arc-region-switch

What the source does

• FilesystemNone observedNo reads or writes in the source
• NetworkNone observedNo outbound calls in the source
• ShellNone observedNo commands run in the source
• DependenciesPinnedNothing floats
• SecretsNone foundNo keys in source

Five audit layers

Gates applied: no behavioural pass.

Audit 0.4.1 · source sha 9d0fb564de1b · 31 Oct 2026Report an issue or request a re-scan

• Publisheraws GitHub organizationOwner of the repository this skill is read from
• Source folderaws/agent-toolkit-for-aws/skills/specialized-skills/resilience-skills/arc-region-switchThe exact folder we audited
• LicenceApache-2.0As the repository states it
• Commit pinned for this verdict9d0fb564de1bA new audit runs when the source changes
• Repository statusNot archivedPushed today
• Sandboxed runNot runSkills are read, not executed; layer L4 is skipped

Its description: Answers questions about Amazon Application Recovery Controller (ARC) Region switch including architecture, plans, execution blocks, workflows, triggers, active/active vs active/passive, cross-account support, recovery…

---
name: arc-region-switch
description: "Answers questions about Amazon Application Recovery Controller (ARC) Region switch including architecture, plans, execution blocks, workflows, triggers, active/active vs active/passive, cross-account support, recovery time, dashboards, and customer positioning. Applicable when users ask about ARC Region switch adoption, design, or troubleshooting."
version: 1
---

# ARC Region switch Expert

## Overview

Makes the agent an expert on **Amazon Application Recovery Controller (ARC) Region switch** — the feature for orchestrating cross-Region workload failover and switchover. Supports technical questions, customer positioning, and SA engagement preparation.

Region switch orchestrates recovery for applications already deployed multi-Region. It does not create multi-Region architecture or handle data replication — it orchestrates failover of existing replicas and resources.

## Guardrail — where this skill's own files live (MCP vs local install)

Before reading a reference file, determine how this skill was loaded:

- **Loaded via the AWS MCP `retrieve_skill` tool:** the skill's reference files are not on the local filesystem. Fetch each one through `retrieve_skill` with the `file` parameter (e.g. `file="references/positioning.md"` or `file="references/doc-links.md"`) — do NOT `file_read` these paths locally or search the filesystem for them.
- **Installed locally** (e.g. `.kiro/skills/arc-region-switch/` or `~/.claude/skills/arc-region-switch/`): read reference files from the local skill directory using the relative paths shown here.

This applies only to the skill's own reference files; always read and write user or session data in the working directory, never through `retrieve_skill`.

## When Not to Use

- **In-Region failover** — Region switch is for cross-Region recovery only. Use AZ-level mechanisms (ALB, Auto Scaling) for in-Region resilience.
- **Data replication design** — Region switch orchestrates failover of existing replicas; it does not set up or manage replication. Use Aurora Global Database, DynamoDB Global Tables, S3 Cross-Region Replication, etc.
- **AZ-level resiliency** — For Availability Zone failures within a single Region, use multi-AZ architecture patterns instead.

## Terminology Constraints

- ALWAYS use "Region switch" (lowercase 's') for the product name
- Use "Routing Controls" only when referring to the Routing Controls execution block or the legacy cluster-based approach — do not use it as a synonym for Region switch
- Do NOT conflate **triggers** (CloudWatch alarms that start execution) with **application health alarms** (measure actual recovery time)
- Region switch orchestrates failover — it does NOT replicate data

## Critical Warnings

- **Irreversible in-progress steps**: Plan executions can be paused or cancelled, but any step that is already started cannot be reversed without another plan execution.
- **Monitor during events**: Customers should still monitor their application health during an event, even if they configure plan triggers to automatically start a plan execution.
- **Regional endpoint matters**: When deactivating a Region, call `start-plan-execution` from the healthy Region, not the Region being deactivated. When activating a Region, call from the Region being activated. See [StartPlanExecution API](https://docs.aws.amazon.com/arc-region-switch/latest/api/API_StartPlanExecution.html).

## Workflow

1. Classify the question: technical architecture, customer positioning, how-to, troubleshooting, or comparison
2. Answer from embedded knowledge in this skill
3. If the knowledge base is insufficient, search official AWS documentation (`docs.aws.amazon.com`)
4. Format the response for the audience (engineer, SA, customer)

Always validate:

- Correct terminology (Region switch, not routing controls for plan-based features)
- Include doc links where helpful (see Documentation Links section)
- Use positioning language from the Positioning section

## Architecture

### Components

| Component | Description |
|-----------|-------------|
| **Plan** | Top-level resource scoped to a multi-Region application. Contains workflows. |
| **Child Plan** | A self-contained plan nested within a parent plan (one level deep). |
| **Workflow** | Ordered sequence of steps within a plan. Defines activation/deactivation logic. |
| **Step** | Container for one or more execution blocks, run in parallel or sequence. |
| **Execution Block** | Performs a specific recovery action (e.g., scale up, reroute traffic, failover DB). |
| **Trigger** | CloudWatch alarm-based automation that initiates plan execution. |
| **Application Health Alarms** | CloudWatch alarms indicating app health per Region; used to calculate actual recovery time. |
| **Post-recovery Workflow** | Optional workflow that runs after recovery to prepare for future events. |
| **Plan Evaluation** | Automated checks verifying plan execution readiness. Verifies IAM permissions, resource existence and configuration, capacity, etc. |
| **Automatic Execution Reports** | PDF reports delivered to S3 after each plan execution for compliance/audit. |

### Execution Modes

Recommend using graceful execution unless not possible (e.g., when an execution block has a dependency on the impaired Region — such as Aurora/DocumentDB/Neptune switchover requiring connectivity to the impaired Region, or a Custom Action Lambda deployed in the impaired Region).

- **Graceful**: Runs all steps in orderly sequence. Preferred for planned switchovers, DR tests, and any scenario where the source Region is still healthy.
- **Ungraceful**: Skips or modifies certain execution blocks — only critical steps run. Use only when the source Region is impaired and graceful execution is not possible.
- **Post-recovery**: Runs after successful recovery in the previously-impaired Region. Requires both Regions to be healthy. Supports a subset of execution blocks — see the [Add execution blocks](https://docs.aws

Excerpt, first 6,000 characters of SKILL.md, verbatim from the audited commit. It is text from someone else’s repository, quoted so you can judge it before your agent reads it.

git clone https://github.com/aws/agent-toolkit-for-aws
git -C agent-toolkit-for-aws checkout 9d0fb564de1b

Works in

1. 2026-10-31
   ✓SAFE B 89 / 100

   first audit · source 9d0fb564de1b

Questions about arc-region-switch

• github.com/aws/agent-toolkit-for-aws/tree/main/skills/specialize — the audited source at commit 9d0fb564de1b and every finding aboveObserved · 31 Oct 2026

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