shalomb Kiro Sub-Agent Skill
Launch kiro-cli chat as a headless sub-agent in a tmux pane.
When to use
- Delegating a scoped task to Kiro CLI running autonomously
- Parallel execution alongside other sub-agents (claude, gemini, pi)
- Running Ralph or Bart loops via Kiro instead of Claude CLI
- When you want to use Kiro's tool ecosystem (AWS, code intelligence, etc.)
Key differences from Claude CLI
| Aspect | Claude CLI | Kiro CLI |
|---|---|---|
| Structured output | --output-format stream-json (JSONL) |
None — ANSI terminal output only |
| Non-interactive | --print + --no-session-persistence |
--no-interactive |
| Tool trust | --dangerously-skip-permissions |
-a / --trust-all-tools |
| Prompt input | -p @/path/to/file.md or -p "text" |
Positional argument "text" |
| Model selection | --model haiku|sonnet|opus |
--model <model> |
| Completion signal | {"type":"result"} in JSONL |
Process exit (exit code 0) |
| Cost tracking | total_cost_usd in result event |
Not available in output |
Non-interactive invocation
kiro-cli chat \
--trust-all-tools \
--no-interactive \
--model <model> \
"Your prompt here"
Reading prompt from file
Kiro CLI doesn't support @file syntax. Use command substitution:
kiro-cli chat -a --no-interactive "$(cat /tmp/task-prompt.md)"
Or for very long prompts (argument length limits), use a heredoc wrapper:
cat > /tmp/launch-kiro.sh << 'SCRIPT'
#!/bin/bash
cd /path/to/worktree
kiro-cli chat -a --no-interactive "$(cat /tmp/ralph-task.md)" \
> /tmp/kiro-task.log 2>&1
echo "EXIT_CODE: $?"
SCRIPT
chmod +x /tmp/launch-kiro.sh
Monitoring
Since Kiro doesn't produce JSONL, monitoring is process-based:
Check if still running
# From tmux pane scraping
tmux capture-pane -t "$PANE" -p | tail -5
Check completion
# Look for the credits/time line that signals end of response
tmux capture-pane -t "$PANE" -p | grep -q "Credits:.*Time:" && echo "DONE"
Log-based monitoring
# If output is redirected to a file
tail -f /tmp/kiro-task.log | grep --line-buffered "Credits:"
Launch template (for dispatch.py)
#!/bin/bash
cd {worktree}
kiro-cli chat -a --no-interactive "$(cat {prompt})" \
> {logfile} 2>&1
echo "KIRO_EXIT: $?" >> {logfile}
Completion detection
Unlike Claude's JSONL result event, detect Kiro completion by:
- Process exit — the
kiro-cli chatprocess terminates - Log marker — look for
Credits:andTime:in output - Exit code file — append
echo "KIRO_EXIT: $?"after the command
Limitations
- No structured output — cannot extract cost, turn count, or tool calls programmatically
- No session persistence control beyond
--no-interactive - Prompt size limited by shell argument length (
getconf ARG_MAX, typically 2MB on Linux) - ANSI escape codes in output require stripping for clean log analysis
- No
--append-system-promptequivalent — persona must be included in the prompt text
Integration with agent-mux
In dispatch.py, Kiro uses a different launch template:
AGENT_CONFIG = {
"ralph": {
"runner": "kiro",
"model": None, # uses default
"logfile": "/tmp/kiro-ralph-{id}.log",
},
}
The dispatch script writes the prompt to a file and launches via:
cd <worktree> && kiro-cli chat -a --no-interactive "$(cat <prompt>)" > <logfile> 2>&1