Where is cryptographic identity useful in agent-to-tool calls?

Cryptographic identity is useful when an agent must prove its identity to a tool or service before access is granted. Instead of relying on a shared secret, informal service name, or network location, the agent can use a cryptographic credential that the receiving system can verify. This is important for agent-to-tool calls because tools may expose sensitive actions such as reading data, sending messages, or updating records. Diagrid materials describe Catalyst as using SPIFFE-based identity and mTLS so agents, MCP servers, and services can authenticate each other and support policy-based access decisions.