Agent Self-Evolution and Identity Continuity

When an agent modifies its own prompt, model, or behavior, how does it prove continuity of identity?

AI agents are becoming self-modifying. They update their own prompts, switch models, add capabilities, and change behavior patterns. After enough modifications, is it still the "same" agent?

AIdent's answer: the Ed25519 keypair. As long as the same private key signs the heartbeats, it's the same agent — regardless of how much its internal state has changed.

The agent's public metadata can track its evolution (model versions, prompt changes, capability additions), while the cryptographic identity remains stable. Anyone can verify that today's agent is the same entity that registered months ago.