Ok now show the difference

src-ui/src/app/components/admin/config/config.component.html

@@ -23,17 +23,30 @@
                                     <div class="col">
                                         <div class="card bg-light">
                                             <div class="card-body">
-                                                <div class="card-title d-flex align-items-center">
+                                                <div class="card-title d-flex align-items-center flex-wrap">
                                                     <h6 class="mb-0">
                                                       {{option.title}}
                                                     </h6>
                                                     <a class="btn btn-sm btn-link" title="Read the documentation about this setting" i18n-title [href]="getDocsUrl(option.config_key)" target="_blank" referrerpolicy="no-referrer">
                                                         <i-bs name="info-circle"></i-bs>
                                                     </a>
+                                                    @if (isExternallyConfigured(option.config_key)) {
+                                                      @if (isSet(option.key)) {
+                                                        <span class="badge rounded-pill bg-body-secondary text-dark fw-normal" title="This value overrides {{option.config_key}}, which is set outside Paperless." i18n-title>Overrides external</span>
+                                                      } @else {
+                                                        <span class="badge rounded-pill bg-body-secondary text-dark fw-normal" title="{{option.config_key}} is set outside Paperless. Enter a value here to override it." i18n-title>Set externally</span>
+                                                      }
+                                                    }
                                                     @if (isSet(option.key)) {
-                                                      <button type="button" class="btn btn-sm btn-link text-danger ms-auto pe-0" title="Reset" i18n-title (click)="resetOption(option.key)">
-                                                          <i-bs class="me-1" name="x"></i-bs><ng-container i18n>Reset</ng-container>
-                                                      </button>
+                                                      @if (isExternallyConfigured(option.config_key)) {
+                                                        <button type="button" class="btn btn-sm btn-link text-danger ms-auto pe-0" title="Use the externally configured value" i18n-title (click)="resetOption(option.key)">
+                                                            <i-bs class="me-1" name="x"></i-bs><ng-container i18n>Reset to external</ng-container>
+                                                        </button>
+                                                      } @else {
+                                                        <button type="button" class="btn btn-sm btn-link text-danger ms-auto pe-0" title="Reset" i18n-title (click)="resetOption(option.key)">
+                                                            <i-bs class="me-1" name="x"></i-bs><ng-container i18n>Reset</ng-container>
+                                                        </button>
+                                                      }
                                                     }
                                                 </div>
                                                 <div class="mb-n3">

src-ui/src/app/components/admin/config/config.component.spec.ts

@@ -163,6 +163,19 @@ describe('ConfigComponent', () => {
     expect(component.configForm.get('barcodes_enabled').value).toBeNull()
   })
 
+  it('should identify externally configured options', () => {
+    component.externallyConfiguredVariables = new Set([
+      'PAPERLESS_OCR_LANGUAGE',
+    ])
+
+    expect(
+      component.isExternallyConfigured('PAPERLESS_OCR_LANGUAGE')
+    ).toBeTruthy()
+    expect(
+      component.isExternallyConfigured('PAPERLESS_OCR_OUTPUT_TYPE')
+    ).toBeFalsy()
+  })
+
   it('should group options into sections within a category, or not', () => {
     const sections = component.getCategorySections(ConfigCategory.OCR)
     expect(sections).toEqual([null, ConfigSection.RemoteOCR])

src-ui/src/app/components/admin/config/config.component.ts

@@ -69,6 +69,7 @@ export class ConfigComponent
   public configForm = new FormGroup({})
 
   public errors = {}
+  public externallyConfiguredVariables = new Set<string>()
 
   get optionCategories(): string[] {
     return Object.values(ConfigCategory)
@@ -152,6 +153,9 @@ export class ConfigComponent
   }
 
   private initialize(config: PaperlessConfig) {
+    this.externallyConfiguredVariables = new Set(
+      config.externally_configured_variables ?? []
+    )
     if (!this.store) {
       this.store = new BehaviorSubject(config)
 
@@ -162,7 +166,9 @@ export class ConfigComponent
           this.configForm.patchValue(state, { emitEvent: false })
         })
 
-      this.isDirty$ = dirtyCheck(this.configForm, this.store.asObservable())
+      this.isDirty$ = dirtyCheck(this.configForm, this.store.asObservable(), {
+        excludeKeys: ['externally_configured_variables'],
+      })
     }
     this.configForm.patchValue(config)
 
@@ -227,6 +233,10 @@ export class ConfigComponent
     return this.configForm.get(key).value != null
   }
 
+  public isExternallyConfigured(configKey: string): boolean {
+    return this.externallyConfiguredVariables.has(configKey)
+  }
+
   public resetOption(key: string) {
     this.configForm.get(key).setValue(null)
   }

src-ui/src/app/data/paperless-config.ts

@@ -422,6 +422,7 @@ export const PaperlessConfigOptions: ConfigOption[] = [
 ]
 
 export interface PaperlessConfig extends ObjectWithId {
+  externally_configured_variables: string[]
   output_type: OutputTypeConfig
   pages: number
   language: string

src/documents/tests/test_api_app_config.py

@@ -35,7 +35,8 @@ class TestApiAppConfig(DirectoriesMixin, APITestCase):
         THEN:
             - Existing config
         """
-        response = self.client.get(self.ENDPOINT, format="json")
+        with patch.dict("os.environ", {}, clear=True):
+            response = self.client.get(self.ENDPOINT, format="json")
 
         self.assertEqual(response.status_code, status.HTTP_200_OK)
 
@@ -45,6 +46,7 @@ class TestApiAppConfig(DirectoriesMixin, APITestCase):
             response.data[0],
             {
                 "id": 1,
+                "externally_configured_variables": [],
                 "output_type": None,
                 "pages": None,
                 "language": None,
@@ -91,6 +93,31 @@ class TestApiAppConfig(DirectoriesMixin, APITestCase):
             },
         )
 
+    def test_api_get_config_reports_external_configuration_without_values(self) -> None:
+        with patch.dict(
+            "os.environ",
+            {
+                "PAPERLESS_OCR_LANGUAGE": "eng",
+                "PAPERLESS_REMOTE_OCR_API_KEY": "secret-value",
+                "PAPERLESS_FUTURE_SETTING": "future-value",
+                "UNRELATED_SETTING": "unrelated-value",
+            },
+            clear=True,
+        ):
+            response = self.client.get(self.ENDPOINT, format="json")
+
+        self.assertCountEqual(
+            response.data[0]["externally_configured_variables"],
+            [
+                "PAPERLESS_FUTURE_SETTING",
+                "PAPERLESS_OCR_LANGUAGE",
+                "PAPERLESS_REMOTE_OCR_API_KEY",
+            ],
+        )
+        self.assertNotContains(response, "secret-value")
+        self.assertNotContains(response, "future-value")
+        self.assertNotContains(response, "UNRELATED_SETTING")
+
     def test_api_get_ui_settings_with_config(self) -> None:
         """
         GIVEN:

src/paperless/serialisers.py

@@ -1,4 +1,5 @@
 import logging
+import os
 from io import BytesIO
 
 import magic
@@ -212,6 +213,7 @@ class ProfileSerializer(PasswordValidationMixin, serializers.ModelSerializer[Use
 class ApplicationConfigurationSerializer(
     serializers.ModelSerializer[ApplicationConfiguration],
 ):
+    externally_configured_variables = serializers.SerializerMethodField()
     user_args = serializers.JSONField(binary=True, allow_null=True)
     barcode_tag_mapping = serializers.JSONField(binary=True, allow_null=True)
     llm_api_key = ObfuscatedPasswordField(
@@ -227,6 +229,12 @@ class ApplicationConfigurationSerializer(
 
     OBFUSCATED_FIELDS = ("llm_api_key", "remote_ocr_api_key")
 
+    def get_externally_configured_variables(
+        self,
+        instance: ApplicationConfiguration,
+    ) -> list[str]:
+        return sorted(name for name in os.environ if name.startswith("PAPERLESS_"))
+
     def run_validation(self, data):
         # Empty strings treated as None to avoid unexpected behavior
         if "user_args" in data and data["user_args"] == "":