ShellAllowListMiddleware

Validate shell commands against an allow-list without HITL interrupts.

When the agent invokes the execute shell tool, this middleware checks the command against the configured allow-list before execution. Rejected commands are returned as error ToolMessage objects the graph never pauses, so LangSmith traces stay as a single continuous run.

Use this middleware in non-interactive mode to avoid the interrupt/resume cycle that fragments traces.