Every action in your systems used to trace back to a person. AI agents break that link. An agent that signs in with a shared human account leaves you unable to say which agent did what, or whether it should have.
Why it matters
You can't govern what you can't name. A verified identity for each agent is what lets you set limits and prove later who acted. It's the first thing an auditor asks for.
Where teams get it wrong
Teams often hand an agent a human's API key or service account and move on. That works until something breaks. Then the logs point at a person who was asleep, and no one can separate the agent's actions from the human's.
One example
Say a finance bot and a reporting bot both use the same service account. The finance bot moves money it shouldn't. Your logs show the shared account, not which bot ran. Separate identities would have told you in seconds.