benevolentbandwidth · Bhagat-Atul · Jul 10, 2026 · Jul 10, 2026
diff --git a/.gitignore b/.gitignore
@@ -37,6 +37,20 @@ Thumbs.db
 *.orig
 *.rej
 
+# Python local environments and caches
+__pycache__/
+*.pyc
+*.pyo
+.pytest_cache/
+.ruff_cache/
+.venv/
+venv/
+.env
+
+# Local editor/project scratch
+.vscode/
+tools/
+
 # Project-specific generated reports and caches
 app/.DS_Store
 app/src/.DS_Store

diff --git a/README.md b/README.md
@@ -1,6 +1,6 @@
 # Zest
 
-Zest helps you scan packaged food labels and understand how processed they look. It focuses on the ingredient panel, gives a NOVA-style classification, highlights important ingredients, and keeps your scan history on your device.
+Zest helps you scan packaged food labels and understand how processed they look. It focuses on the ingredient panel, gives a NOVA-style classification, and highlights important ingredients without retaining scan content beyond the active session.
 
 ## Why The Name Zest?
 
@@ -20,10 +20,8 @@ In practice, Zest is about:
 - Show a NOVA-style result for the full label.
 - Break ingredients into compact color-coded bubbles.
 - Show allergen signals in a separate section.
-- Save scan history locally on your phone.
-- Show token and cost usage in scan history, using provider-reported usage when available.
 - Use the same Zest splash, launcher icon, typography, and sound setting across the app.
-- Keep API keys encrypted on device.
+- Use the Zest backend proxy for AI analysis without user AI keys.
 
 ## Feature List
 
@@ -42,26 +40,23 @@ Zest is designed as a consumer-grade ingredient intelligence layer: fast enough
 
 - Images stay on device: captured and uploaded label images are never sent to AI providers.
 - On-device OCR first: ML Kit extracts text locally before any model call happens.
-- Text-only AI analysis: providers receive extracted ingredient text, not the original image.
-- Encrypted key storage: LLM and USDA API keys are stored through encrypted on-device storage.
-- Local-first history: scan results and failed scans are stored locally through Room.
+- Text-only AI analysis: the Zest backend proxy receives extracted ingredient text, not the original image.
+- USDA key storage: USDA barcode lookup keys are stored through encrypted on-device storage when configured.
 - No account required: users can analyze labels without sign-in or cloud sync.
+- Backend abuse controls are a required production hardening item; unauthenticated proxy deployment is only acceptable for testing or limited rollout.
 
 ### Product Intelligence
 
-- Staged AI pipeline: one call for NOVA classification, one call for ingredient cleanup and ultra-processed marker detection, one call for allergens, and chat only on demand.
+- Backend AI pipeline: the app calls the Zest proxy, which runs a backend-owned structured analysis prompt and result chat through Vertex AI.
 - Deterministic model settings: API calls use low-variance parameters for more consistent product behavior.
 - Result-scoped chat: users can ask follow-up questions about the current scan without turning the app into a general chatbot.
 - Barcode support: barcode scans can enrich analysis through USDA data when configured.
-- Failed scan recovery: failed image-based scans can appear in History with a rerun path.
-- Usage visibility: History shows provider-reported token and cost usage by model/provider when available, with local estimates as fallback.
 
 ### Operational Readiness
 
 - Professional Compose UI: shared typography, brand assets, spacing, colors, splash, launcher icon, and sound settings.
 - System back handling: Android back and edge-swipe gestures route within the app instead of accidentally closing it.
 - Build safeguards: source-tree checks block retired demo, legacy, rule-based, and dataless source files before build work proceeds.
-- Release-minded storage: Room migrations preserve history and support failed-scan records.
 - Developer documentation: architecture, pipeline contracts, security, testing, and roadmap docs are maintained under `documentation/`.
 
 ## How To Set It Up
@@ -83,7 +78,6 @@ Zest is designed as a consumer-grade ingredient intelligence layer: fast enough
 3. Review the analysis result.
 4. Review the ingredient capsules to see which corrected ingredients were flagged as ultra-processed markers.
 5. Check the allergen block for separate allergen signals.
-6. Open `History` to revisit old scans.
 
 ## What The Result Means
 
@@ -98,7 +92,7 @@ Ingredient capsules are color-coded from the API-returned ultra-processed marker
 
 Zest is designed to keep your data local by default.
 
-- Scan history stays on your device.
+- Scan images, OCR text, and results exist only for the active session.
 - Saved keys are encrypted on device.
 - Saved keys are not shown back in plain text.
 - No sign-in is required.
@@ -142,12 +136,13 @@ If the app fails to analyze a label:
 
 - Check that the ingredient panel is visible and readable.
 - Try a clearer photo with better lighting.
-- Confirm your API key is saved in `Settings`.
+- Wait a moment and try again if the AI service is temporarily unavailable.
 - For barcode scans, confirm USDA lookup is configured.
 
 ## Project Links
 
 - Repository: https://github.com/benevolentbandwidth/ultraprocessed
 - License: [LICENSE/LICENSE.md](LICENSE/LICENSE.md)
+- Product requirements: [documentation/00-product-requirements.md](documentation/00-product-requirements.md)
 - Technical documentation: [documentation/README.md](documentation/README.md)
 - Non-Android architecture guide: [documentation/00-android-app-guide.md](documentation/00-android-app-guide.md)
diff --git a/app/build.gradle.kts b/app/build.gradle.kts
@@ -5,7 +5,6 @@ plugins {
     id("com.android.application")
     id("org.jetbrains.kotlin.android")
     id("org.jetbrains.kotlin.plugin.compose")
-    id("com.google.devtools.ksp") version "2.3.2"
 }
 
 fun String.asBuildConfigStringLiteral(): String =
@@ -31,6 +30,11 @@ val proxyBaseUrl = localProperties
     .orEmpty()
     .trim()
     .ifBlank { "https://ultraprocessed-ai-proxy-894254677159.us-east1.run.app" }
+val analysisDiagnosticsEnabled = localProperties
+    .getProperty("ZEST_ANALYSIS_DIAGNOSTICS_ENABLED")
+    .orEmpty()
+    .trim()
+    .toBoolean()
 val releaseStoreFile = providers.environmentVariable("ZEST_RELEASE_STORE_FILE").orNull
 val releaseStorePassword = providers.environmentVariable("ZEST_RELEASE_STORE_PASSWORD").orNull
 val releaseKeyAlias = providers.environmentVariable("ZEST_RELEASE_KEY_ALIAS").orNull
@@ -62,6 +66,11 @@ android {
             "PROXY_BASE_URL",
             proxyBaseUrl.asBuildConfigStringLiteral(),
         )
+        buildConfigField(
+            "boolean",
+            "ANALYSIS_DIAGNOSTICS_ENABLED",
+            analysisDiagnosticsEnabled.toString(),
+        )
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
         vectorDrawables {
@@ -196,10 +205,45 @@ val verifyNoDatalessSources = tasks.register("verifyNoDatalessSources") {
     }
 }
 
+val verifySessionOnlyStorage = tasks.register("verifySessionOnlyStorage") {
+    group = "verification"
+    description = "Fails if archived Room/history code or active persistence wiring returns."
+    doLast {
+        val sourceRoot = layout.projectDirectory.dir("src/main").asFile
+        val forbidden = listOf(
+            "NovaDatabase",
+            "ScanResultDao",
+            "androidx.room",
+            "HistoryScreen",
+            "AppDestination.History",
+            "insertScanResult",
+            "getAllScanResults",
+        )
+        val violations = sourceRoot.walkTopDown()
+            .filter {
+                it.isFile &&
+                    (it.extension == "kt" || it.extension == "xml") &&
+                    !it.relativeTo(sourceRoot).path.startsWith("archive/")
+            }
+            .flatMap { file ->
+                val contents = file.readText()
+                forbidden.filter { token -> contents.contains(token) }.map { token ->
+                    "${file.relativeTo(projectDir)} contains $token"
+                }
+            }
+            .toList()
+        if (violations.isNotEmpty()) {
+            throw GradleException(
+                "Session-only storage policy violation:\n" + violations.joinToString("\n")
+            )
+        }
+    }
+}
+
 val verifySourceTreeForBuild = tasks.register("verifySourceTreeForBuild") {
     group = "verification"
     description = "Guards the Android source tree from retired files and macOS dataless placeholders."
-    dependsOn(verifyNoRetiredSourceFiles, verifyNoDatalessSources)
+    dependsOn(verifyNoRetiredSourceFiles, verifyNoDatalessSources, verifySessionOnlyStorage)
 }
 
 tasks.named("preBuild") {
@@ -214,14 +258,8 @@ tasks.matching {
     dependsOn(verifyReleaseSigning)
 }
 
-ksp {
-    arg("room.incremental", "true")
-    arg("room.schemaLocation", "$projectDir/schemas")
-}
-
 dependencies {
     val composeBom = platform("androidx.compose:compose-bom:2024.09.00")
-    val roomVersion = "2.8.4"
 
     implementation(composeBom)
     androidTestImplementation(composeBom)
@@ -253,14 +291,9 @@ dependencies {
     androidTestImplementation("androidx.test:core:1.6.1")
     androidTestImplementation("androidx.test.ext:junit:1.2.1")
     androidTestImplementation("androidx.test.espresso:espresso-core:3.6.1")
-    androidTestImplementation("androidx.room:room-testing:$roomVersion")
 
     debugImplementation("androidx.compose.ui:ui-tooling")
     debugImplementation("androidx.compose.ui:ui-test-manifest")
-    // Room
-    implementation("androidx.room:room-runtime:$roomVersion")
-    implementation("androidx.room:room-ktx:$roomVersion")
-    ksp("androidx.room:room-compiler:$roomVersion")
 // Coroutines
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.7.3")
 // Security Crypto (Keystore)

diff --git a/app/src/androidTest/java/com/b2/ultraprocessed/ui/AppChromeFunctionalTest.kt b/app/src/androidTest/java/com/b2/ultraprocessed/ui/AppChromeFunctionalTest.kt
@@ -24,7 +24,6 @@ class AppChromeFunctionalTest {
 
     @Test
     fun scannerScreen_rendersSharedHeaderAndFooter_andRoutesHeaderActions() {
-        var historyClicks = 0
         var settingsClicks = 0
         var barcodeClicks = 0
 
@@ -36,20 +35,17 @@ class AppChromeFunctionalTest {
                     onScan = {},
                     onBarcodeScanned = { barcodeClicks += 1 },
                     onSettings = { settingsClicks += 1 },
-                    onHistory = { historyClicks += 1 },
                 )
             }
         }
 
         composeRule.onNodeWithTag(AppTestTags.HEADER).assertIsDisplayed()
         composeRule.onNodeWithTag(AppTestTags.FOOTER).assertIsDisplayed()
         composeRule.onNodeWithText("Zest").assertIsDisplayed()
-        composeRule.onNodeWithTag(AppTestTags.HEADER_ACTION_HISTORY).performClick()
         composeRule.onNodeWithTag(AppTestTags.HEADER_ACTION_SETTINGS).performClick()
         composeRule.onNodeWithTag(AppTestTags.SCANNER_BARCODE_BUTTON).performClick()
 
         composeRule.runOnIdle {
-            assertEquals(1, historyClicks)
             assertEquals(1, settingsClicks)
             assertEquals(1, barcodeClicks)
         }
@@ -62,9 +58,8 @@ class AppChromeFunctionalTest {
                 ResultsScreen(
                     result = sampleScanResult,
                     onScanAgain = {},
-                    onOpenHistory = {},
                     chatEnabled = false,
-                    onAskAboutResult = { _, _ ->
+                    onAskAboutResult = { _, _, _ ->
                         Result.failure(IllegalStateException("Chat is disabled in this test."))
                     },
                 )
@@ -84,9 +79,8 @@ class AppChromeFunctionalTest {
                 ResultsScreen(
                     result = sampleScanResult.copy(novaGroup = 3),
                     onScanAgain = {},
-                    onOpenHistory = {},
                     chatEnabled = false,
-                    onAskAboutResult = { _, _ ->
+                    onAskAboutResult = { _, _, _ ->
                         Result.failure(IllegalStateException("Chat is disabled in this test."))
                     },
                 )
@@ -108,10 +102,9 @@ class AppChromeFunctionalTest {
                 ResultsScreen(
                     result = sampleScanResult,
                     onScanAgain = {},
-                    onOpenHistory = {},
                     chatEnabled = true,
                     onSoundEffect = { sounds += it },
-                    onAskAboutResult = { _, _ ->
+                    onAskAboutResult = { _, _, _ ->
                         Result.success(
                             ResultChatReply(
                                 allowed = true,

diff --git a/app/src/main/java/com/b2/ultraprocessed/analysis/AnalysisDebugLogger.kt b/app/src/main/java/com/b2/ultraprocessed/analysis/AnalysisDebugLogger.kt
@@ -1,43 +1,16 @@
 package com.b2.ultraprocessed.analysis
 
 import android.content.Context
-import android.util.Log
-import java.io.File
-import java.text.SimpleDateFormat
-import java.util.Date
-import java.util.Locale
-
+/**
+ * Retained as a source-compatible no-op while diagnostics are archived.
+ * Human OCR/model data must never be written to Logcat or an app file.
+ */
 object AnalysisDebugLogger {
-    private const val TAG = "ZestAnalysisTrace"
-    private const val MAX_LOG_BYTES = 512_000L
-    private val lock = Any()
-
-    @Volatile
-    private var logFile: File? = null
-
     fun initialize(context: Context) {
-        val directory = File(context.filesDir, "zest-debug").apply { mkdirs() }
-        logFile = File(directory, "analysis_trace.log")
-        AnalysisTelemetry.sink = { line -> log("telemetry", line) }
-        log("logger", "initialized path=${logFile?.absolutePath.orEmpty()}")
+        AnalysisTelemetry.sink = null
     }
 
-    fun log(stage: String, message: String) {
-        val line = "${timestamp()} [$stage] ${message.take(8_000)}"
-        runCatching { Log.d(TAG, line) }
-        val file = logFile
-        if (file == null) {
-            println(line)
-            return
-        }
-        synchronized(lock) {
-            if (file.length() > MAX_LOG_BYTES) {
-                file.writeText("")
-            }
-            file.appendText(line + "\n")
-        }
-    }
+    fun log(stage: String, message: String) = Unit
 
-    private fun timestamp(): String =
-        SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS", Locale.US).format(Date())
+    fun clear(context: Context) = Unit
 }
diff --git a/app/src/main/java/com/b2/ultraprocessed/analysis/AnalysisTelemetry.kt b/app/src/main/java/com/b2/ultraprocessed/analysis/AnalysisTelemetry.kt
@@ -23,6 +23,6 @@ object AnalysisTelemetry {
 
     private fun log(message: String) {
         val formatted = "ZestAnalysis $message"
-        sink?.invoke(formatted) ?: println(formatted)
+        sink?.invoke(formatted)
     }
 }