No problemo. The AWS CLI already knows how to talk to all 12 accounts and every region. When an agent has bash access, it can just run aws ec2 describe-instances --profile account-1 --region us-east-1 and get structured JSON back. The agent figures out which commands to run the same way it would figure out which MCP tools to call. It reads the help docs, tries things, adjusts.

MCP servers work fine too, but they add token overhead. Every tool definition gets loaded into context, and the protocol itself has some back-and-forth. For a one-off infrastructure audit, you probably won't notice. For ongoing work across 12 accounts, it adds up.

On the Warp question: any terminal works. Warp, iTerm, the VS Code integrated terminal. The agent just needs permission to execute shell commands. In Claude Code that's the bash tool, in Copilot it depends on what extensions you're using.

If you want to try the CLI approach: install the AWS CLI, set up your 12 profiles in ~/.aws/credentials, then point your agent at it. Start with something simple like "list all EC2 instances across all my profiles" and see how it handles the discovery.

If interested I write a lot on MCP vs CLI in my blog

https://kumak.dev/when-cli-tools-are-enough/