AI systems are becoming increasingly capable of reasoning, planning, using tools, and taking actions. But capability alone is not enough. For systems that may operate inside financial, enterprise, res
aetherxglobal.hashnode.dev7 min read
Kartik N V J K
AI Developer | Making AI reliable, trustworthy & accessible to everyone | Active community contributor
The separation between capability, authority, and verification is the right framing. Most agent frameworks conflate all three: the agent that can run a tool is implicitly authorized to run it, and the tool's response is treated as verified fact. That breaks in production when an agent hallucinates a syntactically valid tool call.
The fail-closed design is harder than it looks. Most frameworks don't have a default deny at the identity level. The agent's context is mutable, and an instruction-injection attack can override the 'only call this tool' rule. The fix is to move the authority boundary from the prompt to the credential: the tool should reject calls that arent cryptographically scoped to a specific session and action. That way, even if the agent's instructions are overridden, the tool still enforces the original policy.
One thing to watch: who grants the authority and how does it survive across agent restarts? If authority is a one-time grant in the agent's context window, it evaporates on token limit reset. A durable session identity that persists authority across runs makes the pattern production-ready.
Separating capability, authority, and verification is the right decomposition, and authority is the one teams under-specify. I apply the same split when I vet MCP servers before trusting them in an agent, checking what a tool is allowed to do separately from what it can do, and wrote it up here: kartiknvjk.hashnode.dev/how-i-evaluate-mcp-server…. Where do you enforce the authority boundary, inside the agent or outside it?