It depends on how you're recording the tools as assets, and whether the tool is destroyed, or repaired.

If it's an asset and destroyed, you need to know the original cost + how much depreciation was taken on it. If it's repaired, unless the repair is a full like-new rebuild that greatly extends the life or capability, it's usually expensed.

If it's not an asset, then from an accounting perspective nothing happened, unless you sell it. The expense was recorded in the past.

For tax purposes, generally all Capital Cost that isn't recovered by selling an item continues to be part of the ongoing Capital Cost Allowance, unless the entire cost pool is disposed of. So again, usually, from that perspective nothing has happened.