diff --git a/packages/@d-zero/a11y-check-core/src/scenario-child-process.ts b/packages/@d-zero/a11y-check-core/src/scenario-child-process.ts
index 4aed1c27..81b9d3cc 100644
--- a/packages/@d-zero/a11y-check-core/src/scenario-child-process.ts
+++ b/packages/@d-zero/a11y-check-core/src/scenario-child-process.ts
@@ -1,5 +1,6 @@
 import type { Result, NeedAnalysis, Passed, Scenario } from './types.js';
 
+import { importScenarios, type Violation } from '@d-zero/a11y-check-core';
 import { createChildProcess } from '@d-zero/puppeteer-dealer';
 import {
 	beforePageScan,
@@ -9,8 +10,6 @@ import {
 import { Cache } from '@d-zero/shared/cache';
 import c from 'ansi-colors';
 
-import { importScenarios, type Violation } from '@d-zero/a11y-check-core';
-
 export type ChildProcessParams = {
 	readonly scenarios: readonly Scenario[];
 	readonly cacheDir: string;
diff --git a/packages/@d-zero/a11y-check-core/src/scenario-main-process.ts b/packages/@d-zero/a11y-check-core/src/scenario-main-process.ts
index 46d3f218..a35577b2 100644
--- a/packages/@d-zero/a11y-check-core/src/scenario-main-process.ts
+++ b/packages/@d-zero/a11y-check-core/src/scenario-main-process.ts
@@ -11,13 +11,12 @@ import type { DealOptions } from '@d-zero/dealer';
 
 import path from 'node:path';
 
+import { importScenarios, type Violation } from '@d-zero/a11y-check-core';
 import { createProcess, deal } from '@d-zero/puppeteer-dealer';
 import c from 'ansi-colors';
 
 import { cleanResults } from './clean-results.js';
 
-import { importScenarios, type Violation } from '@d-zero/a11y-check-core';
-
 /**
  *
  * @param urlList
diff --git a/packages/@d-zero/shared/src/path-list-to-tree.spec.ts b/packages/@d-zero/shared/src/path-list-to-tree.spec.ts
index b0141f44..6dec98a6 100644
--- a/packages/@d-zero/shared/src/path-list-to-tree.spec.ts
+++ b/packages/@d-zero/shared/src/path-list-to-tree.spec.ts
@@ -385,6 +385,74 @@ test('Options: currentPath', () => {
 	});
 });
 
+test('Options: currentPath does not false-positive isAncestor on sibling prefix', () => {
+	const result = pathListToTree(
+		['/', '/foo/index.html', '/foo/bar.html', '/foo/bar_baz.html'],
+		{
+			currentPath: '/foo/bar_baz.html',
+		},
+	);
+
+	const foo = result.children[0]!;
+	expect(foo.stem).toBe('/foo/');
+	expect(foo.isAncestor).toBe(true);
+
+	const bar = foo.children.find((c) => c.stem === '/foo/bar')!;
+	expect(bar.isAncestor).toBe(false);
+
+	const barBaz = foo.children.find((c) => c.stem === '/foo/bar_baz')!;
+	expect(barBaz.current).toBe(true);
+});
+
+test('Options: currentPath file is not treated as child of same-prefix directory', () => {
+	const result = pathListToTree(['/', '/foo/', '/foo/bar/', '/foo/bar.html'], {
+		currentPath: '/foo/bar.html',
+	});
+
+	const foo = result.children[0]!;
+	expect(foo.stem).toBe('/foo/');
+	expect(foo.isAncestor).toBe(true);
+
+	const fooBarDir = foo.children.find((c) => c.stem === '/foo/bar/')!;
+	expect(fooBarDir.isAncestor).toBe(false);
+
+	const fooBarFile = foo.children.find((c) => c.stem === '/foo/bar')!;
+	expect(fooBarFile.current).toBe(true);
+});
+
+test('Options: currentPath as root marks root current and no ancestors', () => {
+	const result = pathListToTree(['/', '/a/', '/b.html'], {
+		currentPath: '/',
+	});
+
+	expect(result.current).toBe(true);
+	expect(result.isAncestor).toBe(false);
+	expect(result.children[0]!.isAncestor).toBe(false);
+	expect(result.children[1]!.isAncestor).toBe(false);
+});
+
+test('Options: currentPath deep nesting marks all ancestor directories', () => {
+	const result = pathListToTree(['/', '/a/', '/a/b/', '/a/b/c.html'], {
+		currentPath: '/a/b/c.html',
+	});
+
+	expect(result.isAncestor).toBe(true);
+	expect(result.current).toBe(false);
+
+	const a = result.children[0]!;
+	expect(a.stem).toBe('/a/');
+	expect(a.isAncestor).toBe(true);
+
+	const ab = a.children[0]!;
+	expect(ab.stem).toBe('/a/b/');
+	expect(ab.isAncestor).toBe(true);
+
+	const abc = ab.children[0]!;
+	expect(abc.stem).toBe('/a/b/c');
+	expect(abc.current).toBe(true);
+	expect(abc.isAncestor).toBe(false);
+});
+
 test('Options: addMetaData adds meta to every node', () => {
 	const result = pathListToTree(['/', '/a/', '/a/b', '/a/c/'], {
 		addMetaData: (node) => ({
diff --git a/packages/@d-zero/shared/src/path-list-to-tree.ts b/packages/@d-zero/shared/src/path-list-to-tree.ts
index aac9cfa2..affb48f6 100644
--- a/packages/@d-zero/shared/src/path-list-to-tree.ts
+++ b/packages/@d-zero/shared/src/path-list-to-tree.ts
@@ -51,7 +51,7 @@ export type Node<MetaData = Record<string, unknown>> = {
 	depth: number;
 	/** True if this node is the current path. */
 	current: boolean;
-	/** True if the current path is under this node. */
+	/** True if this node is a directory ancestor of the current path. Only directory nodes (stem ending with '/') can be ancestors. */
 	isAncestor: boolean;
 	/** Present when the node was created as a virtual parent (no real file). */
 	virtual?: true;
@@ -118,7 +118,10 @@ export function pathListToTree<MetaData = Record<string, unknown>>(
 			stem: url.stem,
 			depth: url.depth,
 			current,
-			isAncestor: !current && currentPath ? currentPath.startsWith(url.stem) : false,
+			isAncestor:
+				!current && currentPath
+					? url.stem.endsWith('/') && currentPath.startsWith(url.stem)
+					: false,
 			children: [],
 		});
 	}