refactor: extract _exit_error helper to deduplicate CLI error handling

Six call sites in cli.py repeated the same rprint("[red]...") + raise
typer.Exit(1) pattern. Extracting into _exit_error() reduces each
validation block by one line and makes the intent immediately clear
from the function name.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 2 people

docs/index.md

@@ -78,6 +78,40 @@ Iteration 2 broke a test. Iteration 3 automatically received the failure output
 
 ---
 
+## Why ralph loops?
+
+A single agent conversation fills up its context window, slows down, and eventually loses the plot. Ralph loops solve this by resetting every iteration — the agent always starts fresh.
+
+<div class="grid cards" markdown>
+
+-   :material-refresh:{ .lg .middle } **Fresh context, no decay**
+
+    ---
+
+    Each iteration starts with a clean context window. No conversation bloat, no hallucinated memories, no degradation over time. The agent reads the current state of the codebase every loop.
+
+-   :material-shield-check-outline:{ .lg .middle } **Self-healing feedback**
+
+    ---
+
+    Checks validate the agent's work after each iteration. When something breaks, the failure output feeds into the next iteration automatically — the agent fixes its own mistakes without you stepping in.
+
+-   :material-pencil-outline:{ .lg .middle } **Steer while it runs**
+
+    ---
+
+    The prompt is re-read every iteration. Edit `RALPH.md` while the loop runs and the agent follows your new rules on the next cycle. When it does something dumb, add a sign.
+
+-   :material-git:{ .lg .middle } **Progress lives in git**
+
+    ---
+
+    Every iteration commits to git. If something goes wrong, `git log` shows exactly what happened and `git reset` rolls it back. No opaque internal state to debug or lose.
+
+</div>
+
+---
+
 ## Three primitives
 
 Ralphify extends the basic loop with three building blocks that live in the `.ralphify/` directory:

src/ralphify/cli.py

@@ -37,6 +37,12 @@
 app = typer.Typer()
 
 
+def _exit_error(msg: str) -> None:
+    """Print an error in red and exit with code 1."""
+    rprint(f"[red]{msg}[/red]")
+    raise typer.Exit(1)
+
+
 BANNER_LINES = [
     "██████╗░░█████╗░██╗░░░░░██████╗░██╗░░██╗██╗███████╗██╗░░░██╗",
     "██╔══██╗██╔══██╗██║░░░░░██╔══██╗██║░░██║██║██╔════╝╚██╗░██╔╝",
@@ -99,8 +105,7 @@ def _load_config() -> dict:
     """Load and return the ralph.toml config, exiting if not found."""
     config_path = Path(CONFIG_FILENAME)
     if not config_path.exists():
-        rprint(f"[red]{CONFIG_FILENAME} not found. Run 'ralph init' first.[/red]")
-        raise typer.Exit(1)
+        _exit_error(f"{CONFIG_FILENAME} not found. Run 'ralph init' first.")
     with open(config_path, "rb") as f:
         return tomllib.load(f)
 
@@ -142,14 +147,12 @@ def new(
     try:
         agent_name, agent_path = detect_agent()
     except RuntimeError as e:
-        rprint(f"[red]{e}[/red]")
-        raise typer.Exit(1)
+        _exit_error(str(e))
 
     try:
         install_skill("new-ralph", agent_name)
     except RuntimeError as e:
-        rprint(f"[red]{e}[/red]")
-        raise typer.Exit(1)
+        _exit_error(str(e))
 
     cmd = build_agent_command(agent_name, "new-ralph", name)
     os.execvp(cmd[0], cmd)
@@ -182,16 +185,13 @@ def run(
             toml_ralph=agent.get("ralph", "RALPH.md"),
         )
     except ValueError as e:
-        rprint(f"[red]{e}[/red]")
-        raise typer.Exit(1)
+        _exit_error(str(e))
 
     if not Path(ralph_file_path).exists():
-        rprint(f"[red]Prompt file '{ralph_file_path}' not found.[/red]")
-        raise typer.Exit(1)
+        _exit_error(f"Prompt file '{ralph_file_path}' not found.")
 
     if not shutil.which(command):
-        rprint(f"[red]Agent command '{command}' not found on PATH.[/red]")
-        raise typer.Exit(1)
+        _exit_error(f"Agent command '{command}' not found on PATH.")
 
     if log_dir:
         rprint(f"[dim]Logging output to {log_dir}/[/dim]")