Show HN: Awsmux – Multi-account AWS CLI, up to 5.4x faster, 7.4x fewer tokens

Summary

Run one AWS CLI command across your whole fleet in parallel: hundreds of accounts in seconds, safely. One command fanned out across every account and region at once (100 parallel workers by default, --concurrency raises it), identities verified before anything runs, results merged into one stream. No more shell loops that take a coffee break to crawl the fleet. And anything that mutates is stopped by an approval boundary that even an AI agent with your admin credentials cannot talk its way past. The demo above is a real terminal against the bundled 100-account sandbox fleet; replay it yourself in one command with make build fleet-up. And it is measurably cheaper and faster for agents. In a 150-session, three-arm benchmark (identical Claude Opus 4.8 agents, identical prompts, same 100-account fleet), the awsmux arm was cheaper and faster than a raw-shell aws CLI arm in every cell: 1.3x to 2.9x cheaper, 2.3x to 5.4x faster, and up to 7.4x fewer output tokens, at a flat 4 turns whatever the fleet size (the CLI arm matched that only at 10 accounts, then grew to 10.5; cost and output-token differences are all Holm-adjusted p < 0.05). 138 of the 150 sessions passed environment validation, and all 12 exclusions were awsmux's own fault: an MCP startup race under concurrency, so they fell entirely in the MCP-bearing arms. task fleet cost per run (cli vs awsmux) wall time enumerate all VPCs 10 accounts $0.090 vs $0.068 (1.3x) 34s vs 13s enumerate all VPCs 50 accounts $0.239 vs $0.120 (2.0x) 84s vs 23s enumerate all VPCs 100 accounts $0.274 vs $0.193 (1.4x) 94s vs 41s find the world-open group 50 accounts $0.229 vs $0.079 (2.9x) 75s vs 14s find the world-open group 100 accounts $0.152 vs $0.098 (1.5x) 90s vs 17s Full design, statistics, and caveats: docs/BENCHMARK.md. Try it on 100 accounts (none of them real) Prerequisites: Go, Docker, and the aws CLI. make build fleet-up && source .tmp/fleet/env.sh That builds ./bin/awsmux, boots a pinned LocalStack container, and provisions...