diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7a6ee681..ff64d588 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,11 @@ heading, and (b) bumping `pubspec.yaml` `version:` in the same commit.
 
 ### Added
 
+- Workspace ignore now follows the `ignore_files:` list in `.pql/config.yaml`
+  (ordered, later-wins, per D-4) instead of a hardcoded `.gitignore` +
+  `.clideignore` pair — the single ignore knob clide owns. (T-52)
+- `files.walk` command — a recursive, ignore-pruned, capped flat file listing
+  of the workspace, backing quick-open and search. (T-51, T-52)
 - Sidebar readers (markdown + decision) gain a chrome action bar: back/forward
   history, a single-slot pin (one click sets/replaces; one click to return),
   and an edit pencil that opens the current doc in the editor. (T-189, T-190, T-191)
diff --git a/lib/src/daemon/files_commands.dart b/lib/src/daemon/files_commands.dart
index 6b9dfe8f..c042d9b3 100644
--- a/lib/src/daemon/files_commands.dart
+++ b/lib/src/daemon/files_commands.dart
@@ -7,6 +7,7 @@ import 'dart:io';
 import '../files/ignore.dart';
 import '../files/listing.dart';
 import '../files/path_safety.dart';
+import '../files/pql_config.dart';
 import '../files/watcher.dart';
 import '../ipc/envelope.dart';
 import '../ipc/schema_v1.dart';
@@ -130,6 +131,17 @@ void registerFilesCommands(DaemonDispatcher d, FilesService files) {
     );
   });
 
+  d.register('files.walk', (req) async {
+    final result = await walkFiles(root: files.root, ignore: files.ignore);
+    return IpcResponse.ok(
+      id: req.id,
+      data: {
+        'files': [for (final e in result.files) e.path],
+        'truncated': result.truncated,
+      },
+    );
+  });
+
   d.register('files.watch', (req) async {
     await files.startWatching();
     return IpcResponse.ok(
@@ -153,15 +165,14 @@ Directory _resolveWorkspaceRoot(Directory start) {
   return start.absolute;
 }
 
-/// Build the default IgnoreSet: clide's always-hide list + any
-/// `.gitignore` + `.clideignore` at the workspace root.
-///
-/// D-004 compliance note: this covers the single-file-at-root case.
-/// Full layering across arbitrary paths from `.pql/config.yaml`'s
-/// `ignore_files:` is future work — see Q-024 (to be recorded).
+/// Build the default IgnoreSet: clide's always-hide list layered under
+/// the `ignore_files:` chain from `.pql/config.yaml` (per D-4), in
+/// order, later files winning. clide owns that config key (D-3) and
+/// [readIgnoreFiles] resolves it (defaulting to `.gitignore` —
+/// plus `.clideignore` when present — when the config is absent).
 IgnoreSet _defaultIgnore(Directory root) {
   final contents = <String>[];
-  for (final name in ['.gitignore', '.clideignore']) {
+  for (final name in readIgnoreFiles(root)) {
     final f = File('${root.path}/$name');
     if (f.existsSync()) contents.add(f.readAsStringSync());
   }
diff --git a/lib/src/files/listing.dart b/lib/src/files/listing.dart
index e2a1e757..45d3cb20 100644
--- a/lib/src/files/listing.dart
+++ b/lib/src/files/listing.dart
@@ -73,3 +73,54 @@ Future<List<FileEntry>> listDir({
   });
   return entries;
 }
+
+/// Result of [walkFiles]: the flat file list plus whether the walk
+/// stopped early at [WalkResult.cap].
+class WalkResult {
+  const WalkResult({required this.files, required this.truncated});
+
+  /// Every non-ignored file under the root, repo-relative, sorted by path.
+  final List<FileEntry> files;
+
+  /// True when the [maxFiles] cap was reached and the walk stopped early.
+  final bool truncated;
+}
+
+/// Recursively walk [root], returning every non-ignored *file*
+/// (directories are descended into but not emitted), pruned by
+/// [ignore]. Reuses [listDir] per directory, so ignore filtering,
+/// symlink-escape safety (`followLinks: false`), and per-directory
+/// sorting are inherited.
+///
+/// Capped at [maxFiles] to bound work on pathological trees; when the
+/// cap is hit the walk stops early and [WalkResult.truncated] is set so
+/// callers can surface "results truncated". The returned list is sorted
+/// by repo-relative path for a deterministic contract.
+Future<WalkResult> walkFiles({
+  required Directory root,
+  required IgnoreSet ignore,
+  int maxFiles = 50000,
+}) async {
+  final out = <FileEntry>[];
+  // DFS over repo-relative directory paths; '' is the root itself.
+  final stack = <String>[''];
+  var truncated = false;
+  while (stack.isNotEmpty) {
+    final dir = stack.removeLast();
+    final entries = await listDir(root: root, dir: dir, ignore: ignore);
+    for (final e in entries) {
+      if (e.isDirectory) {
+        stack.add(e.path);
+      } else {
+        out.add(e);
+        if (out.length >= maxFiles) {
+          truncated = true;
+          break;
+        }
+      }
+    }
+    if (truncated) break;
+  }
+  out.sort((a, b) => a.path.compareTo(b.path));
+  return WalkResult(files: out, truncated: truncated);
+}
diff --git a/lib/src/files/pql_config.dart b/lib/src/files/pql_config.dart
new file mode 100644
index 00000000..01748785
--- /dev/null
+++ b/lib/src/files/pql_config.dart
@@ -0,0 +1,54 @@
+/// Reads the clide-owned keys from `.pql/config.yaml`.
+///
+/// Per [D-3] clide owns pql's `ignore_files:` key (and never touches
+/// pql's `.pql/` index/cache data). Per [D-4] that key is the single
+/// knob for ignore layering: an ordered list of gitignore-shaped files
+/// at the workspace root, with later entries winning on per-pattern
+/// conflicts. This module reads the list; the matcher itself lives in
+/// [IgnoreSet] (see `ignore.dart`).
+///
+/// Flutter-free by construction — used by daemon-side file walking and
+/// the search engine, both of which run under `dart test`.
+library;
+
+import 'dart:io';
+
+import 'package:yaml/yaml.dart';
+
+/// The ordered list of ignore-file names to layer when walking the
+/// workspace, read from `ignore_files:` in `.pql/config.yaml`.
+///
+/// Resolution (per D-4):
+///   * config present with an explicit `ignore_files:` list → that list
+///     verbatim. An empty list disables file-based exclusions entirely
+///     (the built-in `.git/` etc. still apply via [IgnoreSet.builtin]).
+///   * config absent / malformed / missing the key → the default
+///     `[.gitignore]`, plus `.clideignore` when that file exists
+///     (clide-specific deviations, per D-4).
+///
+/// Never throws: a missing or unparseable config falls back to the
+/// default, so a broken YAML file can't silently blank the ignore set.
+List<String> readIgnoreFiles(Directory root) {
+  final cfg = File('${root.path}/.pql/config.yaml');
+  if (cfg.existsSync()) {
+    try {
+      final doc = loadYaml(cfg.readAsStringSync());
+      if (doc is YamlMap && doc.containsKey('ignore_files')) {
+        final raw = doc['ignore_files'];
+        if (raw is YamlList) {
+          return [
+            for (final e in raw)
+              if (e is String) e,
+          ];
+        }
+      }
+    } catch (_) {
+      // Malformed YAML — fall through to the default below.
+    }
+  }
+  final names = <String>['.gitignore'];
+  if (File('${root.path}/.clideignore').existsSync()) {
+    names.add('.clideignore');
+  }
+  return names;
+}
diff --git a/test/daemon/files_commands_test.dart b/test/daemon/files_commands_test.dart
index 91cc7cc5..876d17d3 100644
--- a/test/daemon/files_commands_test.dart
+++ b/test/daemon/files_commands_test.dart
@@ -73,6 +73,17 @@ void main() {
     expect(names, ['main.dart']);
   });
 
+  test('files.walk returns a flat, recursive file list (no dirs, no ignored)', () async {
+    final r = await call('files.walk', const {});
+    expect(r.ok, isTrue);
+    final paths = (r.data['files'] as List).cast<String>();
+    expect(paths, containsAll(['README.md', 'pubspec.yaml', 'lib/main.dart']));
+    // Directories themselves are never emitted, and .dart_tool is pruned.
+    expect(paths, isNot(contains('lib')));
+    expect(paths.any((p) => p.startsWith('.dart_tool')), isFalse);
+    expect(r.data['truncated'], isFalse);
+  });
+
   test('files.watch acks subscription', () async {
     final r = await call('files.watch', const {});
     expect(r.ok, isTrue);
diff --git a/test/files/pql_config_test.dart b/test/files/pql_config_test.dart
new file mode 100644
index 00000000..b692723a
--- /dev/null
+++ b/test/files/pql_config_test.dart
@@ -0,0 +1,63 @@
+/// Tests for `readIgnoreFiles` — resolving the clide-owned
+/// `ignore_files:` key from `.pql/config.yaml` (D-3 / D-4).
+library;
+
+import 'dart:io';
+
+import 'package:clide/src/files/pql_config.dart';
+import 'package:test/test.dart';
+
+void main() {
+  late Directory root;
+
+  setUp(() async {
+    root = await Directory.systemTemp.createTemp('clide-pqlconfig-');
+  });
+  tearDown(() async {
+    if (root.existsSync()) root.deleteSync(recursive: true);
+  });
+
+  void writeConfig(String body) {
+    Directory('${root.path}/.pql').createSync();
+    File('${root.path}/.pql/config.yaml').writeAsStringSync(body);
+  }
+
+  test('no config → defaults to [.gitignore]', () {
+    expect(readIgnoreFiles(root), ['.gitignore']);
+  });
+
+  test('no config but .clideignore present → adds it after .gitignore', () {
+    File('${root.path}/.clideignore').writeAsStringSync('build/\n');
+    expect(readIgnoreFiles(root), ['.gitignore', '.clideignore']);
+  });
+
+  test('explicit ignore_files list is honoured verbatim and in order', () {
+    writeConfig('ignore_files: [.gitignore, .pqlignore]\n');
+    expect(readIgnoreFiles(root), ['.gitignore', '.pqlignore']);
+  });
+
+  test('explicit empty list disables file-based exclusions', () {
+    writeConfig('ignore_files: []\n');
+    expect(readIgnoreFiles(root), isEmpty);
+  });
+
+  test('config present but key absent → default (ignores .clideignore rule only via default)', () {
+    writeConfig('frontmatter: yaml\n');
+    expect(readIgnoreFiles(root), ['.gitignore']);
+  });
+
+  test('non-string entries are dropped from the list', () {
+    writeConfig('ignore_files: [.gitignore, 42, .pqlignore]\n');
+    expect(readIgnoreFiles(root), ['.gitignore', '.pqlignore']);
+  });
+
+  test('malformed YAML falls back to the default (never throws)', () {
+    writeConfig('ignore_files: [unterminated\n:::bad');
+    expect(readIgnoreFiles(root), ['.gitignore']);
+  });
+
+  test('ignore_files set to a scalar (not a list) falls back to default', () {
+    writeConfig('ignore_files: .gitignore\n');
+    expect(readIgnoreFiles(root), ['.gitignore']);
+  });
+}
diff --git a/test/files/walk_test.dart b/test/files/walk_test.dart
new file mode 100644
index 00000000..9ea1d150
--- /dev/null
+++ b/test/files/walk_test.dart
@@ -0,0 +1,65 @@
+/// Tests for `walkFiles` — the recursive, ignore-pruned, capped
+/// workspace file walk behind `files.walk` and the search engine.
+library;
+
+import 'dart:io';
+
+import 'package:clide/src/files/ignore.dart';
+import 'package:clide/src/files/listing.dart';
+import 'package:test/test.dart';
+
+void main() {
+  late Directory root;
+
+  setUp(() async {
+    root = await Directory.systemTemp.createTemp('clide-walk-');
+    File('${root.path}/README.md').writeAsStringSync('a');
+    File('${root.path}/pubspec.yaml').writeAsStringSync('b');
+    Directory('${root.path}/lib/src').createSync(recursive: true);
+    File('${root.path}/lib/main.dart').writeAsStringSync('c');
+    File('${root.path}/lib/src/util.dart').writeAsStringSync('d');
+    Directory('${root.path}/build').createSync();
+    File('${root.path}/build/output.bin').writeAsStringSync('e');
+  });
+  tearDown(() async {
+    if (root.existsSync()) root.deleteSync(recursive: true);
+  });
+
+  test('walks recursively, returns files sorted by path', () async {
+    final r = await walkFiles(root: root, ignore: IgnoreSet([]));
+    expect(r.truncated, isFalse);
+    expect(r.files.map((e) => e.path).toList(), [
+      'README.md',
+      'build/output.bin',
+      'lib/main.dart',
+      'lib/src/util.dart',
+      'pubspec.yaml',
+    ]);
+  });
+
+  test('prunes ignored directories (build/ via builtin ignore)', () async {
+    final r = await walkFiles(root: root, ignore: IgnoreSet.builtin());
+    final paths = r.files.map((e) => e.path).toList();
+    expect(paths, isNot(contains('build/output.bin')));
+    expect(paths, containsAll(['README.md', 'lib/main.dart', 'lib/src/util.dart']));
+  });
+
+  test('emits only files, never directory entries', () async {
+    final r = await walkFiles(root: root, ignore: IgnoreSet([]));
+    expect(r.files.every((e) => !e.isDirectory), isTrue);
+  });
+
+  test('respects the maxFiles cap and flags truncation', () async {
+    final r = await walkFiles(root: root, ignore: IgnoreSet([]), maxFiles: 2);
+    expect(r.truncated, isTrue);
+    expect(r.files, hasLength(2));
+  });
+
+  test('an empty workspace yields no files and is not truncated', () async {
+    final empty = await Directory.systemTemp.createTemp('clide-walk-empty-');
+    addTearDown(() => empty.deleteSync(recursive: true));
+    final r = await walkFiles(root: empty, ignore: IgnoreSet([]));
+    expect(r.files, isEmpty);
+    expect(r.truncated, isFalse);
+  });
+}