Shared admin credentials work right up until someone resigns or an auditor asks who did what. Here's how to design client AWS account access around cross-account roles, unique external IDs and per-engineer attribution, so twenty accounts need zero shared keys and revocation is one action.
Before I quote AWS work, I run a read-only account health check: six passes covering identity, logging, region sprawl, infrastructure code, cost shape and support escalation. Here are the commands, the pass tests, and the findings that change the number.
Adding another account to a bucket policy takes one line and delegates far more than most people realize. A practical look at AWS cross-account data sharing: the delegation model, the KMS gaps, object ownership, references versus copies, and the guardrails that catch the mistake you will eventually make.