Staging these two as a head-to-head fight produces a distorted answer.
DeepSeek Harness (dsh on the command line) answers
"how should a harness be built?" It sits on the Cordis plugin system: the kernel handles
mounting, unmounting and dependencies and nothing else, while models, tools, skills,
sessions, sandboxes, storage, loops, scheduling and the UI are all plugins. What it ships
is a minimal kernel you are expected to compose.
Kiro Crew answers "how does a workspace stay alive?" A long-running
Gateway keeps sessions, memory, schedules and task checkpoints across restarts;
corrections settle into lessons, repeated workflows into skills; cron, webhooks,
heartbeats and seven messaging channels sit on top. What it ships is
a workspace that is already assembled and keeps getting better.
Underneath it drives kiro-cli over ACP — which is to say Kiro Crew is itself an
orchestration layer above a harness.
So the matrix below has no winning column and no total score. In most
rows the two sides are not doing the same job better or worse; they are doing different
jobs. The actual decision waits in the last section: do you want composability, or do you
want to skip the assembly?