diff --git a/docs/TEST_INTEGRITY.md b/docs/TEST_INTEGRITY.md
index 7659d64..028b5da 100644
--- a/docs/TEST_INTEGRITY.md
+++ b/docs/TEST_INTEGRITY.md
@@ -2541,11 +2541,11 @@ test_integrity_note:
     - id: SCN-dashboard-artifacts
       given: "The dashboard test runs without an artifact environment, with an external runner directory, or with a repository/worktree target"
       when: "It chooses the screenshot output boundary before the browser or screenshot writer starts"
-      then: "The default is a retained fresh external directory with provenance and hashes; explicit external output is honored; repository and symlink-resolved worktree targets fail before protected bytes change"
+      then: "The default is a retained fresh external directory with provenance and hashes; explicit external output is honored; repository, temporary-root, pre-existing and symlink-resolved targets fail before protected bytes change"
   observable_outcomes:
     - "Printed artifact directory, provenance, relative names, byte counts and SHA-256 hashes"
-    - "Refusal code for direct and symlink-resolved tracked-worktree destinations"
-    - "Unchanged tracked baseline bytes after refusal"
+    - "Refusal code for direct, temporary-root, existing-file and symlink-resolved tracked-worktree destinations"
+    - "Unchanged tracked baseline and external user bytes after refusal"
   determinism_controls:
     - "Disposable Git worktrees and temporary directories"
     - "Fixed fixture bytes and SHA-256 assertions; no browser, network, sleep or retry is needed for the boundary scenarios"
diff --git a/scripts/dashboard-artifacts.mjs b/scripts/dashboard-artifacts.mjs
index 0bca6dd..5a9c3e1 100644
--- a/scripts/dashboard-artifacts.mjs
+++ b/scripts/dashboard-artifacts.mjs
@@ -1,12 +1,12 @@
 import { execFileSync } from 'node:child_process';
 import { createHash } from 'node:crypto';
-import { existsSync, mkdtempSync, mkdirSync, readdirSync, readFileSync, realpathSync } from 'node:fs';
+import { existsSync, lstatSync, mkdtempSync, mkdirSync, readdirSync, readFileSync, realpathSync } from 'node:fs';
 import { tmpdir } from 'node:os';
-import { dirname, join, relative, resolve } from 'node:path';
+import { basename, dirname, isAbsolute, join, relative, resolve, sep } from 'node:path';
 
 function isWithin(path, root) {
   const difference = relative(root, path);
-  return difference === '' || (!difference.startsWith('..') && !difference.includes('/../'));
+  return difference === '' || (!isAbsolute(difference) && difference !== '..' && !difference.startsWith(`..${sep}`));
 }
 
 function existingAncestor(path) {
@@ -36,6 +36,28 @@ function refusal(target, protectedRoot) {
   return error;
 }
 
+function targetExists(target) {
+  try {
+    lstatSync(target);
+    return true;
+  } catch (error) {
+    if (error.code === 'ENOENT') return false;
+    throw error;
+  }
+}
+
+function resolvePhysicalDirectory(directory) {
+  const requested = resolve(directory);
+  const ancestor = existingAncestor(requested);
+  return { requested, resolved: resolve(realpathSync(ancestor), relative(ancestor, requested)) };
+}
+
+function assertExternalDirectory({ requested, resolved }, repositoryRoot) {
+  for (const protectedRoot of trackedWorktreeRoots(repositoryRoot)) {
+    if (isWithin(resolved, protectedRoot)) throw refusal(requested, protectedRoot);
+  }
+}
+
 export function createDashboardArtifactDirectory({
   environment = process.env,
   repositoryRoot,
@@ -44,18 +66,33 @@ export function createDashboardArtifactDirectory({
   if (!repositoryRoot) throw new Error('repositoryRoot is required for dashboard artifact isolation');
   const requestedDirectory = environment.TORCH_CHECK_ARTIFACT_DIR;
   if (!requestedDirectory) {
-    const directory = mkdtempSync(join(temporaryRoot, 'torch-dashboard-artifacts-'));
+    const temporary = resolvePhysicalDirectory(temporaryRoot);
+    assertExternalDirectory(temporary, repositoryRoot);
+    const directory = mkdtempSync(join(temporary.resolved, 'torch-dashboard-artifacts-'));
     return { directory, provenance: 'standalone-temporary', requestedDirectory: null };
   }
 
-  const requested = resolve(requestedDirectory);
-  const ancestor = existingAncestor(requested);
-  const resolved = resolve(realpathSync(ancestor), relative(ancestor, requested));
-  for (const protectedRoot of trackedWorktreeRoots(repositoryRoot)) {
-    if (isWithin(resolved, protectedRoot)) throw refusal(requested, protectedRoot);
+  const output = resolvePhysicalDirectory(requestedDirectory);
+  assertExternalDirectory(output, repositoryRoot);
+  mkdirSync(output.resolved, { recursive: true });
+  return { directory: output.resolved, provenance: 'TORCH_CHECK_ARTIFACT_DIR', requestedDirectory: output.requested };
+}
+
+export function prepareDashboardArtifactTargets(artifacts, names) {
+  if (new Set(names).size !== names.length || names.some((name) => name !== basename(name))) {
+    throw new Error('Dashboard screenshot names must be unique plain filenames');
   }
-  mkdirSync(resolved, { recursive: true });
-  return { directory: resolved, provenance: 'TORCH_CHECK_ARTIFACT_DIR', requestedDirectory: requested };
+  const paths = {};
+  for (const name of names) {
+    const target = join(artifacts.directory, name);
+    if (targetExists(target)) {
+      const error = new Error(`DASHBOARD_ARTIFACT_TARGET_EXISTS: refusing to replace ${target}`);
+      error.code = 'DASHBOARD_ARTIFACT_TARGET_EXISTS';
+      throw error;
+    }
+    paths[name] = target;
+  }
+  return Object.freeze(paths);
 }
 
 function artifactFiles(directory, prefix = '') {
diff --git a/scripts/test-dashboard-demo.mjs b/scripts/test-dashboard-demo.mjs
index 63205a5..06b69dd 100644
--- a/scripts/test-dashboard-demo.mjs
+++ b/scripts/test-dashboard-demo.mjs
@@ -1,17 +1,24 @@
 import assert from 'node:assert/strict';
 import { once } from 'node:events';
 import { chromium } from '@playwright/test';
-import { join } from 'node:path';
 import { fileURLToPath } from 'node:url';
 import { createConsoleServer } from '../src/console/server.mjs';
-import { createDashboardArtifactDirectory, describeDashboardArtifacts } from './dashboard-artifacts.mjs';
+import { createDashboardArtifactDirectory, describeDashboardArtifacts, prepareDashboardArtifactTargets } from './dashboard-artifacts.mjs';
 
+const screenshotNames = [
+  'torch-dashboard-operation-outcomes.png', 'torch-dashboard-activity-review.png',
+  'torch-dashboard-check-evidence.png', 'torch-dashboard-owner-briefing-desktop.png',
+  'torch-dashboard-pilot-conclusion.png', 'torch-dashboard-pilot-review.png',
+  'torch-dashboard-manager-wakes.png', 'torch-dashboard-demo-desktop.png',
+  'torch-dashboard-demo-mobile.png', 'torch-dashboard-owner-briefing-mobile.png',
+  'torch-dashboard-live-refresh.png',
+];
 const artifacts = createDashboardArtifactDirectory({
   repositoryRoot: fileURLToPath(new URL('..', import.meta.url)),
 });
-const screenshotDirectory = artifacts.directory;
+const screenshotPaths = prepareDashboardArtifactTargets(artifacts, screenshotNames);
 function screenshotPath(name) {
-  return join(screenshotDirectory, name);
+  return screenshotPaths[name];
 }
 
 const server = createConsoleServer();
diff --git a/test/fleet/dashboard-artifacts.test.mjs b/test/fleet/dashboard-artifacts.test.mjs
index 227ebdc..591d194 100644
--- a/test/fleet/dashboard-artifacts.test.mjs
+++ b/test/fleet/dashboard-artifacts.test.mjs
@@ -4,7 +4,7 @@ import { existsSync, mkdtempSync, mkdirSync, readFileSync, symlinkSync, writeFil
 import { tmpdir } from 'node:os';
 import { join, resolve } from 'node:path';
 import test from 'node:test';
-import { createDashboardArtifactDirectory, describeDashboardArtifacts } from '../../scripts/dashboard-artifacts.mjs';
+import { createDashboardArtifactDirectory, describeDashboardArtifacts, prepareDashboardArtifactTargets } from '../../scripts/dashboard-artifacts.mjs';
 
 function repositoryFixture() {
   const root = mkdtempSync(join(tmpdir(), 'torch-dashboard-artifact-fixture-'));
@@ -24,7 +24,8 @@ test('SCN-dashboard-artifacts: standalone execution retains fresh external scree
   assert.equal(artifacts.provenance, 'standalone-temporary');
   assert.equal(artifacts.requestedDirectory, null);
   assert.equal(artifacts.directory.startsWith(resolve(repositoryRoot)), false);
-  writeFileSync(join(artifacts.directory, 'captured.png'), 'standalone screenshot');
+  const targets = prepareDashboardArtifactTargets(artifacts, ['captured.png']);
+  writeFileSync(targets['captured.png'], 'standalone screenshot');
   assert.deepEqual(describeDashboardArtifacts(artifacts).files, [{
     path: 'captured.png', bytes: 21,
     sha256: '6921ad2c105108a005db4282443624252c392392d85bcb4ca2625c6af488f57c',
@@ -39,20 +40,25 @@ test('SCN-dashboard-artifacts: an explicit external runner directory receives ha
   });
   assert.equal(artifacts.provenance, 'TORCH_CHECK_ARTIFACT_DIR');
   assert.equal(artifacts.directory, resolve(output));
-  writeFileSync(join(artifacts.directory, 'captured.png'), 'runner screenshot');
+  const targets = prepareDashboardArtifactTargets(artifacts, ['captured.png']);
+  writeFileSync(targets['captured.png'], 'runner screenshot');
   assert.deepEqual(describeDashboardArtifacts(artifacts).files, [{
     path: 'captured.png', bytes: 17,
     sha256: '382d6e41938a7a8cc7767e9b519ddbef25e5048fc6fa9fe02faf31bab4148e2b',
   }]);
 });
 
-test('SCN-dashboard-artifacts: repository and symlinked-worktree targets fail before changing preserved baseline bytes', () => {
+test('SCN-dashboard-artifacts: repository, temporary-root, pre-existing and symlink targets fail before changing preserved bytes', () => {
   const repositoryRoot = repositoryFixture();
   const baseline = join(repositoryRoot, 'reports', 'design-system', 'baseline.png');
   const before = readFileSync(baseline);
-  const direct = join(repositoryRoot, 'reports', 'design-system');
+  for (const direct of [join(repositoryRoot, 'reports', 'design-system'), join(repositoryRoot, '..captures')]) {
+    assert.throws(() => createDashboardArtifactDirectory({
+      environment: { TORCH_CHECK_ARTIFACT_DIR: direct }, repositoryRoot,
+    }), (error) => error.code === 'DASHBOARD_ARTIFACT_DIRECTORY_FORBIDDEN');
+  }
   assert.throws(() => createDashboardArtifactDirectory({
-    environment: { TORCH_CHECK_ARTIFACT_DIR: direct }, repositoryRoot,
+    environment: {}, repositoryRoot, temporaryRoot: join(repositoryRoot, 'unsafe-tmp'),
   }), (error) => error.code === 'DASHBOARD_ARTIFACT_DIRECTORY_FORBIDDEN');
   assert.deepEqual(readFileSync(baseline), before);
 
@@ -65,4 +71,22 @@ test('SCN-dashboard-artifacts: repository and symlinked-worktree targets fail be
   }), (error) => error.code === 'DASHBOARD_ARTIFACT_DIRECTORY_FORBIDDEN');
   assert.deepEqual(readFileSync(baseline), before);
   assert.equal(existsSync(join(linkedWorktree, 'reports', 'design-system', 'torch-dashboard-demo-desktop.png')), false);
+
+  const output = mkdtempSync(join(tmpdir(), 'torch-dashboard-existing-output-'));
+  const expected = join(output, 'torch-dashboard-demo-desktop.png');
+  writeFileSync(expected, 'existing user evidence');
+  const external = createDashboardArtifactDirectory({ environment: { TORCH_CHECK_ARTIFACT_DIR: output }, repositoryRoot });
+  assert.throws(() => prepareDashboardArtifactTargets(external, ['torch-dashboard-demo-desktop.png']),
+    (error) => error.code === 'DASHBOARD_ARTIFACT_TARGET_EXISTS');
+  assert.equal(readFileSync(expected, 'utf8'), 'existing user evidence');
+
+  const linkedOutput = mkdtempSync(join(tmpdir(), 'torch-dashboard-linked-output-'));
+  const linkedExpected = join(linkedOutput, 'torch-dashboard-demo-desktop.png');
+  symlinkSync(baseline, linkedExpected);
+  const linkedExternal = createDashboardArtifactDirectory({
+    environment: { TORCH_CHECK_ARTIFACT_DIR: linkedOutput }, repositoryRoot,
+  });
+  assert.throws(() => prepareDashboardArtifactTargets(linkedExternal, ['torch-dashboard-demo-desktop.png']),
+    (error) => error.code === 'DASHBOARD_ARTIFACT_TARGET_EXISTS');
+  assert.deepEqual(readFileSync(baseline), before);
 });