MailingListUpdate") {
+  throw new Error("Update not found");
+}
+```
+
+See [`relay.md`](relay.md) (Node type guards).
+
 ## Placement guidance
 
 - **Route root** — one boundary so an unhandled failure shows a full-page error instead of a blank screen.

contrib/claude/relay.md

@@ -261,6 +261,52 @@ const logoUrl = organization.logo?.downloadUrl ?? undefined; // logo stays optio
 
 Do **not** reach for `@required` to silence nullability on fields that are *genuinely* optional (an avatar, a logo, a description that may be empty). Those keep their nullable type and get a real empty/fallback state. Likewise, never select a field, mark it `@required(action: THROW)`, and rely on the throw as control flow for an expected-empty case — that is an error path, not a branch. And there is no need to annotate fields the schema already declares non-null (`String!`, `Organization!`).
 
+### Node type guards
+
+A `node(id:)` query resolves to an interface (`Node`), so the page must narrow it
+to the concrete type before use. When the `__typename` is not what the view
+expects, throw a **typed** error the nearest error boundary can map to the right
+state (a not-found page), not a bare `Error`:
+
+```tsx
+// Good — NotFoundError is mapped to the 404 state by the boundary
+import { NotFoundError } from "#/lib/relay/errors";
+
+const data = usePreloadedQuery<UpdateDetailPageQuery>(updateDetailPageQuery, queryRef);
+if (data.node?.__typename !== "MailingListUpdate") {
+  throw new NotFoundError("Update not found");
+}
+const update = data.node; // narrowed to MailingListUpdate
+```
+
+```tsx
+// Bad — an untyped error only renders a generic failure
+if (data.node?.__typename !== "MailingListUpdate") {
+  throw new Error("Update not found");
+}
+```
+
+This is a client-side invariant, distinct from server field errors (which flow
+through `@throwOnFieldError`; see below). See
+[`error-handling.md`](error-handling.md).
+
+### Field errors (`@throwOnFieldError`)
+
+To contain a **partial** GraphQL failure (data present, one field errored) to the
+component that reads the bad field, annotate the query or fragment with
+`@throwOnFieldError`. The field error then throws at the read site
+(`usePreloadedQuery` / `useFragment`) and is caught by the nearest `ErrorBoundary`
+— on a **fragment** to isolate a section/row, on a **query** for page-level
+fields. This only works when the network layer leaves field-level errors in the
+response (see the portal fetch in [`error-handling.md`](error-handling.md)).
+
+```graphql
+# Good — a field error in this fragment throws at the section's useFragment
+fragment RecentUpdatesSection_trustCenter on TrustCenter @throwOnFieldError {
+  updates(first: 5) { edges { node { id ...MailingListUpdateListItem_update } } }
+}
+```
+
 ### Refetchable fragments
 
 For lists that support sorting and pagination, use `@refetchable` with `@argumentDefinitions`:

packages/ui/src/v2/ErrorBoundary/ErrorBoundary.tsx

@@ -0,0 +1,55 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+import { Component, type ErrorInfo, type ReactNode } from "react";
+
+export interface ErrorBoundaryProps {
+  children: ReactNode;
+  // A node, or a render function that receives the caught error + a reset fn.
+  fallback?: ReactNode | ((error: Error, reset: () => void) => ReactNode);
+  onError?: (error: Error, info: ErrorInfo) => void;
+}
+
+interface ErrorBoundaryState {
+  error: Error | null;
+}
+
+// The single reusable error boundary primitive (the sanctioned use of a class).
+// Generic — works at bootstrap, route, section, or component level; only the
+// placement and the `fallback` differ. See contrib/claude/error-handling.md.
+export class ErrorBoundary extends Component<ErrorBoundaryProps, ErrorBoundaryState> {
+  state: ErrorBoundaryState = { error: null };
+
+  static getDerivedStateFromError(error: Error): ErrorBoundaryState {
+    return { error };
+  }
+
+  componentDidCatch(error: Error, info: ErrorInfo) {
+    this.props.onError?.(error, info);
+  }
+
+  reset = () => this.setState({ error: null });
+
+  render() {
+    const { error } = this.state;
+    if (error) {
+      const { fallback } = this.props;
+      if (typeof fallback === "function") {
+        return fallback(error, this.reset);
+      }
+      return fallback ?? null;
+    }
+    return this.props.children;
+  }
+}

packages/ui/src/v2/ErrorState/ErrorState.stories.tsx

@@ -0,0 +1,73 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+import type { Meta, StoryObj } from "@storybook/react";
+
+import { Button } from "../Button/Button";
+
+import { ErrorState } from "./ErrorState";
+
+const actions = (
+  <>
+    <Button size={2} color="neutral" highContrast>Back to trust center</Button>
+    <Button size={2} variant="soft" color="neutral">Contact support</Button>
+  </>
+);
+
+export default {
+  title: "v2/ErrorState",
+  component: ErrorState,
+  args: {
+    code: "404",
+    title: "Page not found",
+    description: "The page you're looking for doesn't exist or may have been moved.",
+    actions,
+  },
+} satisfies Meta<typeof ErrorState>;
+
+type Story = StoryObj<typeof ErrorState>;
+
+export const Playground: Story = {};
+
+export const NotFound: Story = {
+  args: {
+    code: "404",
+    title: "Page not found",
+    description: "The page you're looking for doesn't exist or may have been moved.",
+  },
+};
+
+export const Forbidden: Story = {
+  args: {
+    code: "403",
+    title: "Access denied",
+    description: "You don't have permission to view this page.",
+  },
+};
+
+export const ServerError: Story = {
+  args: {
+    code: "500",
+    title: "Something went wrong",
+    description: "We hit an unexpected error. Please try again later.",
+  },
+};
+
+export const WithoutCode: Story = {
+  args: {
+    code: undefined,
+    title: "Something went wrong",
+    description: "We hit an unexpected error. Please try again later.",
+  },
+};

packages/ui/src/v2/ErrorState/ErrorState.tsx

@@ -0,0 +1,59 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+import type { ReactNode } from "react";
+import type { VariantProps } from "tailwind-variants/lite";
+
+import { Heading } from "../typography/Heading";
+import { Text } from "../typography/Text";
+
+import { errorState } from "./variants";
+
+export type ErrorStateProps
+  = VariantProps<typeof errorState>
+    & {
+      title: string;
+      // Optional status code / label shown above the title (e.g. "404").
+      code?: string;
+      description?: string;
+      // Action slot (primary / secondary buttons). Left to the caller so the
+      // native Button/Link props stay editable. See contrib/claude/ui.md.
+      actions?: ReactNode;
+      className?: string;
+    };
+
+// Presentational full-page error message (Figma "Error message / Page"). Copy
+// and actions come from the caller; this only lays them out.
+export function ErrorState({ code, title, description, actions, fullPage, className }: ErrorStateProps) {
+  const slots = errorState({ fullPage });
+
+  return (
+    <div className={slots.root({ className })}>
+      <div className={slots.block()}>
+        <div className={slots.content()}>
+          {code && (
+            <Text size={1} color="gold" align="center">{code}</Text>
+          )}
+          <Heading level={1} size={4} weight="medium" align="center" highContrast>
+            {title}
+          </Heading>
+          {description && (
+            <Text size={2} color="neutral" align="center">{description}</Text>
+          )}
+        </div>
+        {actions && <div className={slots.actions()}>{actions}</div>}
+      </div>
+    </div>
+  );
+}

packages/ui/src/v2/ErrorState/variants.ts

@@ -0,0 +1,40 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+import { tv } from "tailwind-variants/lite";
+
+// Centered full-page error message block for portal boundaries (Figma
+// "Error message / Page"). Used for 404 / 403 / 500 / generic page-level errors.
+//   root     the centering wrapper (page vs in-shell sizing)
+//   block    the 256px content column (code + title + description + actions)
+//   content  the stacked text region
+//   actions  the primary/secondary action row
+export const errorState = tv({
+  slots: {
+    root: "flex w-full items-center justify-center",
+    block: "flex min-w-64 max-w-md flex-col items-center gap-6 text-center",
+    content: "flex w-full flex-col items-center gap-2",
+    actions: "flex items-center justify-center gap-2",
+  },
+  variants: {
+    // Standalone fills the viewport; in-shell sits inside the app chrome.
+    fullPage: {
+      true: { root: "min-h-screen px-6 py-16" },
+      false: { root: "px-6 py-12" },
+    },
+  },
+  defaultVariants: {
+    fullPage: false,
+  },
+});

packages/ui/src/v2/InlineError/InlineError.stories.tsx

@@ -0,0 +1,63 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+import type { Meta, StoryObj } from "@storybook/react";
+
+import { InlineError } from "./InlineError";
+
+const message = "Unable to load content";
+
+export default {
+  title: "v2/InlineError",
+  component: InlineError,
+  args: {
+    layout: "vertical",
+    message,
+    onRetry: () => {},
+  },
+} satisfies Meta<typeof InlineError>;
+
+type Story = StoryObj<typeof InlineError>;
+
+export const Playground: Story = {
+  render: args => (
+    <div className="w-96">
+      <InlineError {...args} />
+    </div>
+  ),
+};
+
+export const Vertical: Story = {
+  render: () => (
+    <div className="w-96">
+      <InlineError layout="vertical" message={message} onRetry={() => {}} />
+    </div>
+  ),
+};
+
+export const Horizontal: Story = {
+  render: () => (
+    <div className="w-96">
+      <InlineError layout="horizontal" message={message} onRetry={() => {}} />
+    </div>
+  ),
+};
+
+export const WithoutRetry: Story = {
+  render: () => (
+    <div className="w-96">
+      <InlineError layout="vertical" message={message} />
+    </div>
+  ),
+};

packages/ui/src/v2/InlineError/InlineError.tsx

@@ -0,0 +1,47 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+import type { VariantProps } from "tailwind-variants/lite";
+
+import { Button } from "../Button/Button";
+import { Text } from "../typography/Text";
+
+import { inlineError } from "./variants";
+
+export type InlineErrorProps
+  = VariantProps<typeof inlineError>
+    & {
+      message: string;
+      // Retry handler. When omitted, the retry action is hidden.
+      onRetry?: () => void;
+      retryLabel?: string;
+      className?: string;
+    };
+
+// Presentational inline error (Figma "Error message / Inline"). Copy and the
+// retry handler come from the caller; this only lays them out.
+export function InlineError({ layout, message, onRetry, retryLabel = "Retry", className }: InlineErrorProps) {
+  const slots = inlineError({ layout });
+
+  return (
+    <div className={slots.root({ className })}>
+      <Text size={2} color="neutral" className={slots.message()}>{message}</Text>
+      {onRetry && (
+        <Button size={2} variant="soft" color="neutral" onClick={onRetry}>
+          {retryLabel}
+        </Button>
+      )}
+    </div>
+  );
+}

packages/ui/src/v2/InlineError/variants.ts

@@ -0,0 +1,41 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+import { tv } from "tailwind-variants/lite";
+
+// Localized inline error for section / card / list / row load failures (Figma
+// "Error message / Inline").
+//   vertical    centered column for contained spaces (sections, cards, panels)
+//   horizontal  compact row for list / table rows
+export const inlineError = tv({
+  slots: {
+    root: "flex w-full gap-2",
+    message: "",
+  },
+  variants: {
+    layout: {
+      vertical: {
+        root: "flex-col items-center justify-center text-center",
+        message: "w-full",
+      },
+      horizontal: {
+        root: "flex-row items-center",
+        message: "flex-1 text-left",
+      },
+    },
+  },
+  defaultVariants: {
+    layout: "vertical",
+  },
+});