diff --git a/web/src/lib/env-state.test.ts b/web/src/lib/env-state.test.ts
new file mode 100644
index 0000000000..176b57aa47
--- /dev/null
+++ b/web/src/lib/env-state.test.ts
@@ -0,0 +1,44 @@
+import { describe, expect, it } from "vitest";
+
+import type { EnvVarInfo } from "./api";
+import { removeDeletedEnvVarFromState } from "./env-state";
+
+function envVar(overrides: Partial<EnvVarInfo> = {}): EnvVarInfo {
+  return {
+    is_set: true,
+    redacted_value: "secr...alue",
+    description: "",
+    url: null,
+    category: "provider",
+    is_password: true,
+    tools: [],
+    advanced: false,
+    ...overrides,
+  };
+}
+
+describe("removeDeletedEnvVarFromState", () => {
+  it("removes a deleted custom key from dashboard state", () => {
+    const vars = {
+      WHATSAPP_DEBUG: envVar({ category: "custom", custom: true }),
+      OPENAI_API_KEY: envVar(),
+    };
+
+    const updated = removeDeletedEnvVarFromState(vars, "WHATSAPP_DEBUG");
+
+    expect(updated).not.toHaveProperty("WHATSAPP_DEBUG");
+    expect(updated?.OPENAI_API_KEY).toBe(vars.OPENAI_API_KEY);
+  });
+
+  it("keeps a catalog key available while marking it unset", () => {
+    const vars = { OPENAI_API_KEY: envVar() };
+
+    const updated = removeDeletedEnvVarFromState(vars, "OPENAI_API_KEY");
+
+    expect(updated?.OPENAI_API_KEY).toEqual({
+      ...vars.OPENAI_API_KEY,
+      is_set: false,
+      redacted_value: null,
+    });
+  });
+});
diff --git a/web/src/lib/env-state.ts b/web/src/lib/env-state.ts
new file mode 100644
index 0000000000..3116be949f
--- /dev/null
+++ b/web/src/lib/env-state.ts
@@ -0,0 +1,21 @@
+import type { EnvVarInfo } from "./api";
+
+/** Reconcile a successful DELETE /api/env response with the Keys page state. */
+export function removeDeletedEnvVarFromState(
+  vars: Record<string, EnvVarInfo> | null,
+  key: string,
+): Record<string, EnvVarInfo> | null {
+  const info = vars?.[key];
+  if (!vars || !info) return vars;
+
+  if (info.custom) {
+    const updated = { ...vars };
+    delete updated[key];
+    return updated;
+  }
+
+  return {
+    ...vars,
+    [key]: { ...info, is_set: false, redacted_value: null },
+  };
+}
diff --git a/web/src/pages/EnvPage.tsx b/web/src/pages/EnvPage.tsx
index edcc45844c..78e2266fed 100644
--- a/web/src/pages/EnvPage.tsx
+++ b/web/src/pages/EnvPage.tsx
@@ -17,6 +17,7 @@ import {
 } from "lucide-react";
 import { api } from "@/lib/api";
 import type { EnvVarInfo } from "@/lib/api";
+import { removeDeletedEnvVarFromState } from "@/lib/env-state";
 import { DeleteConfirmDialog } from "@/components/DeleteConfirmDialog";
 import { Toast } from "@nous-research/ui/ui/components/toast";
 import { useConfirmDelete } from "@nous-research/ui/hooks/use-confirm-delete";
@@ -722,14 +723,7 @@ export default function EnvPage() {
         setSaving(key);
         try {
           await api.deleteEnvVar(key);
-          setVars((prev) =>
-            prev
-              ? {
-                  ...prev,
-                  [key]: { ...prev[key], is_set: false, redacted_value: null },
-                }
-              : prev,
-          );
+          setVars((prev) => removeDeletedEnvVarFromState(prev, key));
           setEdits((prev) => {
             const n = { ...prev };
             delete n[key];