[Bug] PreToolUse hook updatedInput overwritten by subsequent hooks with empty responses

Bug Description
Bug: PreToolUse updatedInput is overwritten when multiple hooks are registered for the same tool

When two PreToolUse hooks are registered for Edit/Write:

• Hook A returns {"permissionDecision": "allow", "updatedInput": {...}}
• Hook B returns nothing (just sys.exit(0))

The updatedInput from Hook A is lost. Hook B's empty response overwrites it.

Example:

• security-guidance (official plugin) has a PreToolUse hook for Edit/Write that returns sys.exit(0) when no security issue is found
• Any custom hook trying to use updatedInput for Edit/Write will be broken when security-guidance is also installed

Expected: updatedInput should be preserved/aggregated across hooks
Actual: Last hook's response overwrites previous hooks' updatedInput

Related: https://github.com/anthropics/claude-code/issues/15897

Environment Info

• Platform: win32
• Terminal: windows-terminal
• Version: 2.0.76
• Feedback ID: 06816c0e-a216-45e9-9cce-655e93c9f76e

Errors

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for information, I tested with and without security-guidance plugin. my plugin works well without.