hook-authoringlisted

# Hook Authoring Use hooks for runtime observation and policy decisions at typed lifecycle points. Hooks can observe, allow, or deny; they should not become hidden owners of runtime truth. ## Hook Points Meerkat provides 8 hook points in the agent lifecycle: 1. **RunStarted** — When the agent run begins 2. **PreLlmRequest** — Before sending to the LLM 3. **PostLlmResponse** — After receiving LLM response 4. **PreToolExecution** — Before executing a tool call 5. **PostToolExecution** — After tool execution completes 6. **TurnBoundary** — At the boundary between turns 7. **RunCompleted** — When the agent run completes successfully 8. **RunFailed** — When the agent run fails ## Execution Modes - Foreground blocks execution and can deny. Use for policy enforcement. - Background runs concurrently. Use for logging and analytics. ## Decision Semantics Hooks return one of: - Allow: proceed normally. - Deny: block the operation with a reason. - Observe only: return no decision and no patches. ## Boundaries Semantic hook patches are retired. Hooks can observe typed projections and deny through the typed decision shape; provider parameters, assistant text, tool arguments/results, and final run text remain owned by the runtime/tool/LLM authority that produced them. `failure_policy` is retained for compatibility. Current hook runtime failures fail closed through typed engine errors; they are not converted into warning-only success or hook-local denials by `fail_open` / `fail_clo