Running Claude Code and Codex side by side on a mobile app? Simlock gives each agent its own simulator
Szymon Chmal introduced Simlock, a free, open-source tool from Callstack Incubator that turns your machine into a self-managing simulator cloud, so each coding agent gets its own iOS or Android device, whether a simulator or a real phone, instead of fighting over the same one. Agents request a lease when they need to test mobile work, several machines can sit behind one API, and it can already be used in T3 Code. Replying to the launch, app developer David Barnard said Codex and Claude Code had created almost 70 simulators (about 300GB, by his recollection) while working on just two apps, so he set up a daily Codex check-in to watch disk space and suggest what to delete.
Why it matters
Parallel agents testing mobile apps can collide on one simulator or quietly fill your disk with dozens of new ones. A lease system and a regular cleanup check keep both under control.
Who it's for
iOS and Android developers running several coding agents, such as Claude Code, Codex or Cursor, at once.
How to try it
- Check how much space your simulators use: on a Mac, run xcrun simctl list devices and look in ~/Library/Developer/CoreSimulator.
- Try Simlock from its GitHub repo so each agent leases its own simulator or device.
- Set a weekly agent task that lists unused simulators and asks you before deleting any.
Plan & availability: Simlock is free and open source on GitHub (callstackincubator/simlock). The project is new, so expect rough edges.
Note: reported by users on X; we haven't independently confirmed it works in the current version.
Source: @ChmalSzymon on X ↗
Written by AgentStackList from the original post. Checked Oct 30, 2026. Features, plans and availability can change, so confirm on the source before you rely on it.
claude-codecodexiosandroidsimulatorsopen-source
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