Focus Loops

Focus loops enable Claude to work on a task repeatedly until completion, preventing premature exit. When active, Claude’s stop hook intercepts exit attempts and re-injects the task prompt.

Architecture

Claude Code Session
    |
    v
Plugin Stop Hook (claudezilla/plugin/)
    | (Unix socket query)
    v
Claudezilla Host (loop state)
    |
    v
Firefox Extension (visual control)

The plugin hook runs every time Claude tries to end its turn. If a loop is active, it blocks the exit and feeds the prompt back in.

Setup

Link the Claudezilla plugin into your Claude plugins directory:

ln -s /path/to/claudezilla/plugin ~/.claude/plugins/claudezilla-loop

The plugin contains:

• .claude-plugin/ — plugin metadata
• hooks/ — stop hook that queries loop state via Unix socket

Starting a Loop

firefox_start_loop({
  prompt: "Build a REST API with CRUD endpoints for a todo list",
  maxIterations: 20
})

Parameter	Required	Description
prompt	Yes	The task description re-injected each iteration
maxIterations	No	Maximum iterations before auto-stop (default: 10)
completionPromise	No	End loop when <promise>VALUE</promise> is detected

Completion Detection

There are three ways a loop ends:

1. Max Iterations

The loop stops automatically after maxIterations is reached.

2. Manual Stop

firefox_stop_loop()

3. Completion Promise

Set a completion marker that Claude emits when the task is done:

firefox_start_loop({
  prompt: "Fix all TypeScript errors in src/",
  maxIterations: 30,
  completionPromise: "ALL_ERRORS_FIXED"
})

// When Claude determines all errors are fixed, it outputs:
// <promise>ALL_ERRORS_FIXED</promise>
// The hook detects this and stops the loop.

Checking Status

firefox_loop_status()
// {
//   active: true,
//   iteration: 5,
//   maxIterations: 20,
//   prompt: "Build a REST API...",
//   startedAt: "2026-03-06T10:00:00Z"
// }

Browser UI

When a loop is active, the Claudezilla popup shows:

• Current iteration count
• Task prompt preview
• A stop button for manual cancellation

Tips

• Keep prompts specific and actionable. Vague prompts lead to repetitive iterations.
• Set maxIterations as a safety net — most tasks complete well under the limit.
• Use completionPromise for tasks with a clear “done” condition (all tests pass, no errors remain).
• Monitor progress with firefox_loop_status() to see which iteration you’re on.