Devops Hand Skill

DevOps Expert Knowledge

CI/CD Pipeline Patterns

GitHub Actions Reference

Basic workflow structure:

name: CI/CD Pipeline
on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Build
        run: make build
      - name: Test
        run: make test
      - name: Lint
        run: make lint

  deploy:
    needs: build
    if: github.ref == 'refs/heads/main'
    runs-on: ubuntu-latest
    steps:
      - name: Deploy
        run: make deploy

Useful API endpoints:

# List workflow runs
curl -s -H "Authorization: Bearer $GITHUB_TOKEN" \
  "https://api.github.com/repos/OWNER/REPO/actions/runs?per_page=10"

# Get workflow run details
curl -s -H "Authorization: Bearer $GITHUB_TOKEN" \
  "https://api.github.com/repos/OWNER/REPO/actions/runs/RUN_ID"

# Re-run failed jobs
curl -s -X POST -H "Authorization: Bearer $GITHUB_TOKEN" \
  "https://api.github.com/repos/OWNER/REPO/actions/runs/RUN_ID/rerun-failed-jobs"

Pipeline Optimization Checklist

• Cache dependencies (node_modules, .cargo, pip cache)
• Parallelize independent jobs
• Use matrix builds for multi-version testing
• Skip unnecessary steps on non-code changes
• Use shallow clones for faster checkout
• Optimize Docker layer caching
• Run expensive tests only on main branch

Infrastructure Monitoring

Health Check Patterns

HTTP endpoint check:

curl -s -o /dev/null -w "%{http_code} %{time_total}s" --max-time 10 "$URL"

TCP port check:

nc -z -w5 hostname port && echo "UP" || echo "DOWN"

SSL certificate expiry:

echo | openssl s_client -servername HOST -connect HOST:443 2>/dev/null | \
  openssl x509 -noout -dates

DNS resolution:

dig +short hostname

Disk usage:

df -h | grep -v tmpfs

Memory usage:

free -h

The Four Golden Signals

Docker Monitoring Commands

# Container status
docker ps --format "table {{.Names}}\t{{.Status}}\t{{.Ports}}"

# Resource usage
docker stats --no-stream --format "table {{.Name}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.NetIO}}"

# Container logs (last 100 lines)
docker logs --tail 100 CONTAINER_NAME

# Inspect container health
docker inspect --format='{{.State.Health.Status}}' CONTAINER_NAME

Kubernetes Monitoring Commands

# Pod status across all namespaces
kubectl get pods --all-namespaces -o wide

# Resource usage
kubectl top pods --all-namespaces
kubectl top nodes

# Recent events (errors and warnings)
kubectl get events --sort-by=.lastTimestamp --field-selector type!=Normal

# Pod logs
kubectl logs POD_NAME -n NAMESPACE --tail=100

# Describe failing pod
kubectl describe pod POD_NAME -n NAMESPACE

Deployment Strategies

Blue-Green Deployment

1. Run current version on "Blue" environment
2. Deploy new version to "Green" environment
3. Run health checks on Green
4. Switch traffic from Blue to Green
5. Keep Blue as rollback target
6. After validation period, decommission Blue

Canary Deployment

1. Deploy new version to small subset (5-10% of traffic)
2. Monitor error rates and latency
3. If healthy, gradually increase traffic (25% -> 50% -> 100%)
4. If problems detected, route all traffic back to old version

Rolling Update

1. Update instances one at a time
2. Wait for health check to pass before updating next
3. If any instance fails health check, pause and alert
4. Continue until all instances updated

Deployment Checklist

• All tests passing in CI
• Database migrations compatible (backward and forward)
• Feature flags configured for new features
• Monitoring and alerting in place
• Rollback procedure documented and tested
• On-call engineer notified
• Change request approved (if required)

Incident Response

Incident Lifecycle

Detection -> Triage -> Mitigation -> Investigation -> Resolution -> Post-mortem

Severity Levels

Incident Response Template

# Incident Report: [Title]
**Severity**: SEV[1-4]
**Status**: [Investigating | Mitigated | Resolved]
**Duration**: [Start time] - [End time]

## Timeline
- HH:MM - [Event or action taken]
- HH:MM - [Event or action taken]

## Root Cause
[What caused the incident]

## Impact
[Who was affected and how]

## Mitigation
[What was done to restore service]

## Resolution
[What was done to fix the root cause]

## Action Items
- [ ] [Preventive measure 1]
- [ ] [Preventive measure 2]

## Lessons Learned
[What we can improve]

Infrastructure as Code

Terraform Quick Reference

# Initialize
terraform init

# Plan changes
terraform plan -out=tfplan

# Apply changes
terraform apply tfplan

# Show current state
terraform show

# Destroy resources (DANGEROUS)
terraform destroy

Docker Compose Quick Reference

# Start services
docker compose up -d

# Stop services
docker compose down

# View logs
docker compose logs -f SERVICE_NAME

# Rebuild and restart
docker compose up -d --build SERVICE_NAME

# Scale a service
docker compose up -d --scale SERVICE_NAME=3

Common Failure Diagnosis Playbooks

Memory Leak Detection

# Track memory growth over time
while true; do
  ps aux --sort=-%mem | head -5 | awk '{print strftime("%H:%M:%S"), $2, $4"%", $11}'
  sleep 60
done

# Check for OOM kills
dmesg | grep -i "oom\|killed" | tail -20

# Kubernetes memory pressure
kubectl top pods --sort-by=memory | head -10

DNS Failure Cascade

# Test DNS resolution
dig hostname +short
dig @8.8.8.8 hostname +short  # Bypass local DNS

# Check /etc/resolv.conf
cat /etc/resolv.conf

# Test from inside a container
kubectl exec -it POD -- nslookup hostname

Database Connection Pool Exhaustion

# Check active connections (PostgreSQL)
psql -c "SELECT count(*) FROM pg_stat_activity WHERE state = 'active';"
psql -c "SELECT max_conn FROM pg_settings WHERE name = 'max_connections';"

# Check for long-running queries
psql -c "SELECT pid, now() - pg_stat_activity.query_start AS duration, query
         FROM pg_stat_activity WHERE state != 'idle' ORDER BY duration DESC LIMIT 10;"

Certificate Expiry Monitoring

# Check cert expiry for a list of domains
for domain in api.example.com app.example.com; do
  expiry=$(echo | openssl s_client -servername $domain -connect $domain:443 2>/dev/null | \
    openssl x509 -noout -enddate 2>/dev/null | cut -d= -f2)
  echo "$domain: $expiry"
done

Worked Examples

Example 1: Zero-Downtime Deployment Pipeline

Full lifecycle from code merge to production traffic switch with rollback safety.

Phases: CI build and push image -> deploy to Green -> health-gate -> traffic switch -> monitor -> done (or rollback).

Traffic switch script (the critical step):

#!/bin/bash
set -euo pipefail
# Record current slot for rollback, then switch
CURRENT=$(kubectl get svc myapp-active -n production -o jsonpath='{.spec.selector.slot}')
echo "$CURRENT" > /tmp/rollback-slot
kubectl patch svc myapp-active -n production -p '{"spec":{"selector":{"slot":"green"}}}'
# Verify
sleep 5 && curl -sf https://api.example.com/api/health | jq '.version'

Rollback: read /tmp/rollback-slot, patch the service selector back, verify health.

Decision flowchart:

Code merged to main
  |
  v
CI build + test ----[FAIL]----> Block merge, notify author
  |
  [PASS]
  v
Deploy to Green
  |
  v
Health checks ------[FAIL]----> Alert on-call, keep Blue active
  |
  [PASS]
  v
Switch traffic to Green
  |
  v
Monitor 15 min -----[ERROR SPIKE]----> Rollback to Blue, open incident
  |
  [STABLE]
  v
Mark Green as new Blue, done

Example 2: Production Incident Response

Walkthrough of a real-world SEV1 incident: API latency spike caused by a database connection pool exhaustion.

Timeline

Detection -- Alerting rules that fired

# Prometheus alerting rule
groups:
  - name: api-latency
    rules:
      - alert: HighAPILatency
        expr: histogram_quantile(0.95, rate(http_request_duration_seconds_bucket{job="api"}[5m])) > 2
        for: 2m
        labels:
          severity: critical
        annotations:
          summary: "P95 latency above 2s for 2+ minutes"
          runbook: "https://wiki.internal/runbooks/high-latency"

Triage -- Quick diagnosis commands

# 1. Check if it's a specific endpoint or global
curl -s "http://prometheus:9090/api/v1/query?query=topk(5,rate(http_request_duration_seconds_sum[5m])/rate(http_request_duration_seconds_count[5m]))" | jq '.data.result[] | {endpoint: .metric.handler, avg_latency: .value[1]}'

# 2. Check database connection pool
psql -c "SELECT count(*) as total, state FROM pg_stat_activity GROUP BY state;"

# 3. Find the blocking query
psql -c "SELECT pid, now() - query_start AS duration, query
         FROM pg_stat_activity
         WHERE state = 'active' AND now() - query_start > interval '1 minute'
         ORDER BY duration DESC LIMIT 5;"

Mitigation -- Kill the offending query

# Kill the long-running query by PID
psql -c "SELECT pg_terminate_backend(12345);"

# Verify pool is recovering
watch -n 2 'psql -t -c "SELECT count(*) FROM pg_stat_activity WHERE state = '''active''';"'

Prevention -- Fix applied after incident

-- Set statement timeout for analytics role
ALTER ROLE analytics_readonly SET statement_timeout = '300s';

# Add connection pool monitoring alert
- alert: DBConnectionPoolNearCapacity
  expr: pg_stat_activity_count / pg_settings_max_connections > 0.8
  for: 1m
  labels:
    severity: warning
  annotations:
    summary: "DB connection pool above 80% capacity"

Post-mortem action items:

• Add statement_timeout to all non-interactive database roles
• Add connection pool utilization alerts (threshold: 80%)
• Move analytics queries to read replica
• Add circuit breaker to API when pool utilization exceeds 90%

Example 3: Infrastructure Scaling Event

Scaling a Kubernetes deployment in response to sustained load increase.

Phase 1 -- Alert triggers

Alert: HighCPUUtilization
  Condition: avg(cpu_usage) > 80% for 10 minutes
  Current:   87% across 3 pods
  Namespace: production
  Deployment: order-service

Phase 2 -- Capacity analysis

kubectl top pods -l app=order-service -n production   # Per-pod CPU/memory
kubectl describe nodes | grep -A 5 "Allocated resources"  # Node headroom
kubectl get hpa order-service -n production            # Current HPA state
# Result: 87% CPU across 3 pods, 842 req/s (2x baseline)

Phase 3 -- Scaling decision matrix

Phase 4 -- Implement scaling

# Option A: Manual scale (immediate)
kubectl scale deployment order-service -n production --replicas=6

# Option B: Adjust HPA for sustained load (preferred)
kubectl patch hpa order-service -n production \
  -p '{"spec":{"minReplicas":5,"maxReplicas":15}}'

# Monitor rollout
kubectl rollout status deployment/order-service -n production

# Watch pods come up
kubectl get pods -l app=order-service -n production -w

Phase 5 -- Verify scaling

Confirm via kubectl top pods (CPU should drop to ~45% per pod), check P95 latency is back below SLO, and verify error rate < 1%.

Post-scaling actions:

• Investigate root cause of traffic increase (marketing event? bot traffic? organic growth?)
• Update capacity planning spreadsheet
• If sustained, adjust resource requests/limits and HPA baselines
• Set calendar reminder to review and potentially scale down in 48h

Observability Deep Dive

Structured Logging

Use consistent JSON log format across all services for machine-parseable aggregation.

Log format standard: JSON with required fields: timestamp, level, service, trace_id, span_id, request_id, message. Add error and context (structured key-value) as needed.

Log levels -- when to use each:

Correlation IDs: generate X-Request-ID at API gateway, propagate through all downstream calls. Query across services by filtering on request_id.keyword in Elasticsearch/OpenSearch.

Distributed Tracing

Core concepts: A Trace is the end-to-end request path. Each service call is a Span with timing. Spans nest to show the call tree (e.g., API Gateway -> Order Service -> DB Query + Payment Service -> Stripe API).

OpenTelemetry propagation: traceparent: 00-<trace-id>-<span-id>-<flags>, tracestate: vendor=value.

Useful trace queries (Jaeger/Tempo):

curl -s "http://jaeger:16686/api/traces?service=order-service&minDuration=1s&limit=20"  # Slow traces
curl -s "http://jaeger:16686/api/traces?service=order-service&tags=error%3Dtrue&limit=20"  # Error traces

Alerting Best Practices

Avoid alert fatigue -- rules of thumb:

• Every alert must have a runbook link
• Every alert must be actionable (if no one needs to act, it is a log, not an alert)
• Group related alerts to avoid notification storms
• Use inhibition rules: if the cluster is down, suppress per-pod alerts

SLO-based alerting (burn rate):

# SLO: 99.9% availability = 43.2 min/month error budget
# Fast burn (exhausts budget in 2h): error_ratio > 14.4 * 0.001 for 2m -> critical
# Slow burn (exhausts budget in 3d): error_ratio > 3 * 0.001 for 15m -> warning
groups:
  - name: slo-burn-rate
    rules:
      - alert: SLOBurnRateCritical
        expr: sum(rate(http_requests_total{code=~"5.."}[5m])) / sum(rate(http_requests_total[5m])) > (14.4 * 0.001)
        for: 2m
        labels: { severity: critical }
      - alert: SLOBurnRateWarning
        expr: sum(rate(http_requests_total{code=~"5.."}[1h])) / sum(rate(http_requests_total[1h])) > (3 * 0.001)
        for: 15m
        labels: { severity: warning }

Runbook template: Each alert runbook should cover: what the alert means (one sentence), impact scope, diagnosis steps (dashboard + commands), mitigation (quick fix vs proper fix), and escalation path (who to contact after 15 min).

Metrics Collection Patterns

RED Method (request-scoped services):

USE Method (infrastructure resources):

When to use which:

• RED for services that handle requests (APIs, web servers, message consumers)
• USE for infrastructure (CPU, memory, disk, network interfaces, queues)
• Combine both for a complete picture

Security Operations

Secret Management

Principles:

• Never store secrets in source code, environment variables (in Dockerfiles), or container images
• Use a secrets manager (Vault, AWS Secrets Manager, K8s Secrets with encryption at rest)
• Rotate secrets on a schedule and immediately after any suspected compromise
• Audit all secret access

Vault pattern -- inject secrets at runtime:

# Store a secret
vault kv put secret/myapp/db \
  username="app_user" \
  password="$(openssl rand -base64 32)"

# Read a secret (application startup)
vault kv get -format=json secret/myapp/db | jq -r '.data.data.password'

# Enable audit logging
vault audit enable file file_path=/var/log/vault-audit.log

Kubernetes secrets -- from Vault using sidecar injector:

Annotate the pod template with vault.hashicorp.com/agent-inject: "true", specify the role and secret path. The Vault agent sidecar renders secrets to /vault/secrets/ and the app sources them at startup. Key annotations: agent-inject-secret-<name> for the path, agent-inject-template-<name> for the rendering template.

Secret rotation checklist:

• Generate new secret value
• Update secret in secrets manager
• Restart/reload affected services (rolling, not all-at-once)
• Verify services authenticate with new secret
• Revoke the old secret value
• Confirm no services are still using the old secret

Container Security Scanning

# Scan image for vulnerabilities (Trivy) -- fail CI on critical
trivy image --exit-code 1 --severity CRITICAL registry.example.com/myapp:$CI_COMMIT_SHA

# Scan K8s cluster for misconfigurations
trivy k8s --report summary cluster

Dockerfile security essentials: use pinned base image tags (not :latest), run as non-root (USER app), copy only needed files, never bake secrets into image layers.

Network Security Policies

Kubernetes NetworkPolicy -- default deny with explicit allow:

# Default deny all ingress, then allow specific paths
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-gateway-to-orders
  namespace: production
spec:
  podSelector:
    matchLabels: { app: order-service }
  ingress:
    - from:
        - podSelector:
            matchLabels: { app: api-gateway }
      ports:
        - { protocol: TCP, port: 8080 }

Apply a default-deny-ingress policy (empty podSelector, policyTypes: [Ingress]) per namespace first, then layer allow rules on top.

Compliance as Code

Policy enforcement with OPA/Gatekeeper: use K8sRequiredResources constraints to enforce limits.cpu, limits.memory, requests.cpu, requests.memory on all pods in production namespaces.

Quick compliance audit commands:

# Find pods without resource limits
kubectl get pods -A -o json | jq -r '.items[] | select(.spec.containers[].resources.limits == null) | .metadata.namespace + "/" + .metadata.name'
# Find containers running as root
kubectl get pods -A -o json | jq -r '.items[] | select(.spec.containers[].securityContext.runAsNonRoot != true) | .metadata.namespace + "/" + .metadata.name'
# Find ingress without TLS
kubectl get ingress -A -o json | jq -r '.items[] | select(.spec.tls == null) | .metadata.namespace + "/" + .metadata.name'

Automation Patterns

Auto-Remediation

Restart on OOM (Kubernetes):

# Built-in: set resource limits and let K8s handle OOM restarts
apiVersion: apps/v1
kind: Deployment
spec:
  template:
    spec:
      containers:
        - name: myapp
          resources:
            limits:
              memory: "512Mi"
            requests:
              memory: "256Mi"
          # Liveness probe: restart if unhealthy
          livenessProbe:
            httpGet:
              path: /health
              port: 8080
            initialDelaySeconds: 10
            periodSeconds: 10
            failureThreshold: 3

Scale on load (HPA with custom metrics):

apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: order-service
spec:
  scaleTargetRef: { apiVersion: apps/v1, kind: Deployment, name: order-service }
  minReplicas: 3
  maxReplicas: 20
  behavior:
    scaleUp:   { stabilizationWindowSeconds: 60,  policies: [{ type: Percent, value: 50, periodSeconds: 60 }] }
    scaleDown: { stabilizationWindowSeconds: 300, policies: [{ type: Percent, value: 25, periodSeconds: 120 }] }
  metrics:
    - type: Resource
      resource: { name: cpu, target: { type: Utilization, averageUtilization: 70 } }
    - type: Pods
      pods: { metric: { name: http_requests_per_second }, target: { type: AverageValue, averageValue: "1000" } }

Rotate secrets on expiry (CronJob):

Use a K8s CronJob (e.g., monthly "0 2 1 * *") with a secret-rotator service account that: generates new password -> updates Vault -> alters DB role password -> triggers rolling restart via kubectl rollout restart.

GitOps Workflow

Repository as source of truth:

infrastructure-repo/
  |-- apps/
  |   |-- order-service/
  |   |   |-- deployment.yaml
  |   |   |-- service.yaml
  |   |   |-- hpa.yaml
  |   |   `-- kustomization.yaml
  |   `-- payment-service/
  |       |-- deployment.yaml
  |       `-- kustomization.yaml
  |-- base/
  |   |-- namespace.yaml
  |   |-- network-policies.yaml
  |   `-- resource-quotas.yaml
  `-- overlays/
      |-- staging/
      |   `-- kustomization.yaml
      `-- production/
          `-- kustomization.yaml

Reconciliation loop (ArgoCD application):

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: order-service
  namespace: argocd
spec:
  project: default
  source:
    repoURL: https://github.com/org/infrastructure-repo.git
    targetRevision: main
    path: apps/order-service
  destination: { server: "https://kubernetes.default.svc", namespace: production }
  syncPolicy:
    automated: { prune: true, selfHeal: true }
    syncOptions: [CreateNamespace=true]
    retry: { limit: 3, backoff: { duration: 5s, factor: 2, maxDuration: 3m } }

GitOps deployment flow:

Developer pushes image tag update to infrastructure-repo
  |
  v
ArgoCD detects drift between git state and cluster state
  |
  v
ArgoCD syncs: applies manifests from git to cluster
  |
  v
Kubernetes rolls out new pods
  |
  v
ArgoCD verifies health (readiness probes pass)
  |
  [HEALTHY] --> Done
  [DEGRADED] --> ArgoCD marks sync as failed, alerts on-call

Database Backup and Restore

Automated backup (PostgreSQL) -- run via cron 0 */6 * * *:

#!/bin/bash
set -euo pipefail
TIMESTAMP=$(date +%Y%m%d_%H%M%S)
DB_NAME="production"
BACKUP_DIR="/backups/postgres"

pg_dump -Fc -Z 9 "$DB_NAME" > "${BACKUP_DIR}/${DB_NAME}_${TIMESTAMP}.dump"
aws s3 cp "${BACKUP_DIR}/${DB_NAME}_${TIMESTAMP}.dump" \
  "s3://backups-bucket/postgres/" --storage-class STANDARD_IA
find "$BACKUP_DIR" -name "*.dump" -mtime +30 -delete

Restore procedure:

#!/bin/bash
set -euo pipefail
BACKUP_FILE=$1  # e.g., "production_20250315_060000.dump"
RESTORE_DB="production_restore"

aws s3 cp "s3://backups-bucket/postgres/$BACKUP_FILE" /tmp/restore.dump
psql -c "DROP DATABASE IF EXISTS $RESTORE_DB;" && psql -c "CREATE DATABASE $RESTORE_DB;"
pg_restore -d "$RESTORE_DB" -j 4 --no-owner /tmp/restore.dump
# Verify: check row counts on key tables, then clean up
rm /tmp/restore.dump

Disaster Recovery Runbook Template

Recovery Objectives: Define RTO (e.g., 1 hour) and RPO (e.g., 6 hours) per service.

Prerequisites: backup storage access, Terraform state access, DNS management access, stakeholder comms channel.

Communication template: Subject [INCIDENT] Service -- Status. Body: what happened, impact, current status, ETA, next update time.

Post-recovery checklist: health checks passing, data integrity verified, monitoring restored, backups resumed, incident report filed, post-mortem scheduled within 48h.

Auto-Evolution Workflow

The Phase 7 evolution loop (gated by auto_evolve = true) periodically scans the repos listed in evolution_repos and takes one of three actions per item:

• Open PR → review via the code-reviewer sub-agent, post a COMMENT review back to GitHub.
• Open Issue → triage, then dispatch to the implementer sub-agent if actionable.
• Anything we've already processed at the same head_sha / issue revision → skip.

The pipeline never marks PRs ready-for-review and never pushes to protected branches. All produced PRs are drafts.

When the loop fires

schedule_create registers a recurring trigger on evolution_check_interval. Each tick runs at most one full repo pass; if there's more work than fits in the token budget, the remainder waits for the next tick. The state cursor lives in memory so progress survives daemon restarts.

Memory keys this workflow owns

Events this workflow publishes

These are advisory; subscribers (dashboard, audit log, downstream Hands) are optional.

Issue Triage Playbook

The goal is to spend zero LLM tokens when labels are enough. LLM fallback is one prompt, never a multi-turn chain.

Step 1 -- Label-driven (deterministic)

Has any of {"bug", "defect", "regression", "broken"}        -> bug-fix
Has any of {"feature", "enhancement", "rfc", "proposal"}    -> feature
Has any of {"question", "discussion", "support"}            -> needs-info
Has any of {"wontfix", "duplicate", "invalid", "stale"}     -> skip

Step 2 -- LLM fallback (only when labels are absent)

Single classification prompt. Allowed outputs: exactly one of bug-fix | feature | needs-info | skip. Reject any longer answer and re-prompt once before defaulting to needs-info.

You are classifying a GitHub issue for a DevOps Hand evolution pipeline.

Output exactly ONE token from this set: bug-fix | feature | needs-info | skip

Heuristics:
- bug-fix:    user reports incorrect behavior, crash, regression, security issue,
              or unexpected output of existing functionality.
- feature:    user requests new capability, configuration option, or refactor
              that ships user-visible value.
- needs-info: report is ambiguous -- cannot reproduce, missing version/environment,
              cannot tell if bug or feature.
- skip:       issue is a question, off-topic, or already addressed.

Issue title: {TITLE}
Issue body:
{BODY}
Existing labels: {LABELS_OR_NONE}

Step 3 -- Already-linked PR check

# A PR already references this issue -> skip implementation, just review the PR
curl -s -H "Authorization: Bearer $GITHUB_TOKEN" \
  "https://api.github.com/repos/OWNER/REPO/issues/NUM/timeline?per_page=50" \
  | jq '.[] | select(.event == "cross-referenced") | .source.issue.pull_request.url'

PR Review Automation

Pull PR metadata + diff + files in three calls

PR_URL="https://api.github.com/repos/OWNER/REPO/pulls/NUM"

curl -s -H "Authorization: Bearer $GITHUB_TOKEN" "$PR_URL" -o pr.json
curl -s -H "Authorization: Bearer $GITHUB_TOKEN" \
     -H "Accept: application/vnd.github.v3.diff" \
     "$PR_URL" -o pr.diff
curl -s -H "Authorization: Bearer $GITHUB_TOKEN" "$PR_URL/files?per_page=300" -o pr_files.json

Short-circuit on bot / merge / huge diff

Extract the cheap signals from already-fetched PR metadata:

HEAD_SHA=$(jq -r .head.sha pr.json)
USER_TYPE=$(jq -r .user.type pr.json)
CHANGED=$(jq '. | length' pr_files.json)

Decision rules (the agent applies these in its loop, not the shell — exit 0 would only end one shell_exec, not abort the Phase 7 pass):

• USER_TYPE == "Bot" (dependabot, renovate, etc.): skip deep review for this PR. The agent then:
  1. calls memory_store devops_pr_review_<owner>_<repo>_<num> with {head_sha, verdict: "skipped_bot", timestamp}
  2. calls event_publish devops_evolution_skipped with {pr_or_issue_url, reason: "bot author"}
  3. moves on to the next PR — does NOT dispatch the reviewer sub-agent.
• CHANGED > 200: diff too large for the reviewer to ground usefully. The agent then:
  1. calls event_publish devops_evolution_skipped with {pr_or_issue_url, reason: "diff>200 files"}
  2. moves on to the next PR.

Dispatch to reviewer sub-agent

Hand the reviewer the diff, file list, PR description, and (if present) the target branch's AGENTS.md / CONTRIBUTING.md. Capture the reviewer's structured JSON into reviewer_output.json (whatever your routing primitive is — subagent_invoke, A2A call, or local fork — write the result to that file so the next shell snippet can read it):

{
  "verdict": "approve | request_changes | block | comment_only",
  "issues": [
    {"severity": "critical|major|minor", "file": "...", "line": 42, "body": "..."}
  ],
  "positives": ["..."],
  "summary": "..."
}

Post a single review (not N inline comments)

# Pull verdict + summary out of the reviewer's structured output.
VERDICT=$(jq -r .verdict reviewer_output.json)
SUMMARY_BODY=$(jq -r .summary reviewer_output.json)

# Map verdict -> GitHub review event. Never auto-APPROVE.
BODY_PREFIX=""
case "$VERDICT" in
  approve)
    # Downgrade silent "approve" to advisory COMMENT — a human still merges.
    EVENT="COMMENT"
    ;;
  request_changes)
    EVENT="REQUEST_CHANGES"
    ;;
  block)
    # Block is more severe than request_changes. We still post REQUEST_CHANGES
    # (the strongest event we use), but flag the body so a human escalates.
    EVENT="REQUEST_CHANGES"
    BODY_PREFIX="**Reviewer flagged this PR as BLOCKING — please escalate to a maintainer before merge.**

"
    ;;
  comment_only|*)
    EVENT="COMMENT"
    ;;
esac
SUMMARY_BODY="${BODY_PREFIX}${SUMMARY_BODY}"

jq -n --arg event "$EVENT" --arg body "$SUMMARY_BODY" --arg sha "$HEAD_SHA" \
  '{commit_id: $sha, event: $event, body: $body}' > review_payload.json

curl -s -X POST -H "Authorization: Bearer $GITHUB_TOKEN" \
  -H "Content-Type: application/json" \
  -d @review_payload.json \
  "$PR_URL/reviews"

Body format -- keep tight; reviewers read this:

**DevOps Hand -- automated review**

**Verdict**: {verdict}

**Summary**: {one paragraph}

**Findings** ({N}):
- [critical] {file}:{line} -- {body}
- [major]    {file}:{line} -- {body}
- [minor]    {file}:{line} -- {body}

**What looks good**:
- {positive 1}

_Generated by DevOps Hand reviewer (commit: `{sha}`)._

Bug Fix Playbook

The implementer runs this when classification = "bug-fix". Sequence is rigid -- failing test first, fix second, refactor third.

Step 1 -- Reproduce

In the supplied worktree:

cd "$REPO_CONTEXT"
git checkout -b "auto/bug-fix-${ISSUE_NUMBER}-${SLUG}"
# Try to reproduce from the issue's repro steps. If they're absent, infer them.
# If you cannot reproduce in 3 attempts, stop and surface to devops_queue.json.

Step 2 -- Failing test first

# For Rust workspaces, drop the test in the closest existing module's tests/.
cargo test -p <crate> --test <existing_test_file> -- --nocapture --test-threads=1
# Expect FAILURE. Commit the failing test:
git add tests/ && git commit -m "test: reproduce #${ISSUE_NUMBER} -- <one-line>"

Step 3 -- Minimal fix

Edit only the files needed to make the test pass. Run the project's full lint+test gate:

cargo clippy --workspace --all-targets -- -D warnings
cargo test -p <crate>                  # not --workspace -- target/ contention

Step 4 -- Refactor (optional)

Only if step 3 left obvious smell (long fn, repeated literal, etc.). Skip if bmad_strictness = "light".

Step 5 -- Commit and push (draft branch only)

git add -A && git commit -m "fix: <subject> (#${ISSUE_NUMBER})"
git push origin "auto/bug-fix-${ISSUE_NUMBER}-${SLUG}"

Step 6 -- Open draft PR (see Draft PR Creation below)

BMAD Feature Pipeline

Run when classification = "feature". Phases scale with bmad_strictness:

Each phase output is appended to BMAD.md in the repo root of the feature branch. The file is committed along with the implementation so reviewers can see the reasoning.

BMAD.md template

# BMAD -- #{ISSUE_NUMBER}: {SHORT TITLE}

## Brainstorm
**Restated problem**: {one paragraph}

**Approaches considered**:
1. **{Name}** -- {sketch} -- files: {list} -- risk: {low/mid/high} -- diff: ~{N} LoC
2. **{Name}** -- ...
3. **{Name}** -- ...

**Chosen**: #{N}. Rationale: {one paragraph}

## Architecture
**Crates / modules touched**: {list}

**Types / signatures introduced or changed**:
```rust
// ...
```

**Cross-crate ripples**: {none / bounded list / escalated to queue: reason}

## PRD
**Acceptance criteria**
- [ ] {behavior 1}
- [ ] {behavior 2}

**Test plan**
- unit: `crates/{crate}/src/{path}.rs` -- {what it asserts}
- integration: `crates/{crate}/tests/{name}.rs` -- {what it asserts}

**Rollback plan**: {one paragraph}

## Implementation Notes
{anything a future reader needs to understand the diff but wouldn't see in code comments}

Strict mode queue gate

Between each phase, write to devops_queue.json:

{
  "id": "bmad_${REPO}_${ISSUE}_${PHASE}",
  "action": "bmad_phase_review",
  "phase": "B|A|P|I",
  "issue": "owner/repo#NUM",
  "artifact_path": "BMAD.md",
  "status": "pending",
  "created": "ISO8601"
}

Then end the current turn. The Hand is frequency = "continuous", so the next tick will re-read devops_queue.json:

• If the user (out-of-band) has flipped status to approved, resume from the next phase.
• If still pending, skip this issue for this tick and re-check on the following one.
• If flipped to rejected, abandon the issue, comment on it with the rejection rationale (if provided), and stop.

Within a single turn, never poll or sleep waiting for approval — the agent loop has no in-turn pause primitive, and busy-waiting would block other Hand work and burn tokens. End the turn and let the kernel re-invoke you.

Draft PR Creation

The final action of both bug-fix and feature paths. Always draft: true.

Step 1 -- Push the branch (if not already)

git push origin "auto/${CLASSIFICATION}-${ISSUE}-${SLUG}"

Step 2 -- Compose the PR body

## Summary
{one paragraph}

## Linked Issue
Closes #{ISSUE_NUMBER}

## BMAD Pipeline Output
{inline BMAD.md, or note that it's committed at `BMAD.md` in this PR}

## Acceptance Checklist
- [ ] {copied from PRD}

## Risk
{one paragraph -- what could go wrong, what's the blast radius}

## Verification I ran locally
- `cargo clippy --workspace --all-targets -- -D warnings` -- passed
- `cargo test -p {crate}` -- passed
- {anything project-specific from justfile / xtask}

## Generated by
DevOps Hand -> implementer  (strictness: {level})

Step 3 -- Open the draft PR

First resolve the target branch. Don't assume main -- query the repo:

BASE_BRANCH=$(curl -s -H "Authorization: Bearer $GITHUB_TOKEN" \
  "https://api.github.com/repos/${OWNER}/${REPO}" | jq -r .default_branch)
# fallback in the unlikely case the API doesn't return one
[ -z "$BASE_BRANCH" ] || [ "$BASE_BRANCH" = "null" ] && BASE_BRANCH="main"

Then create the draft PR:

jq -n \
  --arg title "${PR_TITLE}" \
  --arg body  "${PR_BODY}" \
  --arg head  "auto/${CLASSIFICATION}-${ISSUE}-${SLUG}" \
  --arg base  "${BASE_BRANCH}" \
  '{title: $title, body: $body, head: $head, base: $base, draft: true}' \
  > pr_create.json

curl -s -X POST -H "Authorization: Bearer $GITHUB_TOKEN" \
  -H "Content-Type: application/json" \
  -d @pr_create.json \
  "https://api.github.com/repos/${OWNER}/${REPO}/pulls" \
  -o pr_created.json

PR_URL=$(jq -r .html_url pr_created.json)
echo "Draft PR: $PR_URL"

Step 4 -- Cross-link on the originating issue

Build the body in shell first so newlines survive (jq --arg is a literal-string parameter, it does NOT interpret backslash escapes):

ISSUE_COMMENT=$(printf 'Auto-implementation drafted: %s\n\n_Generated by DevOps Hand. Mark the PR ready-for-review when human triage agrees._' "$PR_URL")

jq -n --arg body "$ISSUE_COMMENT" '{body: $body}' > issue_comment.json

curl -s -X POST -H "Authorization: Bearer $GITHUB_TOKEN" \
  -H "Content-Type: application/json" \
  -d @issue_comment.json \
  "https://api.github.com/repos/${OWNER}/${REPO}/issues/${ISSUE_NUMBER}/comments"

Step 5 -- Bump counters

memory_store devops_hand_draft_prs_opened (current + 1)
memory_st

…(truncated)