diff --git a/docs/google-claim-mapping.md b/docs/google-claim-mapping.md
new file mode 100644
index 0000000..4998447
--- /dev/null
+++ b/docs/google-claim-mapping.md
@@ -0,0 +1,23 @@
+# Google claim and identity mapping
+
+The broker uses the upstream OIDC `sub` as the stable federated identity key.
+Email is a mutable profile attribute and is never the external identity key.
+
+The default mapping policy is:
+
+| Upstream claim | Keycloak target |
+|---|---|
+| `sub` | stable username `${ALIAS}.${CLAIM.sub}` and federated identity ID |
+| `email` | email |
+| `given_name` | first name |
+| `family_name` | last name |
+| `picture` | custom `picture` attribute |
+| `hd` | custom `hd` attribute |
+
+The Identity Provider uses `syncMode=IMPORT`: profile values are imported on
+first login and later local edits are not overwritten on every login. `FORCE`
+is an explicit alternative when upstream freshness is more important.
+
+`./scripts/verify-google-claim-mapping.sh` signs in through the controllable
+OIDC realm and verifies the resulting Keycloak user, custom attributes, stable
+subject-derived username, and federated identity record.
diff --git a/google-e2e/claim-mapping.mjs b/google-e2e/claim-mapping.mjs
new file mode 100644
index 0000000..9be4c2a
--- /dev/null
+++ b/google-e2e/claim-mapping.mjs
@@ -0,0 +1,123 @@
+import assert from "node:assert/strict";
+import { chromium } from "playwright-core";
+
+const keycloakUrl = process.env.KEYCLOAK_URL ?? "http://localhost:8080";
+const adminUsername = process.env.KC_BOOTSTRAP_ADMIN_USERNAME;
+const adminPassword = process.env.KC_BOOTSTRAP_ADMIN_PASSWORD;
+const mockPassword = process.env.MOCK_GOOGLE_USER_PASSWORD;
+assert.ok(adminUsername && adminPassword && mockPassword);
+
+async function adminToken() {
+  const response = await fetch(
+    `${keycloakUrl}/realms/master/protocol/openid-connect/token`,
+    {
+      method: "POST",
+      body: new URLSearchParams({
+        client_id: "admin-cli",
+        grant_type: "password",
+        username: adminUsername,
+        password: adminPassword,
+      }),
+    },
+  );
+  assert.equal(response.status, 200);
+  return (await response.json()).access_token;
+}
+
+async function usersByEmail(token) {
+  const response = await fetch(
+    `${keycloakUrl}/admin/realms/keycloak-patterns/users?email=${encodeURIComponent(
+      "broker-new-user@example.test",
+    )}&exact=true`,
+    { headers: { Authorization: `Bearer ${token}` } },
+  );
+  assert.equal(response.status, 200);
+  return response.json();
+}
+
+async function userById(token, userId) {
+  const response = await fetch(
+    `${keycloakUrl}/admin/realms/keycloak-patterns/users/${userId}`,
+    { headers: { Authorization: `Bearer ${token}` } },
+  );
+  assert.equal(response.status, 200);
+  return response.json();
+}
+
+async function removePreviousUser(token) {
+  for (const user of await usersByEmail(token)) {
+    const response = await fetch(
+      `${keycloakUrl}/admin/realms/keycloak-patterns/users/${user.id}`,
+      {
+        method: "DELETE",
+        headers: { Authorization: `Bearer ${token}` },
+      },
+    );
+    assert.equal(response.status, 204);
+  }
+}
+
+async function brokerLogin(page) {
+  const url = new URL(
+    `${keycloakUrl}/realms/keycloak-patterns/protocol/openid-connect/auth`,
+  );
+  url.search = new URLSearchParams({
+    client_id: "spa-public",
+    redirect_uri: "http://localhost:8088/",
+    response_type: "code",
+    scope: "openid profile email",
+    state: crypto.randomUUID(),
+    nonce: crypto.randomUUID(),
+    code_challenge: "K2qUEfBl-nQvF2gB4dNxC2zYVwZc1CVnZb5CsX2L7fI",
+    code_challenge_method: "S256",
+    kc_idp_hint: "mock-google",
+    prompt: "login",
+  });
+  await page.goto(url.toString());
+  await page.waitForURL(/\/realms\/mock-google\//u);
+  await page.locator("#username").fill("mock-new-user");
+  await page.locator("#password").fill(mockPassword);
+  await page.locator("#kc-login").click();
+  await page.waitForURL(/localhost:8088\/\?.*code=/u);
+}
+
+const token = await adminToken();
+await removePreviousUser(token);
+
+const browser = await chromium.launch({
+  executablePath: process.env.CHROME_BIN ?? "/usr/bin/google-chrome",
+  headless: true,
+  args: ["--no-sandbox"],
+});
+
+try {
+  const page = await browser.newPage();
+  await brokerLogin(page);
+
+  const users = await usersByEmail(token);
+  assert.equal(users.length, 1);
+  const user = await userById(token, users[0].id);
+  assert.match(user.username, /^mock-google\.[0-9a-f-]+$/u);
+  assert.equal(user.firstName, "Broker");
+  assert.equal(user.lastName, "New");
+  assert.deepEqual(user.attributes.picture, [
+    "https://images.example.test/mock-user.png",
+  ]);
+  assert.deepEqual(user.attributes.hd, ["example.test"]);
+
+  const identitiesResponse = await fetch(
+    `${keycloakUrl}/admin/realms/keycloak-patterns/users/${user.id}/federated-identity`,
+    { headers: { Authorization: `Bearer ${token}` } },
+  );
+  assert.equal(identitiesResponse.status, 200);
+  const identities = await identitiesResponse.json();
+  assert.equal(identities.length, 1);
+  assert.equal(identities[0].identityProvider, "mock-google");
+  assert.ok(identities[0].userId);
+
+  console.log(
+    "Google claim mapping verified: stable sub username, profile attributes, federated identity",
+  );
+} finally {
+  await browser.close();
+}
diff --git a/google-e2e/package.json b/google-e2e/package.json
index 5727e22..9be0821 100644
--- a/google-e2e/package.json
+++ b/google-e2e/package.json
@@ -4,7 +4,8 @@
   "private": true,
   "type": "module",
   "scripts": {
-    "test:first-broker": "node first-broker-login.mjs"
+    "test:first-broker": "node first-broker-login.mjs",
+    "test:claim-mapping": "node claim-mapping.mjs"
   },
   "dependencies": {
     "playwright-core": "1.55.1"
diff --git a/keycloak/import/keycloak-patterns-realm.json b/keycloak/import/keycloak-patterns-realm.json
index c6acf67..e45a188 100644
--- a/keycloak/import/keycloak-patterns-realm.json
+++ b/keycloak/import/keycloak-patterns-realm.json
@@ -170,6 +170,67 @@
       }
     }
   ],
+  "identityProviderMappers": [
+    {
+      "name": "mock-google-stable-username",
+      "identityProviderAlias": "mock-google",
+      "identityProviderMapper": "oidc-username-idp-mapper",
+      "config": {
+        "template": "${ALIAS}.${CLAIM.sub}",
+        "target": "LOCAL"
+      }
+    },
+    {
+      "name": "mock-google-email",
+      "identityProviderAlias": "mock-google",
+      "identityProviderMapper": "oidc-user-attribute-idp-mapper",
+      "config": {
+        "syncMode": "INHERIT",
+        "claim": "email",
+        "user.attribute": "email"
+      }
+    },
+    {
+      "name": "mock-google-given-name",
+      "identityProviderAlias": "mock-google",
+      "identityProviderMapper": "oidc-user-attribute-idp-mapper",
+      "config": {
+        "syncMode": "INHERIT",
+        "claim": "given_name",
+        "user.attribute": "firstName"
+      }
+    },
+    {
+      "name": "mock-google-family-name",
+      "identityProviderAlias": "mock-google",
+      "identityProviderMapper": "oidc-user-attribute-idp-mapper",
+      "config": {
+        "syncMode": "INHERIT",
+        "claim": "family_name",
+        "user.attribute": "lastName"
+      }
+    },
+    {
+      "name": "mock-google-picture",
+      "identityProviderAlias": "mock-google",
+      "identityProviderMapper": "oidc-user-attribute-idp-mapper",
+      "config": {
+        "syncMode": "INHERIT",
+        "claim": "picture",
+        "user.attribute": "picture"
+      }
+    },
+    {
+      "name": "mock-google-hosted-domain",
+      "identityProviderAlias": "mock-google",
+      "identityProviderMapper": "oidc-user-attribute-idp-mapper",
+      "config": {
+        "syncMode": "INHERIT",
+        "claim": "hd",
+        "user.attribute": "hd"
+      }
+    }
+  ],
   "users": [
     {
       "username": "admin-user",
diff --git a/keycloak/import/mock-google-realm.json b/keycloak/import/mock-google-realm.json
index 8ad4f8f..0b49b07 100644
--- a/keycloak/import/mock-google-realm.json
+++ b/keycloak/import/mock-google-realm.json
@@ -25,7 +25,37 @@
       "redirectUris": [
         "http://localhost:8080/realms/keycloak-patterns/broker/mock-google/endpoint"
       ],
-      "webOrigins": []
+      "webOrigins": [],
+      "protocolMappers": [
+        {
+          "name": "hosted-domain",
+          "protocol": "openid-connect",
+          "protocolMapper": "oidc-hardcoded-claim-mapper",
+          "consentRequired": false,
+          "config": {
+            "claim.name": "hd",
+            "claim.value": "example.test",
+            "jsonType.label": "String",
+            "id.token.claim": "true",
+            "access.token.claim": "true",
+            "userinfo.token.claim": "true"
+          }
+        },
+        {
+          "name": "picture",
+          "protocol": "openid-connect",
+          "protocolMapper": "oidc-hardcoded-claim-mapper",
+          "consentRequired": false,
+          "config": {
+            "claim.name": "picture",
+            "claim.value": "https://images.example.test/mock-user.png",
+            "jsonType.label": "String",
+            "id.token.claim": "true",
+            "access.token.claim": "true",
+            "userinfo.token.claim": "true"
+          }
+        }
+      ]
     }
   ],
   "users": [
@@ -51,14 +81,6 @@
       "emailVerified": false,
       "firstName": "Broker",
       "lastName": "Collision",
-      "attributes": {
-        "hd": [
-          "example.test"
-        ],
-        "picture": [
-          "https://images.example.test/mock-collision-user.png"
-        ]
-      },
       "credentials": [
         {
           "type": "password",
diff --git a/scripts/configure-broker-user-profile.sh b/scripts/configure-broker-user-profile.sh
new file mode 100755
index 0000000..e07764f
--- /dev/null
+++ b/scripts/configure-broker-user-profile.sh
@@ -0,0 +1,58 @@
+#!/usr/bin/env sh
+set -eu
+
+if [ ! -f .env ]; then
+  echo "missing .env" >&2
+  exit 1
+fi
+
+set -a
+. ./.env
+set +a
+
+keycloak_url="${KEYCLOAK_URL:-http://localhost:8080}"
+realm="${KEYCLOAK_REALM:-keycloak-patterns}"
+profile_url="$keycloak_url/admin/realms/$realm/users/profile"
+
+admin_token="$(
+  curl -fsS \
+    -d client_id=admin-cli \
+    -d grant_type=password \
+    -d "username=$KC_BOOTSTRAP_ADMIN_USERNAME" \
+    -d "password=$KC_BOOTSTRAP_ADMIN_PASSWORD" \
+    "$keycloak_url/realms/master/protocol/openid-connect/token" |
+    jq -er .access_token
+)"
+
+profile="$(curl -fsS -H "Authorization: Bearer $admin_token" "$profile_url")"
+updated_profile="$(
+  printf '%s' "$profile" |
+    jq '
+      def broker_attribute($name; $label): {
+        name: $name,
+        displayName: $label,
+        validations: {length: {max: 2048}},
+        permissions: {
+          view: ["admin", "user"],
+          edit: ["admin"]
+        },
+        multivalued: false,
+        group: "user-metadata"
+      };
+      if any(.attributes[]; .name == "picture") then .
+      else .attributes += [broker_attribute("picture"; "Profile picture URL")]
+      end |
+      if any(.attributes[]; .name == "hd") then .
+      else .attributes += [broker_attribute("hd"; "Hosted domain")]
+      end
+    '
+)"
+
+printf '%s' "$updated_profile" |
+  curl -fsS -X PUT \
+    -H "Authorization: Bearer $admin_token" \
+    -H "Content-Type: application/json" \
+    --data @- \
+    "$profile_url"
+
+echo "Broker user-profile attributes configured for realm '$realm'"
diff --git a/scripts/configure-google-idp.sh b/scripts/configure-google-idp.sh
index dcbddd9..b39ffb8 100755
--- a/scripts/configure-google-idp.sh
+++ b/scripts/configure-google-idp.sh
@@ -15,6 +15,8 @@ set +a
 : "${GOOGLE_CLIENT_ID:?set GOOGLE_CLIENT_ID in .env}"
 : "${GOOGLE_CLIENT_SECRET:?set GOOGLE_CLIENT_SECRET in .env}"
 
+./scripts/configure-broker-user-profile.sh
+
 keycloak_url="${KEYCLOAK_URL:-http://localhost:8080}"
 realm="${KEYCLOAK_REALM:-keycloak-patterns}"
 
@@ -76,6 +78,73 @@ else
   action="created"
 fi
 
+mapper_endpoint="$endpoint/google/mappers"
+upsert_mapper() {
+  mapper_name="$1"
+  mapper_type="$2"
+  mapper_config="$3"
+  mapper_id="$(
+    curl -fsS \
+      -H "Authorization: Bearer $admin_token" \
+      "$mapper_endpoint" |
+      jq -r --arg name "$mapper_name" '
+        .[] | select(.name == $name) | .id
+      ' |
+      head -1
+  )"
+  mapper_payload="$(
+    jq -n \
+      --arg name "$mapper_name" \
+      --arg alias "google" \
+      --arg mapper "$mapper_type" \
+      --argjson config "$mapper_config" \
+      '{
+        name: $name,
+        identityProviderAlias: $alias,
+        identityProviderMapper: $mapper,
+        config: $config
+      }'
+  )"
+  if [ -n "$mapper_id" ]; then
+    curl -fsS -X PUT \
+      -H "Authorization: Bearer $admin_token" \
+      -H "Content-Type: application/json" \
+      --data "$mapper_payload" \
+      "$mapper_endpoint/$mapper_id"
+  else
+    curl -fsS -X POST \
+      -H "Authorization: Bearer $admin_token" \
+      -H "Content-Type: application/json" \
+      --data "$mapper_payload" \
+      "$mapper_endpoint"
+  fi
+}
+
+upsert_mapper \
+  "google-stable-username" \
+  "oidc-username-idp-mapper" \
+  '{"template":"${ALIAS}.${CLAIM.sub}","target":"LOCAL"}'
+upsert_mapper \
+  "google-email" \
+  "oidc-user-attribute-idp-mapper" \
+  '{"syncMode":"INHERIT","claim":"email","user.attribute":"email"}'
+upsert_mapper \
+  "google-given-name" \
+  "oidc-user-attribute-idp-mapper" \
+  '{"syncMode":"INHERIT","claim":"given_name","user.attribute":"firstName"}'
+upsert_mapper \
+  "google-family-name" \
+  "oidc-user-attribute-idp-mapper" \
+  '{"syncMode":"INHERIT","claim":"family_name","user.attribute":"lastName"}'
+upsert_mapper \
+  "google-picture" \
+  "oidc-user-attribute-idp-mapper" \
+  '{"syncMode":"INHERIT","claim":"picture","user.attribute":"picture"}'
+upsert_mapper \
+  "google-hosted-domain" \
+  "oidc-user-attribute-idp-mapper" \
+  '{"syncMode":"INHERIT","claim":"hd","user.attribute":"hd"}'
+
 echo "Google Identity Provider $action for realm '$realm'"
 echo "Register this exact Google redirect URI:"
 echo "$keycloak_url/realms/$realm/broker/google/endpoint"
diff --git a/scripts/verify-google-claim-mapping.sh b/scripts/verify-google-claim-mapping.sh
new file mode 100755
index 0000000..ad90ea1
--- /dev/null
+++ b/scripts/verify-google-claim-mapping.sh
@@ -0,0 +1,16 @@
+#!/usr/bin/env sh
+set -eu
+
+if [ ! -f .env ]; then
+  echo "missing .env" >&2
+  exit 1
+fi
+
+set -a
+. ./.env
+set +a
+
+./scripts/configure-broker-user-profile.sh
+./scripts/set-first-broker-login-mode.sh secure
+npm --prefix google-e2e ci
+npm --prefix google-e2e run test:claim-mapping