Fast Facts

1. Stop repeating yourself: Mods run inside Claude Code, enforcing routine checks automatically instead of relying on reminders or slower external hooks.
2. Four practical helpers: The author built mods to mask secrets, flag untested “done” tasks, show plan progress, and monitor context usage.
3. Fast, but not foolproof: A mod check took about 0.27 ms versus 55–99 ms for fresh-process hooks—but mods aren’t security boundaries and can run with your permissions.
4. Automate the right annoyance: Use mods for checks that must happen consistently or update the interface; use instructions for judgment, and stronger security tools for sensitive files.

Claude Code Mods: Custom Hooks to Fix My Biggest AI Coding Frustrations

The reminders that kept coming back

I kept telling Claude Code not to print API keys. Reviewing 60 sessions showed I had repeated that reminder 20 times. I also checked plan files again and again, and saw Claude mark tasks complete before testing recent changes.

Chat instructions helped, but they depended on me remembering to give them. Settings hooks could check tool calls, yet launching a separate process for each check added delay. Claude Code mods offer another option. Introduced in version 2.1.287, mods run inside Claude Code and respond to events as work happens.

Small tools, practical gains

I built four mods around those frustrations. Secret-guard masks some recognized secrets and warns Claude not to reveal them. Done-gate flags task completions when code changed but tests did not run. Plan-meter shows progress on screen, while context-meter tracks context-window use.

The appeal is straightforward: A mod can apply a repeatable check without another model call. In my tests, a simple mod check took about 0.27 milliseconds in the test harness. A check that started a separate process took 55 to 99 milliseconds. However, those figures came from one Windows computer, so results will vary.

Mods also need careful handling. They run with the user’s permissions, and their file operations do not trigger tool permission prompts. Secret-guard can miss unfamiliar or encoded values, so it is not a security boundary. Use access controls or a secrets manager for sensitive files.

Start with one annoyance

Not every habit needs a mod. Use written instructions when Claude must make a judgment. Use a mod when a check needs to happen repeatedly, or when you want live information on screen.

Start small. Review your sessions for repeated reminders, then choose one clear problem. A read-only display, such as plan progress, makes a safer first experiment than a tool that blocks commands. Next, validate the mod, review what it can access and test it in a disposable project.

Mods can reduce friction, but they add executable code to a workflow. That trade-off makes careful testing part of the feature—not an optional extra.

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