majiayu000 Skill: Build Variant from Local Kits
Build a complete Bottlerocket variant image using kits published to the local development registry. This enables end-to-end testing of kit changes before publishing to production registries.
Roles
You (reading this file) are the orchestrator.
| Role | Reads | Does |
|---|---|---|
| Orchestrator (you) | SKILL.md, next-step.py output | Runs state machine, spawns subagents, writes outputs |
| State machine | progress.json, workspace files | Decides next action, validates gates |
| Subagent | Phase file (e.g., UPDATE_CONFIG.md) | Executes phase instructions |
⚠️ You do NOT read files in phases/ — pass them to subagents via context_files. Subagents read their phase file and execute it.
Orchestrator Loop
workspace = f"planning/build-variant-{timestamp}"
bash(f"mkdir -p {workspace}")
# Write input configuration
input_data = {
"kits": [
{"name": "bottlerocket-core-kit", "version": "<version>"},
{"name": "bottlerocket-kernel-kit", "version": "<version>"}
],
"variant": "", # Optional: e.g., "aws-k8s-1.31"
"arch": "" # Optional: e.g., "aarch64"
}
write("create", f"{workspace}/input.json", file_text=json.dumps(input_data, indent=2))
while True:
result = bash(f"python3 skills/build-variant-from-local-kits/next-step.py {workspace}",
action = json.loads(result)
if action["type"] == "done":
final = fs_read("Line", f"{workspace}/FINAL.md", 1, 100)
log(final)
break
if action["type"] == "gate_failed":
log(f"Gate failed: {action['reason']}")
break
if action["type"] == "spawn":
r = spawn(
action["prompt"],
context_files=action["context_files"],
context_data=action["context_data"],
allow_tools=True
)
write("create", f"{workspace}/{action['output_file']}", file_text=r.response)
Handling Exceptions
The state machine handles the happy path. When things go wrong, exercise judgment:
| Exception | Response |
|---|---|
| Spawn times out | Assess: retry with longer timeout? Report partial progress? |
| Spawn returns error | Report failure to state machine, let it track retries |
| Empty/invalid response | Treat as failure, report to state machine |
Don't silently advance past failures. Either retry, fail explicitly, or document gaps.
Anti-Patterns
| ❌ Don't | ✅ Do |
|---|---|
| Read phase files yourself | Pass phase files via context_files to subagents |
| Decide what phase is next | State machine decides via next-step.py |
| Skip gates "because it looks done" | Always validate gates |
| Store state in your memory | State lives in progress.json |
| Silently advance past failures | Retry, fail, or document gaps |
Phases
- UPDATE_CONFIG: Update Twoliter.toml and Infra.toml to reference local kits
- UPDATE_LOCK: Run twoliter update to regenerate lock file
- BUILD: Execute cargo make to build the variant
- VALIDATE: Verify the built image exists and is valid
Inputs
The orchestrator must create input.json in the workspace with:
{
"kits": [
{"name": "bottlerocket-core-kit", "version": "1.0.0"},
{"name": "bottlerocket-kernel-kit", "version": "1.0.0"}
],
"variant": "aws-k8s-1.31",
"arch": "x86_64"
}
kits: List of kit names and versions (required)variant: Specific variant to build (optional)arch: Target architecture (optional)
Outputs
FINAL.md: Build summary with image path and next steps
Prerequisites
- Kits already built and published to local registry (use
build-kit-locallyskill) - Local registry running
- Bottlerocket variant repository
When to Use
- Testing kit changes in a complete variant build
- Creating bootable images for local testing
- End-to-end validation of kit modifications