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diff --git a/packages/cli/src/ui/hooks/useSlashCompletion.tsx b/packages/cli/src/ui/hooks/useSlashCompletion.tsx
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+++ b/packages/cli/src/ui/hooks/useSlashCompletion.tsx
@@ -0,0 +1,654 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { useEffect, useCallback, useMemo, useRef } from 'react';
+import * as fs from 'fs/promises';
+import * as path from 'path';
+import { glob } from 'glob';
+import {
+  isNodeError,
+  escapePath,
+  unescapePath,
+  getErrorMessage,
+  Config,
+  FileDiscoveryService,
+  DEFAULT_FILE_FILTERING_OPTIONS,
+} from '@google/gemini-cli-core';
+import { Suggestion } from '../components/SuggestionsDisplay.js';
+import { CommandContext, SlashCommand } from '../commands/types.js';
+import {
+  logicalPosToOffset,
+  TextBuffer,
+} from '../components/shared/text-buffer.js';
+import { isSlashCommand } from '../utils/commandUtils.js';
+import { toCodePoints } from '../utils/textUtils.js';
+import { useCompletion } from './useCompletion.js';
+
+export interface UseSlashCompletionReturn {
+  suggestions: Suggestion[];
+  activeSuggestionIndex: number;
+  visibleStartIndex: number;
+  showSuggestions: boolean;
+  isLoadingSuggestions: boolean;
+  isPerfectMatch: boolean;
+  setActiveSuggestionIndex: React.Dispatch<React.SetStateAction<number>>;
+  setShowSuggestions: React.Dispatch<React.SetStateAction<boolean>>;
+  resetCompletionState: () => void;
+  navigateUp: () => void;
+  navigateDown: () => void;
+  handleAutocomplete: (indexToUse: number) => void;
+}
+
+export function useSlashCompletion(
+  buffer: TextBuffer,
+  dirs: readonly string[],
+  cwd: string,
+  slashCommands: readonly SlashCommand[],
+  commandContext: CommandContext,
+  reverseSearchActive: boolean = false,
+  config?: Config,
+): UseSlashCompletionReturn {
+  const {
+    suggestions,
+    activeSuggestionIndex,
+    visibleStartIndex,
+    showSuggestions,
+    isLoadingSuggestions,
+    isPerfectMatch,
+
+    setSuggestions,
+    setShowSuggestions,
+    setActiveSuggestionIndex,
+    setIsLoadingSuggestions,
+    setIsPerfectMatch,
+    setVisibleStartIndex,
+
+    resetCompletionState,
+    navigateUp,
+    navigateDown,
+  } = useCompletion();
+
+  const completionStart = useRef(-1);
+  const completionEnd = useRef(-1);
+
+  const cursorRow = buffer.cursor[0];
+  const cursorCol = buffer.cursor[1];
+
+  // Check if cursor is after @ or / without unescaped spaces
+  const commandIndex = useMemo(() => {
+    const currentLine = buffer.lines[cursorRow] || '';
+    if (cursorRow === 0 && isSlashCommand(currentLine.trim())) {
+      return currentLine.indexOf('/');
+    }
+
+    // For other completions like '@', we search backwards from the cursor.
+
+    const codePoints = toCodePoints(currentLine);
+    for (let i = cursorCol - 1; i >= 0; i--) {
+      const char = codePoints[i];
+
+      if (char === ' ') {
+        // Check for unescaped spaces.
+        let backslashCount = 0;
+        for (let j = i - 1; j >= 0 && codePoints[j] === '\\'; j--) {
+          backslashCount++;
+        }
+        if (backslashCount % 2 === 0) {
+          return -1; // Inactive on unescaped space.
+        }
+      } else if (char === '@') {
+        // Active if we find an '@' before any unescaped space.
+        return i;
+      }
+    }
+
+    return -1;
+  }, [cursorRow, cursorCol, buffer.lines]);
+
+  useEffect(() => {
+    if (commandIndex === -1 || reverseSearchActive) {
+      resetCompletionState();
+      return;
+    }
+
+    const currentLine = buffer.lines[cursorRow] || '';
+    const codePoints = toCodePoints(currentLine);
+
+    if (codePoints[commandIndex] === '/') {
+      // Always reset perfect match at the beginning of processing.
+      setIsPerfectMatch(false);
+
+      const fullPath = currentLine.substring(commandIndex + 1);
+      const hasTrailingSpace = currentLine.endsWith(' ');
+
+      // Get all non-empty parts of the command.
+      const rawParts = fullPath.split(/\s+/).filter((p) => p);
+
+      let commandPathParts = rawParts;
+      let partial = '';
+
+      // If there's no trailing space, the last part is potentially a partial segment.
+      // We tentatively separate it.
+      if (!hasTrailingSpace && rawParts.length > 0) {
+        partial = rawParts[rawParts.length - 1];
+        commandPathParts = rawParts.slice(0, -1);
+      }
+
+      // Traverse the Command Tree using the tentative completed path
+      let currentLevel: readonly SlashCommand[] | undefined = slashCommands;
+      let leafCommand: SlashCommand | null = null;
+
+      for (const part of commandPathParts) {
+        if (!currentLevel) {
+          leafCommand = null;
+          currentLevel = [];
+          break;
+        }
+        const found: SlashCommand | undefined = currentLevel.find(
+          (cmd) => cmd.name === part || cmd.altNames?.includes(part),
+        );
+        if (found) {
+          leafCommand = found;
+          currentLevel = found.subCommands as
+            | readonly SlashCommand[]
+            | undefined;
+        } else {
+          leafCommand = null;
+          currentLevel = [];
+          break;
+        }
+      }
+
+      let exactMatchAsParent: SlashCommand | undefined;
+      // Handle the Ambiguous Case
+      if (!hasTrailingSpace && currentLevel) {
+        exactMatchAsParent = currentLevel.find(
+          (cmd) =>
+            (cmd.name === partial || cmd.altNames?.includes(partial)) &&
+            cmd.subCommands,
+        );
+
+        if (exactMatchAsParent) {
+          // It's a perfect match for a parent command. Override our initial guess.
+          // Treat it as a completed command path.
+          leafCommand = exactMatchAsParent;
+          currentLevel = exactMatchAsParent.subCommands;
+          partial = ''; // We now want to suggest ALL of its sub-commands.
+        }
+      }
+
+      // Check for perfect, executable match
+      if (!hasTrailingSpace) {
+        if (leafCommand && partial === '' && leafCommand.action) {
+          // Case: /command<enter> - command has action, no sub-commands were suggested
+          setIsPerfectMatch(true);
+        } else if (currentLevel) {
+          // Case: /command subcommand<enter>
+          const perfectMatch = currentLevel.find(
+            (cmd) =>
+              (cmd.name === partial || cmd.altNames?.includes(partial)) &&
+              cmd.action,
+          );
+          if (perfectMatch) {
+            setIsPerfectMatch(true);
+          }
+        }
+      }
+
+      const depth = commandPathParts.length;
+      const isArgumentCompletion =
+        leafCommand?.completion &&
+        (hasTrailingSpace ||
+          (rawParts.length > depth && depth > 0 && partial !== ''));
+
+      // Set completion range
+      if (hasTrailingSpace || exactMatchAsParent) {
+        completionStart.current = currentLine.length;
+        completionEnd.current = currentLine.length;
+      } else if (partial) {
+        if (isArgumentCompletion) {
+          const commandSoFar = `/${commandPathParts.join(' ')}`;
+          const argStartIndex =
+            commandSoFar.length + (commandPathParts.length > 0 ? 1 : 0);
+          completionStart.current = argStartIndex;
+        } else {
+          completionStart.current = currentLine.length - partial.length;
+        }
+        completionEnd.current = currentLine.length;
+      } else {
+        // e.g. /
+        completionStart.current = commandIndex + 1;
+        completionEnd.current = currentLine.length;
+      }
+
+      // Provide Suggestions based on the now-corrected context
+      if (isArgumentCompletion) {
+        const fetchAndSetSuggestions = async () => {
+          setIsLoadingSuggestions(true);
+          const argString = rawParts.slice(depth).join(' ');
+          const results =
+            (await leafCommand!.completion!(commandContext, argString)) || [];
+          const finalSuggestions = results.map((s) => ({ label: s, value: s }));
+          setSuggestions(finalSuggestions);
+          setShowSuggestions(finalSuggestions.length > 0);
+          setActiveSuggestionIndex(finalSuggestions.length > 0 ? 0 : -1);
+          setIsLoadingSuggestions(false);
+        };
+        fetchAndSetSuggestions();
+        return;
+      }
+
+      // Command/Sub-command Completion
+      const commandsToSearch = currentLevel || [];
+      if (commandsToSearch.length > 0) {
+        let potentialSuggestions = commandsToSearch.filter(
+          (cmd) =>
+            cmd.description &&
+            (cmd.name.startsWith(partial) ||
+              cmd.altNames?.some((alt) => alt.startsWith(partial))),
+        );
+
+        // If a user's input is an exact match and it is a leaf command,
+        // enter should submit immediately.
+        if (potentialSuggestions.length > 0 && !hasTrailingSpace) {
+          const perfectMatch = potentialSuggestions.find(
+            (s) => s.name === partial || s.altNames?.includes(partial),
+          );
+          if (perfectMatch && perfectMatch.action) {
+            potentialSuggestions = [];
+          }
+        }
+
+        const finalSuggestions = potentialSuggestions.map((cmd) => ({
+          label: cmd.name,
+          value: cmd.name,
+          description: cmd.description,
+        }));
+
+        setSuggestions(finalSuggestions);
+        setShowSuggestions(finalSuggestions.length > 0);
+        setActiveSuggestionIndex(finalSuggestions.length > 0 ? 0 : -1);
+        setIsLoadingSuggestions(false);
+        return;
+      }
+
+      // If we fall through, no suggestions are available.
+      resetCompletionState();
+      return;
+    }
+
+    // Handle At Command Completion
+    completionEnd.current = codePoints.length;
+    for (let i = cursorCol; i < codePoints.length; i++) {
+      if (codePoints[i] === ' ') {
+        let backslashCount = 0;
+        for (let j = i - 1; j >= 0 && codePoints[j] === '\\'; j--) {
+          backslashCount++;
+        }
+
+        if (backslashCount % 2 === 0) {
+          completionEnd.current = i;
+          break;
+        }
+      }
+    }
+
+    const pathStart = commandIndex + 1;
+    const partialPath = currentLine.substring(pathStart, completionEnd.current);
+    const lastSlashIndex = partialPath.lastIndexOf('/');
+    completionStart.current =
+      lastSlashIndex === -1 ? pathStart : pathStart + lastSlashIndex + 1;
+    const baseDirRelative =
+      lastSlashIndex === -1
+        ? '.'
+        : partialPath.substring(0, lastSlashIndex + 1);
+    const prefix = unescapePath(
+      lastSlashIndex === -1
+        ? partialPath
+        : partialPath.substring(lastSlashIndex + 1),
+    );
+
+    let isMounted = true;
+
+    const findFilesRecursively = async (
+      startDir: string,
+      searchPrefix: string,
+      fileDiscovery: FileDiscoveryService | null,
+      filterOptions: {
+        respectGitIgnore?: boolean;
+        respectGeminiIgnore?: boolean;
+      },
+      currentRelativePath = '',
+      depth = 0,
+      maxDepth = 10, // Limit recursion depth
+      maxResults = 50, // Limit number of results
+    ): Promise<Suggestion[]> => {
+      if (depth > maxDepth) {
+        return [];
+      }
+
+      const lowerSearchPrefix = searchPrefix.toLowerCase();
+      let foundSuggestions: Suggestion[] = [];
+      try {
+        const entries = await fs.readdir(startDir, { withFileTypes: true });
+        for (const entry of entries) {
+          if (foundSuggestions.length >= maxResults) break;
+
+          const entryPathRelative = path.join(currentRelativePath, entry.name);
+          const entryPathFromRoot = path.relative(
+            startDir,
+            path.join(startDir, entry.name),
+          );
+
+          // Conditionally ignore dotfiles
+          if (!searchPrefix.startsWith('.') && entry.name.startsWith('.')) {
+            continue;
+          }
+
+          // Check if this entry should be ignored by filtering options
+          if (
+            fileDiscovery &&
+            fileDiscovery.shouldIgnoreFile(entryPathFromRoot, filterOptions)
+          ) {
+            continue;
+          }
+
+          if (entry.name.toLowerCase().startsWith(lowerSearchPrefix)) {
+            foundSuggestions.push({
+              label: entryPathRelative + (entry.isDirectory() ? '/' : ''),
+              value: escapePath(
+                entryPathRelative + (entry.isDirectory() ? '/' : ''),
+              ),
+            });
+          }
+          if (
+            entry.isDirectory() &&
+            entry.name !== 'node_modules' &&
+            !entry.name.startsWith('.')
+          ) {
+            if (foundSuggestions.length < maxResults) {
+              foundSuggestions = foundSuggestions.concat(
+                await findFilesRecursively(
+                  path.join(startDir, entry.name),
+                  searchPrefix, // Pass original searchPrefix for recursive calls
+                  fileDiscovery,
+                  filterOptions,
+                  entryPathRelative,
+                  depth + 1,
+                  maxDepth,
+                  maxResults - foundSuggestions.length,
+                ),
+              );
+            }
+          }
+        }
+      } catch (_err) {
+        // Ignore errors like permission denied or ENOENT during recursive search
+      }
+      return foundSuggestions.slice(0, maxResults);
+    };
+
+    const findFilesWithGlob = async (
+      searchPrefix: string,
+      fileDiscoveryService: FileDiscoveryService,
+      filterOptions: {
+        respectGitIgnore?: boolean;
+        respectGeminiIgnore?: boolean;
+      },
+      searchDir: string,
+      maxResults = 50,
+    ): Promise<Suggestion[]> => {
+      const globPattern = `**/${searchPrefix}*`;
+      const files = await glob(globPattern, {
+        cwd: searchDir,
+        dot: searchPrefix.startsWith('.'),
+        nocase: true,
+      });
+
+      const suggestions: Suggestion[] = files
+        .filter((file) => {
+          if (fileDiscoveryService) {
+            return !fileDiscoveryService.shouldIgnoreFile(file, filterOptions);
+          }
+          return true;
+        })
+        .map((file: string) => {
+          const absolutePath = path.resolve(searchDir, file);
+          const label = path.relative(cwd, absolutePath);
+          return {
+            label,
+            value: escapePath(label),
+          };
+        })
+        .slice(0, maxResults);
+
+      return suggestions;
+    };
+
+    const fetchSuggestions = async () => {
+      setIsLoadingSuggestions(true);
+      let fetchedSuggestions: Suggestion[] = [];
+
+      const fileDiscoveryService = config ? config.getFileService() : null;
+      const enableRecursiveSearch =
+        config?.getEnableRecursiveFileSearch() ?? true;
+      const filterOptions =
+        config?.getFileFilteringOptions() ?? DEFAULT_FILE_FILTERING_OPTIONS;
+
+      try {
+        // If there's no slash, or it's the root, do a recursive search from workspace directories
+        for (const dir of dirs) {
+          let fetchedSuggestionsPerDir: Suggestion[] = [];
+          if (
+            partialPath.indexOf('/') === -1 &&
+            prefix &&
+            enableRecursiveSearch
+          ) {
+            if (fileDiscoveryService) {
+              fetchedSuggestionsPerDir = await findFilesWithGlob(
+                prefix,
+                fileDiscoveryService,
+                filterOptions,
+                dir,
+              );
+            } else {
+              fetchedSuggestionsPerDir = await findFilesRecursively(
+                dir,
+                prefix,
+                null,
+                filterOptions,
+              );
+            }
+          } else {
+            // Original behavior: list files in the specific directory
+            const lowerPrefix = prefix.toLowerCase();
+            const baseDirAbsolute = path.resolve(dir, baseDirRelative);
+            const entries = await fs.readdir(baseDirAbsolute, {
+              withFileTypes: true,
+            });
+
+            // Filter entries using git-aware filtering
+            const filteredEntries = [];
+            for (const entry of entries) {
+              // Conditionally ignore dotfiles
+              if (!prefix.startsWith('.') && entry.name.startsWith('.')) {
+                continue;
+              }
+              if (!entry.name.toLowerCase().startsWith(lowerPrefix)) continue;
+
+              const relativePath = path.relative(
+                dir,
+                path.join(baseDirAbsolute, entry.name),
+              );
+              if (
+                fileDiscoveryService &&
+                fileDiscoveryService.shouldIgnoreFile(
+                  relativePath,
+                  filterOptions,
+                )
+              ) {
+                continue;
+              }
+
+              filteredEntries.push(entry);
+            }
+
+            fetchedSuggestionsPerDir = filteredEntries.map((entry) => {
+              const absolutePath = path.resolve(baseDirAbsolute, entry.name);
+              const label =
+                cwd === dir ? entry.name : path.relative(cwd, absolutePath);
+              const suggestionLabel = entry.isDirectory() ? label + '/' : label;
+              return {
+                label: suggestionLabel,
+                value: escapePath(suggestionLabel),
+              };
+            });
+          }
+          fetchedSuggestions = [
+            ...fetchedSuggestions,
+            ...fetchedSuggestionsPerDir,
+          ];
+        }
+
+        // Like glob, we always return forwardslashes, even in windows.
+        fetchedSuggestions = fetchedSuggestions.map((suggestion) => ({
+          ...suggestion,
+          label: suggestion.label.replace(/\\/g, '/'),
+          value: suggestion.value.replace(/\\/g, '/'),
+        }));
+
+        // Sort by depth, then directories first, then alphabetically
+        fetchedSuggestions.sort((a, b) => {
+          const depthA = (a.label.match(/\//g) || []).length;
+          const depthB = (b.label.match(/\//g) || []).length;
+
+          if (depthA !== depthB) {
+            return depthA - depthB;
+          }
+
+          const aIsDir = a.label.endsWith('/');
+          const bIsDir = b.label.endsWith('/');
+          if (aIsDir && !bIsDir) return -1;
+          if (!aIsDir && bIsDir) return 1;
+
+          // exclude extension when comparing
+          const filenameA = a.label.substring(
+            0,
+            a.label.length - path.extname(a.label).length,
+          );
+          const filenameB = b.label.substring(
+            0,
+            b.label.length - path.extname(b.label).length,
+          );
+
+          return (
+            filenameA.localeCompare(filenameB) || a.label.localeCompare(b.label)
+          );
+        });
+
+        if (isMounted) {
+          setSuggestions(fetchedSuggestions);
+          setShowSuggestions(fetchedSuggestions.length > 0);
+          setActiveSuggestionIndex(fetchedSuggestions.length > 0 ? 0 : -1);
+          setVisibleStartIndex(0);
+        }
+      } catch (error: unknown) {
+        if (isNodeError(error) && error.code === 'ENOENT') {
+          if (isMounted) {
+            setSuggestions([]);
+            setShowSuggestions(false);
+          }
+        } else {
+          console.error(
+            `Error fetching completion suggestions for ${partialPath}: ${getErrorMessage(error)}`,
+          );
+          if (isMounted) {
+            resetCompletionState();
+          }
+        }
+      }
+      if (isMounted) {
+        setIsLoadingSuggestions(false);
+      }
+    };
+
+    const debounceTimeout = setTimeout(fetchSuggestions, 100);
+
+    return () => {
+      isMounted = false;
+      clearTimeout(debounceTimeout);
+    };
+  }, [
+    buffer.text,
+    cursorRow,
+    cursorCol,
+    buffer.lines,
+    dirs,
+    cwd,
+    commandIndex,
+    resetCompletionState,
+    slashCommands,
+    commandContext,
+    config,
+    reverseSearchActive,
+    setSuggestions,
+    setShowSuggestions,
+    setActiveSuggestionIndex,
+    setIsLoadingSuggestions,
+    setIsPerfectMatch,
+    setVisibleStartIndex,
+  ]);
+
+  const handleAutocomplete = useCallback(
+    (indexToUse: number) => {
+      if (indexToUse < 0 || indexToUse >= suggestions.length) {
+        return;
+      }
+      const suggestion = suggestions[indexToUse].value;
+
+      if (completionStart.current === -1 || completionEnd.current === -1) {
+        return;
+      }
+
+      const isSlash = (buffer.lines[cursorRow] || '')[commandIndex] === '/';
+      let suggestionText = suggestion;
+      if (isSlash) {
+        // If we are inserting (not replacing), and the preceding character is not a space, add one.
+        if (
+          completionStart.current === completionEnd.current &&
+          completionStart.current > commandIndex + 1 &&
+          (buffer.lines[cursorRow] || '')[completionStart.current - 1] !== ' '
+        ) {
+          suggestionText = ' ' + suggestionText;
+        }
+        suggestionText += ' ';
+      }
+
+      buffer.replaceRangeByOffset(
+        logicalPosToOffset(buffer.lines, cursorRow, completionStart.current),
+        logicalPosToOffset(buffer.lines, cursorRow, completionEnd.current),
+        suggestionText,
+      );
+      resetCompletionState();
+    },
+    [cursorRow, resetCompletionState, buffer, suggestions, commandIndex],
+  );
+
+  return {
+    suggestions,
+    activeSuggestionIndex,
+    visibleStartIndex,
+    showSuggestions,
+    isLoadingSuggestions,
+    isPerfectMatch,
+    setActiveSuggestionIndex,
+    setShowSuggestions,
+    resetCompletionState,
+    navigateUp,
+    navigateDown,
+    handleAutocomplete,
+  };
+}