diff --git a/locales/index.d.ts b/locales/index.d.ts
index 7f20c6803f..d6344405b5 100644
--- a/locales/index.d.ts
+++ b/locales/index.d.ts
@@ -7802,6 +7802,10 @@ export interface Locale extends ILocale {
          * This condition may be incorrect for remote users.
          */
         "remoteDataWarning": string;
+        /**
+         * Select a user to test the condition.
+         */
+        "selectTestUser": string;
     };
     "_sensitiveMediaDetection": {
         /**
diff --git a/packages/backend/src/core/RoleService.ts b/packages/backend/src/core/RoleService.ts
index afaa645383..6429e304e5 100644
--- a/packages/backend/src/core/RoleService.ts
+++ b/packages/backend/src/core/RoleService.ts
@@ -356,6 +356,39 @@ export class RoleService implements OnApplicationShutdown, OnModuleInit {
 		}
 	}
 
+	@bindThis
+	public annotateCond(user: MiUser, roles: MiRole[], value: RoleCondFormulaValue, followStats: FollowStats, results: { [k: string]: boolean }): boolean {
+		let result: boolean;
+		try {
+			switch (value.type) {
+				case 'and': {
+					result = true;
+					// Don't use every(), since that short-circuits.
+					// We need to run annotateCond() on every condition.
+					value.values.forEach(v => result = this.annotateCond(user, roles, v, followStats, results) && result);
+					break;
+				}
+				case 'or': {
+					result = false;
+					value.values.forEach(v => result = this.annotateCond(user, roles, v, followStats, results) || result);
+					break;
+				}
+				case 'not': {
+					result = !this.annotateCond(user, roles, value.value, followStats, results);
+					break;
+				}
+				default: {
+					result = this.evalCond(user, roles, value, followStats);
+				}
+			}
+		} catch (err) {
+			// TODO: log error
+			result = false;
+		}
+		results[value.id] = result;
+		return result;
+	}
+
 	@bindThis
 	public async getRoles() {
 		const roles = await this.rolesCache.fetch(() => this.rolesRepository.findBy({}));
diff --git a/packages/backend/src/server/api/endpoint-list.ts b/packages/backend/src/server/api/endpoint-list.ts
index 962055052d..521710bc13 100644
--- a/packages/backend/src/server/api/endpoint-list.ts
+++ b/packages/backend/src/server/api/endpoint-list.ts
@@ -86,6 +86,7 @@ export * as 'admin/relays/list' from './endpoints/admin/relays/list.js';
 export * as 'admin/relays/remove' from './endpoints/admin/relays/remove.js';
 export * as 'admin/reset-password' from './endpoints/admin/reset-password.js';
 export * as 'admin/resolve-abuse-user-report' from './endpoints/admin/resolve-abuse-user-report.js';
+export * as 'admin/roles/annotate-condition' from './endpoints/admin/roles/annotate-condition.js';
 export * as 'admin/roles/assign' from './endpoints/admin/roles/assign.js';
 export * as 'admin/roles/create' from './endpoints/admin/roles/create.js';
 export * as 'admin/roles/clone' from './endpoints/admin/roles/clone.js';
diff --git a/packages/backend/src/server/api/endpoints/admin/roles/annotate-condition.ts b/packages/backend/src/server/api/endpoints/admin/roles/annotate-condition.ts
new file mode 100644
index 0000000000..aa8cdd5139
--- /dev/null
+++ b/packages/backend/src/server/api/endpoints/admin/roles/annotate-condition.ts
@@ -0,0 +1,71 @@
+/*
+ * SPDX-FileCopyrightText: bunnybeam and other Sharkey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { Inject, Injectable } from '@nestjs/common';
+import { Endpoint } from '@/server/api/endpoint-base.js';
+import type { UsersRepository } from '@/models/_.js';
+import { DI } from '@/di-symbols.js';
+import { ApiError } from '@/server/api/error.js';
+import { RoleService } from '@/core/RoleService.js';
+import { CacheService } from '@/core/CacheService.js';
+
+export const meta = {
+	tags: ['admin', 'role'],
+
+	requireCredential: true,
+	requireModerator: true,
+	kind: 'read:admin:roles',
+
+	errors: {
+		noSuchUser: {
+			message: 'No such user.',
+			code: 'NO_SUCH_USER',
+			id: '34550050-3115-4443-b389-ce3e62eb9857',
+		},
+	},
+
+	res: {
+		type: 'object',
+		optional: false, nullable: false,
+		additionalProperties: { type: 'boolean' },
+	},
+} as const;
+
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+		condFormula: { type: 'object' },
+	},
+	required: [
+		'userId',
+		'condFormula',
+	],
+} as const;
+
+@Injectable()
+export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-disable-line import/no-default-export
+	constructor(
+		@Inject(DI.usersRepository)
+		private usersRepository: UsersRepository,
+
+		private roleService: RoleService,
+		private cacheService: CacheService,
+	) {
+		super(meta, paramDef, async (ps) => {
+			const user = await this.usersRepository.findOneBy({ id: ps.userId });
+			if (user === null) {
+				throw new ApiError(meta.errors.noSuchUser);
+			}
+			const followStats = await this.cacheService.getFollowStats(ps.userId);
+			const roles = await this.roleService.getUserRoles(ps.userId);
+
+			const results: { [k: string]: boolean } = {};
+			roleService.annotateCond(user, roles, ps.condFormula, followStats, results);
+			return results;
+		});
+	}
+}
+
diff --git a/packages/frontend/src/pages/admin/RolesEditorFormula.vue b/packages/frontend/src/pages/admin/RolesEditorFormula.vue
index b7375b0faf..680f7902a3 100644
--- a/packages/frontend/src/pages/admin/RolesEditorFormula.vue
+++ b/packages/frontend/src/pages/admin/RolesEditorFormula.vue
@@ -6,6 +6,10 @@ SPDX-License-Identifier: AGPL-3.0-only
 <template>
 <div class="_gaps">
 	<div :class="$style.header">
+		<div style="display: flex; align-items: center;">
+			<i v-if="results !== null && results[v.id]" class="ti ti-check" :class="$style.testResultTrue"></i>
+			<i v-else-if="results !== null" class="ti ti-x" :class="$style.testResultFalse"></i>
+		</div>
 		<MkSelect v-model="type" :class="$style.typeSelect">
 			<option value="isLocal">{{ i18n.ts._role._condition.isLocal }}</option>
 			<option value="isRemote">{{ i18n.ts._role._condition.isRemote }}</option>
@@ -50,7 +54,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 			<template #item="{element}">
 				<div :class="$style.item">
 					<!-- divが無いとエラーになる https://github.com/SortableJS/vue.draggable.next/issues/189 -->
-					<RolesEditorFormula :modelValue="element" draggable @update:modelValue="updated => valuesItemUpdated(updated)" @remove="removeItem(element)"/>
+					<RolesEditorFormula :modelValue="element" :results="results" draggable @update:modelValue="updated => valuesItemUpdated(updated)" @remove="removeItem(element)"/>
 				</div>
 			</template>
 		</Sortable>
@@ -58,7 +62,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 	</div>
 
 	<div v-else-if="type === 'not'" :class="$style.item">
-		<RolesEditorFormula v-model="v.value"/>
+		<RolesEditorFormula v-model="v.value" :results="results"/>
 	</div>
 
 	<MkInput v-else-if="type === 'createdLessThan' || type === 'createdMoreThan'" v-model="v.sec" type="number">
@@ -127,6 +131,7 @@ const emit = defineEmits<{
 const props = defineProps<{
 	modelValue: any;
 	draggable?: boolean;
+	results: object | null;
 }>();
 
 const v = ref(deepClone(props.modelValue));
@@ -229,4 +234,16 @@ function removeSelf() {
 		margin-right: 4px;
 	}
 }
+
+.testResultFalse {
+	color: var(--MI_THEME-error);
+	align-self: center;
+	margin-right: 10px;
+}
+
+.testResultTrue {
+	color: var(--MI_THEME-success);
+	align-self: center;
+	margin-right: 10px;
+}
 </style>
diff --git a/packages/frontend/src/pages/admin/roles.editor.vue b/packages/frontend/src/pages/admin/roles.editor.vue
index b15c9ad51b..a75f9e6567 100644
--- a/packages/frontend/src/pages/admin/roles.editor.vue
+++ b/packages/frontend/src/pages/admin/roles.editor.vue
@@ -48,7 +48,39 @@ SPDX-License-Identifier: AGPL-3.0-only
 	<MkFolder v-if="role.target === 'conditional'" defaultOpen>
 		<template #label>{{ i18n.ts._role.condition }}</template>
 		<div class="_gaps">
-			<RolesEditorFormula v-model="role.condFormula"/>
+			<RolesEditorFormula v-model="role.condFormula" :results="conditionResults"/>
+			<div>
+				<div :class="$style.userSelectLabel">{{ i18n.ts._role.selectTestUser }}</div>
+				<MkButton
+					v-if="conditionTestUser == null"
+					transparent
+					:class="$style.userSelectButton"
+					@click="selectUser"
+				>
+					<div :class="$style.userSelectButtonInner">
+						<span><i class="ti ti-plus"></i></span>
+						<span>{{ i18n.ts.selectUser }}</span>
+					</div>
+				</MkButton>
+				<div v-else :class="$style.userSelectedButtons">
+					<div style="overflow: hidden;">
+						<MkUserCardMini
+							:user="conditionTestUser"
+							:withChart="false"
+							:class="$style.userSelectedCard"
+						/>
+					</div>
+					<div>
+						<button
+							class="_button"
+							:class="$style.userSelectedSwitchButton"
+							@click="selectUser"
+						>
+							<i class="ph-user-switch ph-bold ph-lg"></i>
+						</button>
+					</div>
+				</div>
+			</div>
 		</div>
 	</MkFolder>
 
@@ -843,10 +875,11 @@ SPDX-License-Identifier: AGPL-3.0-only
 </template>
 
 <script lang="ts" setup>
-import { watch, ref, computed } from 'vue';
+import { watch, ref, computed, shallowRef } from 'vue';
 import { throttle } from 'throttle-debounce';
 import { ROLE_POLICIES } from '@@/js/const.js';
 import RolesEditorFormula from './RolesEditorFormula.vue';
+import type * as Misskey from 'misskey-js';
 import MkInput from '@/components/MkInput.vue';
 import MkColorInput from '@/components/MkColorInput.vue';
 import MkSelect from '@/components/MkSelect.vue';
@@ -854,10 +887,14 @@ import MkTextarea from '@/components/MkTextarea.vue';
 import MkFolder from '@/components/MkFolder.vue';
 import MkSwitch from '@/components/MkSwitch.vue';
 import MkRange from '@/components/MkRange.vue';
+import MkButton from '@/components/MkButton.vue';
+import MkUserCardMini from '@/components/MkUserCardMini.vue';
 import FormSlot from '@/components/form/slot.vue';
 import { i18n } from '@/i18n.js';
 import { instance } from '@/instance.js';
 import { deepClone } from '@/utility/clone.js';
+import * as os from '@/os.js';
+import { misskeyApi } from '@/utility/misskey-api.js';
 
 const emit = defineEmits<{
 	(ev: 'update:modelValue', v: any): void;
@@ -870,6 +907,10 @@ const props = defineProps<{
 
 const role = ref(deepClone(props.modelValue));
 
+const conditionTestUser = shallowRef<Misskey.entities.UserDetailed | null>(null);
+
+const conditionResults = ref(null);
+
 // fill missing policy
 for (const ROLE_POLICY of ROLE_POLICIES) {
 	if (role.value.policies[ROLE_POLICY] == null) {
@@ -908,6 +949,19 @@ function matchQuery(keywords: string[]): boolean {
 	return keywords.some(keyword => keyword.toLowerCase().includes(q.value.toLowerCase()));
 }
 
+async function updateTestResults() {
+	conditionResults.value = await misskeyApi('admin/roles/annotate-condition', { userId: conditionTestUser.value.id, condFormula: role.value.condFormula });
+}
+
+function selectUser() {
+	os.selectUser({
+		includeSelf: true,
+	}).then((_user) => {
+		conditionTestUser.value = _user;
+		updateTestResults();
+	});
+}
+
 const save = throttle(100, () => {
 	const data = {
 		name: role.value.name,
@@ -926,6 +980,10 @@ const save = throttle(100, () => {
 		policies: role.value.policies,
 	};
 
+	if (conditionTestUser.value !== null) {
+		updateTestResults();
+	}
+
 	emit('update:modelValue', data);
 });
 
@@ -940,4 +998,36 @@ watch(role, save, { deep: true });
 .priorityIndicator {
 	margin-left: 8px;
 }
+
+.userSelectLabel {
+	font-size: 0.85em;
+	padding: 0 0 8px;
+	user-select: none;
+}
+
+.userSelectButton {
+	width: 100%;
+	height: 100%;
+	padding: 12px;
+	border: 2px dashed color(from var(--MI_THEME-fg) srgb r g b / 0.5);
+}
+
+.userSelectButtonInner {
+	display: flex;
+	flex-direction: column;
+	align-items: center;
+	justify-content: space-between;
+	min-height: 38px;
+}
+
+.userSelectedButtons {
+	display: grid;
+	grid-template-columns: 1fr auto;
+	align-items: center;
+}
+
+.userSelectedSwitchButton {
+	width: 32px;
+	height: 32px;
+}
 </style>
diff --git a/sharkey-locales/en-US.yml b/sharkey-locales/en-US.yml
index 01ac64bbe5..6bb936217b 100644
--- a/sharkey-locales/en-US.yml
+++ b/sharkey-locales/en-US.yml
@@ -269,6 +269,7 @@ _role:
     remoteFollowingLessThanOrEq: "Follows X or fewer remote accounts"
     remoteFollowingMoreThanOrEq: "Follows X or more remote accounts"
   remoteDataWarning: "This condition may be incorrect for remote users."
+  selectTestUser: "Select a user to test the condition."
 _emailUnavailable:
   banned: "This email address is banned"
 _signup: