Skill: guytogay/async-command (version 1.2.1)

# async-command **When to use async and how to stop long-running commands.** ## The Core Insight Every long command is an opportunity to do something useful while waiting — or a trap that freezes you out. **Blocking**: You run `make build`, wait 5 minutes, do nothing. **Async**: You start `make build`, it runs in background, you do other things, check back later. Rule of thumb: If a command takes longer than you want to wait, it should run async. ## When to Go Async | Situation | Block or Async? | |-----------|-----------------| | Database migration (30s+) | **Async** | | `pip install` 50 packages | **Async** | | Build a Docker image | **Async** | | `curl` a quick API | Block | | Read a config file | Block | | File search in small dir | Block | | Compiling large project | **Async** | | Running tests | **Async** | | Watching logs | **Async** | ## The Pattern (Universal) ```python # 1. Start in background, yield to not block exec(command="...", yieldMs=30000) # 2. While waiting, do other things # (this is the key benefit - you're not frozen) # 3. When ready, check result process(action="poll", sessionId="<session_id>", timeout=60000) ``` ## The Universal Steps **Step 1: Start without blocking** ```python exec(command="your command here", yieldMs=60000) ``` `yieldMs` = how long to wait before backgrounding. Longer = more output captured. **Step 2: Manage the background job** ```python # Check if done process(action="poll", sessionId="<session_id>", timeout=0) # Wait for completion process(action="poll", sessionId="<session_id>", timeout=60000) # Get partial output process(action="log", sessionId="<session_id>") # Stop it process(action="kill", sessionId="<session_id>") ``` **Step 3: Done.** ## Common Mistakes **Mistake 1**: Blocking a long command with a 5-minute timeout ``` # ❌ What most people do exec(command="make build", timeout=300) # Waits 5 minutes, then fails anyway # ✅ Async approach exec(command="make build", yieldMs=10000) # Starts building, returns immediately, you decide when to check ``` **Mistake 2**: Not using process tool to check results ``` # ❌ Re-running to "check" exec(command="make build", yieldMs=60000) # ...then running it again with exec! # This starts a SECOND build, wastes resources # ✅ Use the process session process(action="poll", sessionId="<session_id>", timeout=120000) ``` **Mistake 3**: Forgetting about background jobs ``` # Start something, then forget about it exec(command="python train_model.py", yieldMs=10000) # (goes on with other work, never checks back) # ✅ Track it, check back periodically exec(command="python train_model.py", yieldMs=10000) # ...later: process(action="poll", sessionId="<session_id>", timeout=60000) ``` ## Emergency Stop: "Stop Now" **Scenario**: You started a long operation, need to abort immediately. **How it works**: 1. Run long commands with `yieldMs` (background mode) — the agent stays responsive 2. Ken says "stop" or runs `nek_stop` 3. Agent kills the background job immediately **Why yieldMs matters**: Commands run in background (yieldMs > 0), agent can respond to messages and process actions even while command is running. Without yieldMs, the agent is blocked and cannot respond. **To stop immediately**: Say "stop", "停止", or any clear stop signal. The agent checks for stop on every heartbeat and before any new command, and will immediately kill all background jobs. **Key rule**: For any command that might need interruption, always use `yieldMs`. The agent stays alive and responsive. ## When NOT to Use - Command is fast (< 5 seconds) - You need the result before proceeding - It's destructive and you want to confirm first ## Mental Model Think of async like a餐厅点菜： 1. 你点了菜（exec → 开始运行） 2. 等着的时候可以做别的事（做其他任务） 3. 好了叫你来取（poll → 检查结果） 4. 可以中途退菜（kill → 停止进程） 不要站在厨房门口等菜做完了才去结账。


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