diff --git a/packages/react/src/api/oauth-popup.ts b/packages/react/src/api/oauth-popup.ts
index b7e7dca66..a50fcb68a 100644
--- a/packages/react/src/api/oauth-popup.ts
+++ b/packages/react/src/api/oauth-popup.ts
@@ -85,6 +85,7 @@ export const openOAuthPopup = <TAuth>(input: OpenOAuthPopupInput<TAuth>): (() =>
   /** Close the popup window if it's still open. Swallows cross-origin errors. */
   const closePopup = (popup: Window | null) => {
     if (!popup) return;
+    // oxlint-disable-next-line executor/no-try-catch-or-throw -- boundary: cross-origin popup state can throw and cleanup is best-effort
     try {
       if (!popup.closed) popup.close();
     } catch {
@@ -129,6 +130,7 @@ export const openOAuthPopup = <TAuth>(input: OpenOAuthPopupInput<TAuth>): (() =>
   const pollMs = input.closedPollMs ?? 500;
   pollHandle = setInterval(() => {
     let isClosed = false;
+    // oxlint-disable-next-line executor/no-try-catch-or-throw -- boundary: browser popup.closed can throw while navigating cross-origin
     try {
       isClosed = popup.closed;
     } catch {
diff --git a/packages/react/src/api/optimistic.tsx b/packages/react/src/api/optimistic.tsx
index 3af368adf..fa1ccddfb 100644
--- a/packages/react/src/api/optimistic.tsx
+++ b/packages/react/src/api/optimistic.tsx
@@ -176,7 +176,7 @@ export const useConnectionsWithPendingRemovals = (scopeId: ScopeId) => {
     if (!AsyncResult.isSuccess(result) || pending.length === 0) return;
 
     const serverIds = new Set(
-      result.value.map((connection: { readonly id: string }) => connection.id as string),
+      result.value.map((connection: { readonly id: string }) => connection.id),
     );
     for (const entry of pending) {
       if (!serverIds.has(entry.id)) remove(entry.id);
@@ -189,7 +189,7 @@ export const useConnectionsWithPendingRemovals = (scopeId: ScopeId) => {
         if (pending.length === 0) return connections;
         const hiddenIds = new Set(pending.map((entry) => entry.id));
         return connections.filter(
-          (connection: { readonly id: string }) => !hiddenIds.has(connection.id as string),
+          (connection: { readonly id: string }) => !hiddenIds.has(connection.id),
         );
       }),
     [result, pending],
diff --git a/packages/react/src/components/form.tsx b/packages/react/src/components/form.tsx
index 0830633aa..059dc187f 100644
--- a/packages/react/src/components/form.tsx
+++ b/packages/react/src/components/form.tsx
@@ -120,6 +120,7 @@ function FormDescription({ className, ...props }: React.ComponentProps<"p">) {
 
 function FormMessage({ className, ...props }: React.ComponentProps<"p">) {
   const { error, formMessageId } = useFormField();
+  // oxlint-disable-next-line executor/no-unknown-error-message -- boundary: react-hook-form field errors carry public validation text
   const body = error ? String(error?.message ?? "") : props.children;
 
   if (!body) {
diff --git a/packages/react/src/pages/policies.tsx b/packages/react/src/pages/policies.tsx
index ca7bfe694..8b712f6d7 100644
--- a/packages/react/src/pages/policies.tsx
+++ b/packages/react/src/pages/policies.tsx
@@ -1,6 +1,7 @@
 import { useState } from "react";
 import { useAtomSet, useAtomValue } from "@effect/atom-react";
 import * as AsyncResult from "effect/unstable/reactivity/AsyncResult";
+import * as Exit from "effect/Exit";
 import { generateKeyBetween } from "fractional-indexing";
 import { ChevronDownIcon } from "lucide-react";
 import { PolicyId, type ToolPolicyAction } from "@executor-js/sdk";
@@ -253,7 +254,7 @@ export function PoliciesPage() {
   const scopeId = useScope();
   const policies = useAtomValue(policiesOptimisticAtom(scopeId));
   const doCreate = useAtomSet(createPolicyOptimistic(scopeId), {
-    mode: "promise",
+    mode: "promiseExit",
   });
   const doUpdate = useAtomSet(updatePolicyOptimistic(scopeId), {
     mode: "promise",
@@ -265,15 +266,16 @@ export function PoliciesPage() {
 
   const handleCreate = async (input: { pattern: string; action: ToolPolicyAction }) => {
     setBusy(true);
-    try {
-      await doCreate({
-        params: { scopeId },
-        payload: { pattern: input.pattern, action: input.action },
-        reactivityKeys: policyWriteKeys,
-      });
-    } finally {
+    const exit = await doCreate({
+      params: { scopeId },
+      payload: { pattern: input.pattern, action: input.action },
+      reactivityKeys: policyWriteKeys,
+    });
+    if (Exit.isFailure(exit)) {
       setBusy(false);
+      return;
     }
+    setBusy(false);
   };
 
   const handleUpdate = async (id: string, action: ToolPolicyAction) => {
diff --git a/packages/react/src/pages/source-detail.tsx b/packages/react/src/pages/source-detail.tsx
index 7436b42cf..049d79037 100644
--- a/packages/react/src/pages/source-detail.tsx
+++ b/packages/react/src/pages/source-detail.tsx
@@ -2,6 +2,7 @@ import { Suspense, useEffect, useMemo, useState } from "react";
 import { useNavigate } from "@tanstack/react-router";
 import { useAtomValue, useAtomSet, useAtomRefresh } from "@effect/atom-react";
 import * as AsyncResult from "effect/unstable/reactivity/AsyncResult";
+import * as Exit from "effect/Exit";
 import { effectivePolicyFromSorted } from "@executor-js/sdk";
 import {
   policiesOptimisticAtom,
@@ -31,8 +32,8 @@ export function SourceDetailPage(props: { namespace: string }) {
   const policies = useAtomValue(policiesOptimisticAtom(scopeId));
   const refreshSources = useAtomRefresh(sourcesAtom(scopeId));
   const refreshTools = useAtomRefresh(sourceToolsAtom(namespace, scopeId));
-  const doRemove = useAtomSet(removeSource, { mode: "promise" });
-  const doRefresh = useAtomSet(refreshSource, { mode: "promise" });
+  const doRemove = useAtomSet(removeSource, { mode: "promiseExit" });
+  const doRefresh = useAtomSet(refreshSource, { mode: "promiseExit" });
   const policyActions = usePolicyActions(scopeId);
   const navigate = useNavigate();
 
@@ -117,28 +118,25 @@ export function SourceDetailPage(props: { namespace: string }) {
 
   const handleDelete = async () => {
     setDeleting(true);
-    try {
-      await doRemove({
-        params: { scopeId, sourceId: namespace },
-        reactivityKeys: sourceWriteKeys,
-      });
-      void navigate({ to: "/" });
-    } catch {
+    const exit = await doRemove({
+      params: { scopeId, sourceId: namespace },
+      reactivityKeys: sourceWriteKeys,
+    });
+    if (Exit.isFailure(exit)) {
       setDeleting(false);
       setConfirmDelete(false);
+      return;
     }
+    void navigate({ to: "/" });
   };
 
   const handleRefresh = async () => {
     setRefreshing(true);
-    try {
-      await doRefresh({
-        params: { scopeId, sourceId: namespace },
-        reactivityKeys: sourceWriteKeys,
-      });
-    } finally {
-      setRefreshing(false);
-    }
+    await doRefresh({
+      params: { scopeId, sourceId: namespace },
+      reactivityKeys: sourceWriteKeys,
+    });
+    setRefreshing(false);
   };
 
   const handleEditSave = () => {
diff --git a/packages/react/src/pages/sources.tsx b/packages/react/src/pages/sources.tsx
index a69924588..c4e26fab6 100644
--- a/packages/react/src/pages/sources.tsx
+++ b/packages/react/src/pages/sources.tsx
@@ -2,6 +2,7 @@ import { Suspense, useCallback, useMemo, useState } from "react";
 import { Link, useNavigate } from "@tanstack/react-router";
 import { useAtomSet } from "@effect/atom-react";
 import * as AsyncResult from "effect/unstable/reactivity/AsyncResult";
+import * as Exit from "effect/Exit";
 import { PlusIcon } from "lucide-react";
 import type { SourceDetectionResult } from "@executor-js/sdk";
 import {
@@ -138,7 +139,7 @@ const looksLikeUrl = (raw: string): boolean => {
 function ConnectDialog(props: { open: boolean; onOpenChange: (open: boolean) => void }) {
   const sourcePlugins = useSourcePlugins();
   const scopeId = useScope();
-  const doDetect = useAtomSet(detectSource, { mode: "promise" });
+  const doDetect = useAtomSet(detectSource, { mode: "promiseExit" });
   const navigate = useNavigate();
 
   const [query, setQuery] = useState("");
@@ -160,37 +161,38 @@ function ConnectDialog(props: { open: boolean; onOpenChange: (open: boolean) =>
     if (!trimmed) return;
     setDetecting(true);
     setError(null);
-    try {
-      const results = await doDetect({
-        params: { scopeId },
-        payload: { url: trimmed },
-      });
-      if (results.length === 0) {
-        setError("Could not detect a source type from this URL. Try adding manually.");
-        setDetecting(false);
-        return;
-      }
-      const detected = bestDetection(results);
-      if (!detected) {
-        setError("Could not detect a source type from this URL. Try adding manually.");
-        setDetecting(false);
-        return;
-      }
-      const pluginKey = KIND_TO_PLUGIN_KEY[detected.kind];
-      if (pluginKey) {
-        closeAndReset();
-        void navigate({
-          to: "/sources/add/$pluginKey",
-          params: { pluginKey },
-          search: { url: trimmed, namespace: detected.namespace },
-        });
-      } else {
-        setError(`Detected source type "${detected.kind}" but no plugin is available for it.`);
-        setDetecting(false);
-      }
-    } catch {
+    const exit = await doDetect({
+      params: { scopeId },
+      payload: { url: trimmed },
+    });
+    if (Exit.isFailure(exit)) {
       setError("Detection failed. Try adding a source manually.");
       setDetecting(false);
+      return;
+    }
+    const results = exit.value;
+    if (results.length === 0) {
+      setError("Could not detect a source type from this URL. Try adding manually.");
+      setDetecting(false);
+      return;
+    }
+    const detected = bestDetection(results);
+    if (!detected) {
+      setError("Could not detect a source type from this URL. Try adding manually.");
+      setDetecting(false);
+      return;
+    }
+    const pluginKey = KIND_TO_PLUGIN_KEY[detected.kind];
+    if (pluginKey) {
+      closeAndReset();
+      void navigate({
+        to: "/sources/add/$pluginKey",
+        params: { pluginKey },
+        search: { url: trimmed, namespace: detected.namespace },
+      });
+    } else {
+      setError(`Detected source type "${detected.kind}" but no plugin is available for it.`);
+      setDetecting(false);
     }
   }, [query, doDetect, navigate, scopeId, closeAndReset]);