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Original: Simon Willison · 17/02/2026

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Summary

Rodney v0.4.0 introduces several new features for the CLI tool, including improved error handling, new commands for testing, and enhanced support for Windows.

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Key Insights

“Errors now use exit code 2, which means exit code 1 is just for check failures.” — Release notes for Rodney v0.4.0
“New rodney assert command for running JavaScript tests, exit code 1 if they fail.” — Feature addition in Rodney v0.4.0
“I’ve been using Showboat to create demos of new features.” — Author’s experience with the tool

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Topics

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Full Article

17th February 2026 Rodney v0.4.0. My Rodney CLI tool for browser automation attracted quite the flurry of PRs since I announced it last week. Here are the release notes for the just-released v0.4.0: Errors now use exit code 2, which means exit code 1 is just for for check failures. #15 New rodney assert command for running JavaScript tests, exit code 1 if they fail. #19 New directory-scoped sessions with —local/—global flags. #14 New reload —hard and clear-cache commands. #17 New rodney start —show option to make the browser window visible. Thanks, Antonio Cuni. #13 New rodney connect PORT command to debug an already-running Chrome instance. Thanks, Peter Fraenkel. #12 New RODNEY_HOME environment variable to support custom state directories. Thanks, Senko Rašić. #11 New —insecure flag to ignore certificate errors. Thanks, Jakub Zgoliński. #10 Windows support: avoid Setsid on Windows via build-tag helpers. Thanks, adm1neca. #18 Tests now run on windows-latest and macos-latest in addition to Linux. I’ve been using Showboat to create demos of new features - here those are for rodney assert, rodney reload —hard, rodney exit codes, and rodney start —local. The rodney assert command is pretty neat: you can now Rodney to test a web app through multiple steps in a shell script that looks something like this (adapted from the README): #!/bin/bash set -euo pipefail FAIL=0 check() { if ! ”@";thenecho"FAIL:@"; then echo "FAIL: *” FAIL=1 fi } rodney start rodney open “https://example.com” rodney waitstable # Assert elements exist check rodney exists “h1” # Assert key elements are visible check rodney visible “h1” check rodney visible “#main-content” # Assert JS expressions check rodney assert ‘document.title’ ‘Example Domain’ check rodney assert ‘document.querySelectorAll(“p”).length’ ‘2’ # Assert accessibility requirements check rodney ax-find —role navigation rodney stop if [ “$FAIL” -ne 0 ]; then echo “Some checks failed” exit 1 fi echo “All checks passed”

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Originally published at https://simonwillison.net/2026/Feb/17/rodney/#atom-everything.