fix(deploy): honor aws-targets.json region for all SDK and CDK calls

[aidandaly24]

Description

The agentcore CLI did not use the region field from aws-targets.json when making API calls for resources like runtimes, evaluators, and online eval configs. Changing aws-targets.json had no effect on where resources were created unless AWS_DEFAULT_REGION was also set.

Root cause

The CLI passes target.region explicitly to its own SDK clients, but @aws-cdk/toolkit-lib constructs internal SDK clients (for CloudFormation, S3 asset upload, asset publishing, etc.) that do not receive an explicit region option and fall back to the SDK default region resolution chain: AWS_REGION → AWS_DEFAULT_REGION → shared config profile. When aws-targets.json specified a non-default region but those env vars were unset, CDK's internal clients resolved the wrong region and resources were created in the SDK default region.

Fix

New helper src/cli/aws/target-region.ts exports:

• applyTargetRegionToEnv(region) — sets AWS_REGION and AWS_DEFAULT_REGION to the target region, returns a restore function.
• withTargetRegion(region, fn) — try/finally wrapper.

Applied at:

• src/cli/commands/deploy/actions.ts — handleDeploy() calls applyTargetRegionToEnv(target.region) after target resolution; restore runs in the existing finally block.
• src/cli/operations/deploy/teardown.ts — destroyTarget() wraps CDK initialize()/destroy() in withTargetRegion(...).
• src/cli/tui/hooks/useCdkPreflight.ts — TUI path applies the override after validateProject(); restored on unmount, cancelTeardown, preflight retry, SIGINT/SIGTERM.

Invoke/status/eval/logs commands already pass target.region explicitly to every SDK client — no changes needed there.

Related Issue

Closes #924

Documentation PR

N/A — behavior-only fix.

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Other (please describe):

Testing

How have you tested the change?

• I ran `npm run test:unit` and `npm run test:integ`
• I ran `npm run typecheck`
• I ran `npm run lint`
• If I modified `src/assets/`, I ran `npm run test:update-snapshots` and committed the updated snapshots

Unit tests

7 new unit tests in `src/cli/aws/tests/target-region.test.ts` cover:

• sets both env vars to the provided region
• restore clears env vars when they were previously unset
• restore preserves previous values when they were set
• restore handles each env var independently
• applies inside callback and restores afterwards
• restores even when the callback throws
• returns the callback result

All 7 pass. Relevant targeted suites (aws, operations/deploy, config-io, tui/hooks): 354/354 pass. tsc: 0 errors. eslint: 0 errors on modified files.

End-to-end testing against live AWS

Tested full lifecycle (create → add agent → deploy → invoke → teardown) against AWS account 603141041947 across 5 scenarios:

#	Scenario	Region	Result
1	CLI non-interactive, no env vars	`ap-southeast-2`	✅ Runtime in apse2, none in us-east-1
2	Env isolation — success + error paths	`ap-southeast-2`	✅ Env vars remain unset after both paths
3	CLI non-interactive, no env vars	`eu-west-1`	✅ Runtime in euw1, invoke returned "Hello!"
4	Interactive TUI (tui-harness)	`ap-southeast-2`	✅ Full interactive deploy + teardown
5	Key test: target beats env var	`eu-west-2` + `AWS_DEFAULT_REGION=us-east-1`	✅ Runtime in euw2, none in us-east-1

All 5 verified via `aws bedrock-agentcore-control list-agent-runtimes` and teardown confirmed cleanup.

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[github-actions]

Package Tarball

aws-agentcore-0.9.1.tgz

How to install

npm install https://github.com/aws/agentcore-cli/releases/download/pr-925-tarball/aws-agentcore-0.9.1.tgz

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	42.02%	7241 / 17229
🔵	Statements	41.44%	7675 / 18518
🔵	Functions	40.13%	1283 / 3197
🔵	Branches	40.49%	4826 / 11917

Generated in workflow #1892 for commit f2bfd20 by the Vitest Coverage Report Action

[notgitika]

Nice fix — the approach of promoting the target region onto env vars is the right call since CDK toolkit-lib's internal clients don't take an explicit region.

Two small things:

1. TUI error states don't restore the env override — when run() errors out after the region override is applied (e.g. build/synth/stack-status failures), we call setPhase('error') but never call restoreRegionEnv(). It stays overridden until the user retries or unmounts. Probably fine in practice since the TUI is short-lived, but a small useEffect guard would close this gap cleanly:

   useEffect(() => {
     if (phase === 'error') restoreRegionEnv();
   }, [phase, restoreRegionEnv]);

2. Minor export inconsistency — withTargetRegion is exported from the barrel (aws/index.ts) but applyTargetRegionToEnv is imported directly from target-region.ts in both actions.ts and useCdkPreflight.ts. Not a big deal, just noticed the mismatch — either export both from the barrel or import both directly.

Everything else looks solid — tests are thorough, the teardown double-wrapping is a nice defensive touch, and the env var save/restore logic correctly handles the undefined vs set distinction.