Creating Hedera Agent Kit Hooks

Hooks are non-blocking extensions that run around the BaseTool lifecycle. They observe and can enrich execution: log calls, write audit trails, track metrics, persist state on Context. They do not block tool execution — that's the job of policies (see agent-kit-policy skill).

Hooks fire only for tools that extend BaseTool. A tool that implements the Tool interface directly without extending BaseTool bypasses the hook system entirely.

When to write a hook vs. a policy

If you want to…	Use
Log/audit/track tool calls	Hook
Enrich `Context` (counters, session state)	Hook
Stop a call from happening when a condition holds	Policy (see `agent-kit-policy`)
Reject specific tool methods	Policy

Built-in hooks include HcsAuditTrailHook and HolAuditTrailHook (HCS-backed audit trails) — both live in @hashgraph/hedera-agent-kit/hooks.

Hedera Hook Creation

Creating Hedera Agent Kit Hooks

When to write a hook vs. a policy

The 7-stage lifecycle