diff --git a/internal/sessions/resolver.go b/internal/sessions/resolver.go
index d08043a..e025fa8 100644
--- a/internal/sessions/resolver.go
+++ b/internal/sessions/resolver.go
@@ -58,15 +58,55 @@ func (r *Resolver) Resolve(source, sessionID string) (*ResolvedSession, error) {
 }
 
 func (r *Resolver) resolveClaude(sessionID string) (*ResolvedSession, error) {
-	claudeProjectPath := claudecode.BuildProjectPath(r.projectPath)
-	baseDir := filepath.Join(r.homeDir, ".claude", "projects", claudeProjectPath)
-	sessionFile := filepath.Join(baseDir, sessionID+".jsonl")
+	path, err := r.findClaudeSessionPath(sessionID)
+	if err != nil {
+		return nil, err
+	}
+	return r.openFileSession(path, SourceClaude, sessionID)
+}
 
-	if !web.IsPathWithinDir(sessionFile, baseDir) {
-		return nil, fmt.Errorf("session not found: %s", sessionID)
+// findClaudeSessionPath locates a Claude session file. When projectPath is set,
+// it looks in the specific project directory. When empty, it searches all project
+// subdirectories under ~/.claude/projects/.
+func (r *Resolver) findClaudeSessionPath(sessionID string) (string, error) {
+	if strings.ContainsAny(sessionID, "/\\") || strings.Contains(sessionID, "..") {
+		return "", fmt.Errorf("session not found: %s", sessionID)
+	}
+
+	projectsRoot := filepath.Join(r.homeDir, ".claude", "projects")
+
+	if r.projectPath != "" {
+		claudeProjectPath := claudecode.BuildProjectPath(r.projectPath)
+		baseDir := filepath.Join(projectsRoot, claudeProjectPath)
+		sessionFile := filepath.Join(baseDir, sessionID+".jsonl")
+		if !web.IsPathWithinDir(sessionFile, baseDir) {
+			return "", fmt.Errorf("session not found: %s", sessionID)
+		}
+		if _, err := os.Stat(sessionFile); err != nil {
+			return "", fmt.Errorf("session not found: %s", sessionID)
+		}
+		return sessionFile, nil
 	}
 
-	return r.openFileSession(sessionFile, SourceClaude, sessionID)
+	// Search all project subdirectories.
+	entries, err := os.ReadDir(projectsRoot)
+	if err != nil {
+		return "", fmt.Errorf("session not found: %s", sessionID)
+	}
+	for _, entry := range entries {
+		if !entry.IsDir() {
+			continue
+		}
+		baseDir := filepath.Join(projectsRoot, entry.Name())
+		sessionFile := filepath.Join(baseDir, sessionID+".jsonl")
+		if _, err := os.Stat(sessionFile); err == nil {
+			if !web.IsPathWithinDir(sessionFile, projectsRoot) {
+				continue
+			}
+			return sessionFile, nil
+		}
+	}
+	return "", fmt.Errorf("session not found: %s", sessionID)
 }
 
 func (r *Resolver) resolveCodex(sessionID string) (*ResolvedSession, error) {
@@ -183,16 +223,7 @@ func (r *Resolver) ResolvePath(source, sessionID string) (string, error) {
 
 	switch source {
 	case SourceClaude:
-		claudeProjectPath := claudecode.BuildProjectPath(r.projectPath)
-		baseDir := filepath.Join(r.homeDir, ".claude", "projects", claudeProjectPath)
-		sessionFile := filepath.Join(baseDir, sessionID+".jsonl")
-		if !web.IsPathWithinDir(sessionFile, baseDir) {
-			return "", fmt.Errorf("session not found: %s", sessionID)
-		}
-		if _, err := os.Stat(sessionFile); err != nil {
-			return "", fmt.Errorf("session not found: %s", sessionID)
-		}
-		return sessionFile, nil
+		return r.findClaudeSessionPath(sessionID)
 	case SourceCodex:
 		path, err := findCodexSession(r.homeDir, sessionID)
 		if err != nil {
diff --git a/internal/sessions/resolver_test.go b/internal/sessions/resolver_test.go
index 175f081..68f07e8 100644
--- a/internal/sessions/resolver_test.go
+++ b/internal/sessions/resolver_test.go
@@ -81,6 +81,55 @@ func TestResolveClaudeSession(t *testing.T) {
 	}
 }
 
+// TestResolveClaudeSessionEmptyProjectPath verifies that when projectPath is
+// empty, the resolver searches all project subdirectories under ~/.claude/projects/
+// to find the session (matching the lister's all-project behaviour).
+func TestResolveClaudeSessionEmptyProjectPath(t *testing.T) {
+	homeDir := t.TempDir()
+
+	sessionID := "session-in-subproject"
+
+	// Create a session file in an arbitrary project subdirectory.
+	projectDir := filepath.Join(homeDir, ".claude", "projects", "some-hashed-project-dir")
+	require.NoError(t, os.MkdirAll(projectDir, 0755))
+
+	entry := map[string]any{"type": "system", "timestamp": "2025-01-15T10:00:00Z", "message": "test"}
+	data, _ := json.Marshal(entry)
+	content := append(data, '\n')
+	require.NoError(t, os.WriteFile(filepath.Join(projectDir, sessionID+".jsonl"), content, 0644))
+
+	// Resolver with empty projectPath should find the session.
+	resolver := newTestResolver("", homeDir)
+
+	resolved, err := resolver.Resolve(SourceClaude, sessionID)
+	require.NoError(t, err)
+	defer func() { _ = resolved.Reader.Close() }()
+
+	assert.Equal(t, SourceClaude, resolved.Metadata.Source)
+	assert.Equal(t, sessionID, resolved.Metadata.ID)
+
+	// ResolvePath should also work.
+	path, err := resolver.ResolvePath(SourceClaude, sessionID)
+	require.NoError(t, err)
+	assert.Contains(t, path, sessionID+".jsonl")
+}
+
+// TestResolveClaudeSessionEmptyProjectPathNotFound verifies that when projectPath
+// is empty and the session doesn't exist in any subdirectory, an error is returned.
+func TestResolveClaudeSessionEmptyProjectPathNotFound(t *testing.T) {
+	homeDir := t.TempDir()
+
+	// Create the projects root with one subdirectory but no matching session.
+	projectDir := filepath.Join(homeDir, ".claude", "projects", "some-project")
+	require.NoError(t, os.MkdirAll(projectDir, 0755))
+	require.NoError(t, os.WriteFile(filepath.Join(projectDir, "other-session.jsonl"), []byte("{}"), 0644))
+
+	resolver := newTestResolver("", homeDir)
+	_, err := resolver.Resolve(SourceClaude, "nonexistent-session")
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "session not found")
+}
+
 func TestResolveUnknownSource(t *testing.T) {
 	resolver := newTestResolver(t.TempDir(), t.TempDir())
 	_, err := resolver.Resolve("unknown-agent", "some-id")