diff --git a/amethyst/build.gradle.kts b/amethyst/build.gradle.kts
index 1a0a0471c6..a38aa8c62e 100644
--- a/amethyst/build.gradle.kts
+++ b/amethyst/build.gradle.kts
@@ -269,6 +269,21 @@ android {
 
     testOptions {
         unitTests.isReturnDefaultValues = true
+        // Lets TorArtiNativeIntegrationTest's System.loadLibrary("arti_android")
+        // find the desktop-host build of our Arti JNI shim. The Android .so
+        // variants live in src/main/jniLibs/{arm64-v8a,x86_64}/ and are loaded
+        // on-device — this Linux x86_64 .so is just for JVM unit-test runs.
+        // -Pamethyst.arti.integration=true opts the (slow, network-dependent)
+        // tests in; see TorArtiNativeIntegrationTest.kdoc.
+        unitTests.all { test ->
+            test.systemProperty(
+                "java.library.path",
+                "${projectDir}/src/test/native-libs/x86_64-linux",
+            )
+            project
+                .findProperty("amethyst.arti.integration")
+                ?.let { test.systemProperty("amethyst.arti.integration", it.toString()) }
+        }
     }
 }
 
diff --git a/amethyst/src/test/java/com/vitorpamplona/amethyst/ui/tor/TorArtiNativeIntegrationTest.kt b/amethyst/src/test/java/com/vitorpamplona/amethyst/ui/tor/TorArtiNativeIntegrationTest.kt
new file mode 100644
index 0000000000..c16763c826
--- /dev/null
+++ b/amethyst/src/test/java/com/vitorpamplona/amethyst/ui/tor/TorArtiNativeIntegrationTest.kt
@@ -0,0 +1,198 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.ui.tor
+
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Assume.assumeTrue
+import org.junit.Test
+import java.io.File
+import java.net.InetSocketAddress
+import java.net.Proxy
+import java.nio.file.Files
+import java.util.concurrent.TimeUnit
+
+/**
+ * Tier-3 integration tests that drive the real Arti JNI shim on JVM, against the
+ * Linux x86_64 host build of the same wrapper crate that powers Android. The .so
+ * is checked in at `amethyst/src/test/native-libs/x86_64-linux/libarti_android.so`
+ * and the Gradle test task sets `java.library.path` to point at it.
+ *
+ * **Layered safety net for our Tor stack:**
+ *   - [TorManagerTest] — fast unit tests, no Arti, virtual time. Covers Kotlin
+ *     self-heal logic.
+ *   - This file (smoke) — JNI bridge loads, version JNI call works. Always runs
+ *     on Linux x86_64 hosts. ~10ms. Catches build/link regressions in the .so.
+ *   - This file (bootstrap) — opt-in via `-Pamethyst.arti.integration=true`. Hits
+ *     `check.torproject.org` through real Tor. ~30-90s per test. Needs outbound
+ *     TCP egress to arbitrary IPs/ports — works on most dev machines and Docker
+ *     hosts with default networking; *will hang* on CI runners with restrictive
+ *     egress lists.
+ *   - `androidTest/.../tor/TorBootstrapInstrumentedTest` — same shape but against
+ *     the Android .so on a connected device/emulator.
+ *
+ * **Run the slow ones:**
+ * ```
+ * ./gradlew :amethyst:testPlayDebugUnitTest \
+ *     --tests "com.vitorpamplona.amethyst.ui.tor.TorArtiNativeIntegrationTest" \
+ *     -Pamethyst.arti.integration=true
+ * ```
+ */
+class TorArtiNativeIntegrationTest {
+    private var dataDir: File? = null
+
+    @After
+    fun tearDown() {
+        // Drop the in-process client between tests so the state file lock doesn't
+        // bleed across (and our tests stay independent). Idempotent — no-op if
+        // initialize never ran.
+        try {
+            ArtiNative.destroy()
+        } catch (_: Throwable) {
+            // Library may not have loaded if assumeArchAvailable skipped us.
+        }
+        dataDir?.deleteRecursively()
+    }
+
+    /**
+     * Always-on smoke check: the host .so loads via `System.loadLibrary("arti_android")`
+     * (configured by the Gradle test task's `java.library.path`) and a trivial JNI
+     * function returns. If this fails, every other Tor test is moot — typical causes
+     * are a stale .so after an arti version bump, a missing rebuild on the test
+     * native-libs path, or a build that didn't export the expected JNI symbol.
+     */
+    @Test
+    fun `library loads and reports a version`() {
+        assumeArchAvailable()
+        val version = ArtiNative.getVersion()
+        assertTrue("Version string was: $version", version.startsWith("Arti "))
+    }
+
+    /**
+     * Real bootstrap + SOCKS round trip. Regression net for: rustls
+     * `CryptoProvider` install after the v2.3.0 bump, `fs-mistrust` host-trust
+     * override, every Java_..._ArtiNative_* JNI export. Opt-in because it costs
+     * 30-90s and needs network egress that not every CI grants.
+     */
+    @Test(timeout = BOOTSTRAP_TIMEOUT_MS + 60_000L)
+    fun `bootstraps and proxies an HTTPS request through Tor`() {
+        assumeArchAvailable()
+        assumeIntegrationEnabled()
+        dataDir = Files.createTempDirectory("arti-integ-").toFile()
+
+        ArtiNative.setLogCallback { line -> println("[arti] $line") }
+
+        val initResult = ArtiNative.initialize(dataDir!!.absolutePath)
+        assertEquals("initialize returned $initResult", 0, initResult)
+
+        val port = pickPort()
+        val socksResult = ArtiNative.startSocksProxy(port)
+        assertEquals("startSocksProxy returned $socksResult", 0, socksResult)
+
+        val body = fetchThroughSocks(port, "https://check.torproject.org/api/ip")
+        assertTrue(
+            "Response should report IsTor:true — body was: $body",
+            body.contains("\"IsTor\":true"),
+        )
+    }
+
+    /**
+     * Direct regression test for the destroy() / state-file-lock fix landed in
+     * the self-heal work: after destroy, the *same* on-disk data dir must be
+     * re-acquirable by a fresh initialize() — no lock-held error, no need to
+     * clearAllArtiData.
+     */
+    @Test(timeout = (BOOTSTRAP_TIMEOUT_MS * 2) + 60_000L)
+    fun `destroy then re-initialize releases the state file lock cleanly`() {
+        assumeArchAvailable()
+        assumeIntegrationEnabled()
+        dataDir = Files.createTempDirectory("arti-integ-").toFile()
+
+        ArtiNative.setLogCallback { line -> println("[arti] $line") }
+        assertEquals("first initialize", 0, ArtiNative.initialize(dataDir!!.absolutePath))
+        assertEquals("first startSocksProxy", 0, ArtiNative.startSocksProxy(pickPort()))
+
+        assertEquals("destroy returned non-zero", 0, ArtiNative.destroy())
+
+        // Re-init against the same data dir. Must NOT see "state file already locked".
+        assertEquals(
+            "re-initialize after destroy should succeed without clearing data",
+            0,
+            ArtiNative.initialize(dataDir!!.absolutePath),
+        )
+        val secondPort = pickPort()
+        assertEquals("post-destroy startSocksProxy", 0, ArtiNative.startSocksProxy(secondPort))
+
+        val body = fetchThroughSocks(secondPort, "https://check.torproject.org/api/ip")
+        assertTrue("post-re-init IsTor — body was: $body", body.contains("\"IsTor\":true"))
+    }
+
+    private fun fetchThroughSocks(
+        port: Int,
+        url: String,
+    ): String {
+        val client =
+            OkHttpClient
+                .Builder()
+                .proxy(Proxy(Proxy.Type.SOCKS, InetSocketAddress("127.0.0.1", port)))
+                .connectTimeout(60, TimeUnit.SECONDS)
+                .readTimeout(60, TimeUnit.SECONDS)
+                .build()
+        return client.newCall(Request.Builder().url(url).build()).execute().use {
+            assertEquals("HTTP 200 from $url", 200, it.code)
+            it.body.string()
+        }
+    }
+
+    private fun pickPort(): Int = (40_000..49_999).random()
+
+    /**
+     * The checked-in test .so is built for Linux x86_64 only. Skip on other hosts
+     * rather than failing — a developer on macOS or aarch64 shouldn't see a build
+     * break just because they ran the full test suite.
+     */
+    private fun assumeArchAvailable() {
+        val arch = System.getProperty("os.arch")?.lowercase().orEmpty()
+        val os = System.getProperty("os.name")?.lowercase().orEmpty()
+        assumeTrue(
+            "Test .so is provided only for Linux x86_64 (was: $os $arch). " +
+                "To run elsewhere, rebuild with `cargo build --release --target <host>` " +
+                "and place at amethyst/src/test/native-libs/<host>/libarti_android.so.",
+            os.contains("linux") && (arch == "amd64" || arch == "x86_64"),
+        )
+    }
+
+    private fun assumeIntegrationEnabled() {
+        assumeTrue(
+            "Set -Pamethyst.arti.integration=true to enable. Needs network egress " +
+                "to arbitrary IPs/ports (Tor directory authorities + guards) — restrictive " +
+                "CI runners will hang in initialize().",
+            System.getProperty("amethyst.arti.integration") == "true",
+        )
+    }
+
+    companion object {
+        private const val BOOTSTRAP_TIMEOUT_MS: Long = 120_000L
+    }
+}
diff --git a/amethyst/src/test/native-libs/x86_64-linux/libarti_android.so b/amethyst/src/test/native-libs/x86_64-linux/libarti_android.so
new file mode 100755
index 0000000000..ef6d500311
Binary files /dev/null and b/amethyst/src/test/native-libs/x86_64-linux/libarti_android.so differ
diff --git a/tools/arti-build/build-arti-host.sh b/tools/arti-build/build-arti-host.sh
new file mode 100755
index 0000000000..219adeab2d
--- /dev/null
+++ b/tools/arti-build/build-arti-host.sh
@@ -0,0 +1,83 @@
+#!/usr/bin/env bash
+#
+# Build the Arti JNI shim for the *host* (typically Linux x86_64) and stage it
+# under amethyst/src/test/native-libs/<host-tag>/libarti_android.so so the JVM
+# unit tests in TorArtiNativeIntegrationTest can `System.loadLibrary` it.
+#
+# Companion to build-arti.sh, which builds the *Android* targets for shipping
+# in the APK. Same wrapper crate, same lib.rs — only the cargo target differs.
+#
+# Prerequisites:
+#   - Rust toolchain with the host target installed (default after `rustup install stable`).
+#   - The Arti source must already be cloned at .arti-source/ — run build-arti.sh
+#     once first if this is a fresh checkout.
+#
+# Usage:
+#   ./build-arti-host.sh
+#
+# Why this exists:
+#   Tier-3 JVM integration tests in amethyst/src/test/.../tor/TorArtiNativeIntegrationTest
+#   call the real Arti library. The checked-in .so under src/test/native-libs/x86_64-linux/
+#   covers the most common dev/CI host. If you bump ARTI_VERSION or touch
+#   tools/arti-build/src/lib.rs, regenerate the host .so with this script before
+#   running the integration tests; otherwise you'll be testing the previous shim.
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
+WRAPPER_DIR="$SCRIPT_DIR/.arti-source/arti-android-wrapper"
+
+if [ ! -d "$WRAPPER_DIR" ]; then
+    echo "Arti source / wrapper not found at $WRAPPER_DIR."
+    echo "Run ./build-arti.sh first (clones .arti-source and sets up the wrapper)."
+    exit 1
+fi
+
+# Sync the latest wrapper sources into the .arti-source clone — build-arti.sh
+# normally does this, but if you've only edited lib.rs the host build needs it too.
+cp "$SCRIPT_DIR/src/lib.rs" "$WRAPPER_DIR/src/lib.rs"
+
+HOST_TARGET="$(rustc -vV | sed -n 's/^host: //p')"
+case "$HOST_TARGET" in
+    x86_64-unknown-linux-gnu) DEST_TAG="x86_64-linux" ;;
+    aarch64-unknown-linux-gnu) DEST_TAG="aarch64-linux" ;;
+    x86_64-apple-darwin) DEST_TAG="x86_64-macos" ;;
+    aarch64-apple-darwin) DEST_TAG="aarch64-macos" ;;
+    *)
+        echo "Unmapped host target $HOST_TARGET — add it to build-arti-host.sh."
+        exit 1
+        ;;
+esac
+
+OUT_DIR="$PROJECT_ROOT/amethyst/src/test/native-libs/$DEST_TAG"
+mkdir -p "$OUT_DIR"
+
+echo "Building Arti shim for $HOST_TARGET → $OUT_DIR/libarti_android.so"
+cargo build --release \
+    --manifest-path "$WRAPPER_DIR/Cargo.toml" \
+    --target "$HOST_TARGET"
+
+# macOS Rust toolchains produce .dylib, not .so. Rename so the existing
+# System.loadLibrary("arti_android") path keeps working.
+case "$HOST_TARGET" in
+    *-apple-darwin)
+        src="$WRAPPER_DIR/target/$HOST_TARGET/release/libarti_android.dylib"
+        ;;
+    *)
+        src="$WRAPPER_DIR/target/$HOST_TARGET/release/libarti_android.so"
+        ;;
+esac
+
+cp "$src" "$OUT_DIR/libarti_android.so"
+size=$(du -h "$OUT_DIR/libarti_android.so" | cut -f1)
+echo "Built $OUT_DIR/libarti_android.so ($size)"
+echo ""
+echo "Run the smoke test:"
+echo "  ./gradlew :amethyst:testPlayDebugUnitTest \\"
+echo "      --tests com.vitorpamplona.amethyst.ui.tor.TorArtiNativeIntegrationTest"
+echo ""
+echo "Run the full bootstrap tests (needs Tor network egress):"
+echo "  ./gradlew :amethyst:testPlayDebugUnitTest \\"
+echo "      --tests com.vitorpamplona.amethyst.ui.tor.TorArtiNativeIntegrationTest \\"
+echo "      -Pamethyst.arti.integration=true"
diff --git a/tools/arti-build/src/lib.rs b/tools/arti-build/src/lib.rs
index f0a7d05304..81883a31da 100644
--- a/tools/arti-build/src/lib.rs
+++ b/tools/arti-build/src/lib.rs
@@ -170,8 +170,21 @@ pub extern "C" fn Java_com_vitorpamplona_amethyst_ui_tor_ArtiNative_initialize(
     let result: Result<()> = runtime.block_on(async {
         log_info!("Creating Arti client...");
 
-        let config = TorClientConfigBuilder::from_directories(state_dir, cache_dir)
-            .build()?;
+        let mut builder = TorClientConfigBuilder::from_directories(state_dir, cache_dir);
+
+        // Arti's fs-mistrust walks every parent of the state dir and rejects any
+        // that has an "unsafe" owner. On Android the app's private filesDir is
+        // sandboxed by the OS, so the default strict check is correct. On JVM
+        // host runs (TorArtiNativeIntegrationTest) the data dir lives under
+        // /tmp and the check trips on container-style ownership of `/` (UID 999
+        // etc.). Disable it for non-Android targets — these are the test/dev
+        // surface, not a user-facing binary.
+        #[cfg(not(target_os = "android"))]
+        {
+            builder.storage().permissions().dangerously_trust_everyone();
+        }
+
+        let config = builder.build()?;
 
         let client = TorClient::create_bootstrapped(config).await?;