Lesson 2

.github/copilot-instructions.md

@@ -68,3 +68,31 @@ Do not deviate from this structure when editing or adding chapter content.
 | Devcontainer updated | `.devcontainer/devcontainer.json`, Chapter 00 (setup instructions) |
 | Image or banner changed | `assets/` directory, any README referencing the image |
 | Copilot CLI version requirements change | Chapter 00, Chapter 01, `.devcontainer/devcontainer.json` |
+
+<!-- rtk-instructions v2 -->
+# RTK — Token-Optimized CLI
+
+**rtk** is a CLI proxy that filters and compresses command outputs, saving 60-90% tokens.
+
+## Rule
+
+Always prefix shell commands with `rtk`:
+
+```bash
+# Instead of:              Use:
+git status                 rtk git status
+git log -10                rtk git log -10
+cargo test                 rtk cargo test
+docker ps                  rtk docker ps
+kubectl get pods           rtk kubectl pods
+```
+
+## Meta commands (use directly)
+
+```bash
+rtk gain              # Token savings dashboard
+rtk gain --history    # Per-command savings history
+rtk discover          # Find missed rtk opportunities
+rtk proxy <cmd>       # Run raw (no filtering) but track usage
+```
+<!-- /rtk-instructions -->

.github/hooks/rtk-rewrite.json

@@ -0,0 +1,12 @@
+{
+  "hooks": {
+    "PreToolUse": [
+      {
+        "type": "command",
+        "command": "rtk hook copilot",
+        "cwd": ".",
+        "timeout": 5
+      }
+    ]
+  }
+}

.rtk/filters.toml

@@ -0,0 +1,13 @@
+# Project-local RTK filters — commit this file with your repo.
+# Filters here override user-global and built-in filters.
+# Docs: https://github.com/rtk-ai/rtk#custom-filters
+schema_version = 1
+
+# Example: suppress build noise from a custom tool
+# [filters.my-tool]
+# description = "Compact my-tool output"
+# match_command = "^my-tool\\s+build"
+# strip_ansi = true
+# strip_lines_matching = ["^\\s*$", "^Downloading", "^Installing"]
+# max_lines = 30
+# on_empty = "my-tool: ok"

samples/book-app-project/book_app.py

@@ -1,26 +1,12 @@
 import sys
 from books import BookCollection
+from utils import show_books
 
 
 # Global collection instance
 collection = BookCollection()
 
 
-def show_books(books):
-    """Display books in a user-friendly format."""
-    if not books:
-        print("No books found.")
-        return
-
-    print("\nYour Book Collection:\n")
-
-    for index, book in enumerate(books, start=1):
-        status = "✓" if book.read else " "
-        print(f"{index}. [{status}] {book.title} by {book.author} ({book.year})")
-
-    print()
-
-
 def handle_list():
     books = collection.list_books()
     show_books(books)

samples/book-app-project/utils.py

@@ -8,11 +8,34 @@ def print_menu():
 
 
 def get_user_choice() -> str:
-    return input("Choose an option (1-5): ").strip()
+    while True:
+        choice = input("Choose an option (1-5): ").strip()
+        if choice in {"1", "2", "3", "4", "5"}:
+            return choice
+        print("Invalid choice. Please enter a number between 1 and 5.")
 
 
 def get_book_details():
-    title = input("Enter book title: ").strip()
+    """Prompt the user for book details and return them.
+
+    Prompts (via standard input) for the following fields:
+    - title: required. The function will re-prompt until a non-empty title is provided.
+    - author: optional. An empty string is allowed.
+    - publication year: optional. The function attempts to convert input to int; if conversion
+      fails the year defaults to 0 and a message is printed.
+
+    Returns:
+        tuple[str, str, int]: A 3-tuple of (title, author, year).
+
+    Side effects:
+        - Prints prompts and validation messages to stdout.
+    """
+    while True:
+        title = input("Enter book title: ").strip()
+        if title:
+            break
+        print("Title cannot be empty. Please enter a title.")
+
     author = input("Enter author: ").strip()
 
     year_input = input("Enter publication year: ").strip()
@@ -25,12 +48,15 @@ def get_book_details():
     return title, author, year
 
 
-def print_books(books):
+def show_books(books):
     if not books:
-        print("No books in your collection.")
+        print("No books found.")
         return
 
-    print("\nYour Books:")
+    print("\nYour Book Collection:\n")
+
     for index, book in enumerate(books, start=1):
-        status = "✅ Read" if book.read else "📖 Unread"
-        print(f"{index}. {book.title} by {book.author} ({book.year}) - {status}")
+        status = "✓" if book.read else " "
+        print(f"{index}. [{status}] {book.title} by {book.author} ({book.year})")
+
+    print()