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# sincecutoff.com changes: cdk

## cdk init accepts custom project names with --project (cdk, 2026-01-15)
Published 2026-10-19
- slug: cdk-init-accepts-custom-project-names-with-project-00fab97c09bf
- score: 0.99

How to use it:

When initializing a CDK project with a custom name, run `cdk init` with a template, language, and `-n <project-name>`. The versioned source documents the long option as `--project-name` (the release note says `--project`).

Examples:

```
cdk init app --language=typescript -n <project-name>
```

- why_it_matters: Initialize a CDK project with a custom project name.
- sources: <https://github.com/aws/aws-cdk-cli/releases/tag/aws-cdk%40v2.1101.0>, <https://github.com/aws/aws-cdk-cli/commit/29249acbc143fcaa0080094a5d472408b6ebc4c1>, <https://docs.aws.amazon.com/cdk/v2/guide/ref-cli-cmd-init.html>, <https://github.com/aws/aws-cdk-cli/blob/aws-cdk%40v2.1101.0/packages/aws-cdk/README.md>
- gotchas: "Version: 2.1101.0"; "template (`app`, `lib`, or `sample-app`) (required): Template type for the new project."; "`--language`, `-l`: Language for the new project; valid values include `typescript`."; "`--project-name`, `-n`: Name of the new project; requires a string argument. The source gives no default value."; "Prerequisite: Node.js or another JavaScript runtime is required; versioned CLI README specifies Node.js v18 as the minimum supported version."; "Docs conflict: The release note names the long option `--project`; the versioned source defines `project-name` with alias `n`."

## cdk hotswap deploys Bedrock AgentCore Runtime changes (cdk, 2026-01-22)
Published 2026-10-19
- slug: cdk-hotswap-deploys-bedrock-agentcore-runtime-changes-e2509f14691d
- score: 0.94

How to use it:

When an AWS::BedrockAgentCore::Runtime change is supported, run `cdk deploy <stack-id> --hotswap`; the CLI attempts a direct hotswap, and unsupported changes are ignored. For S3 code changes, use `Asset` from `aws-cdk-lib/aws-s3-assets` so the object key changes with the content hash.

Examples:

```
cdk deploy <stack-id> --hotswap
```

```
const asset = new aws_s3_assets.Asset(this, 'CodeAsset', { path: path.join(__dirname, 'agent-code') });
const agentRuntimeArtifact = AgentRuntimeArtifact.fromS3({ bucketName: asset.s3BucketName, objectKey: asset.s3ObjectKey }, AgentCoreRuntime.PYTHON_3_13, ['app.py']);
new Runtime(this, 'Runtime', { runtimeName: 'runtime', agentRuntimeArtifact });
```

- why_it_matters: When updating an AWS::BedrockAgentCore::Runtime in a CDK app, deploy supported runtime changes with hotswap.
- sources: <https://github.com/aws/aws-cdk-cli/releases/tag/aws-cdk%40v2.1102.0>, <https://github.com/aws/aws-cdk-cli/pull/991>, <https://docs.aws.amazon.com/cdk/v2/guide/ref-cli-cmd-deploy.html>
- gotchas: "Version: v2.1102.0"; "<stack-id>: CDK stack construct ID to deploy."; "--hotswap <BOOLEAN>: Attempt a hotswap deployment; default is false. Unsupported changes are ignored with a message. Uses current AWS credentials and does not assume bootstrap roles."; "Asset.path (required): Path to the asset directory in the release-note S3 example."; "AgentRuntimeArtifact.fromS3 bucketName (required): S3 bucket name supplied to the artifact in the release-note example."; "AgentRuntimeArtifact.fromS3 objectKey (required): S3 object key; example uses `asset.s3ObjectKey`, described as a content hash that changes when code changes."; "AgentRuntimeArtifact.fromS3 runtime (required): Runtime identifier; example uses `AgentCoreRuntime.PYTHON_3_13`."; "AgentRuntimeArtifact.fromS3 entry points (required): Example passes `['app.py']`."; "Prerequisite: Use AWS credentials for the same account as the stacks and with IAM permissions to update the resources directly."; "Prerequisite: Hotswap is intended for development; it deliberately introduces CloudFormation drift and is not recommended for production."; "S3 code changes are detected when using `Asset` from `aws-cdk-lib/aws-s3-assets`."; "Do not use `Source.asset()` with `BucketDeployment` for S3 code changes: the generated object key is a token resolved at deployment time and does not change in the CloudFormation template, so hotswap will not work."; "Docs conflict: Current AWS CDK CLI reference lists Bedrock AgentCore Runtime support as configuration changes; it does not enumerate the release-note's code files, container image, environment variable, or description change categories. The reference page may describe a newer CLI version than v2.1102.0. No conflicting details used."

## cdk deploy supports concurrent asset builds (cdk, 2026-03-04)
Published 2026-10-19
- slug: cdk-deploy-supports-concurrent-asset-builds-0fa1b7c29f17
- score: 0.98

How to use it:

When deploying a CDK app with multiple assets, run `cdk deploy --asset-build-concurrency 4` to parallelize asset builds.

Examples:

```
cdk deploy --asset-build-concurrency 4
```

- why_it_matters: When deploying a CDK app with multiple assets, build assets in parallel.
- sources: <https://github.com/aws/aws-cdk-cli/releases/tag/aws-cdk%40v2.1109.0>, <https://github.com/aws/aws-cdk-cli/pull/983>
- gotchas: "Version: 2.1109.0"; "--asset-build-concurrency 4: Sets the asset build concurrency to 4. The release note gives this invocation but does not document the option’s accepted values or default."; "Docs conflict: The current AWS `cdk deploy` reference documents `--asset-parallelism <BOOLEAN>` for parallel asset builds, not `--asset-build-concurrency`. It may describe a newer CLI version; the release note for v2.1109.0 names `--asset-build-concurrency`. https://docs.aws.amazon.com/cdk/v2/guide/ref-cli-cmd-deploy.html"

## CDK CLI adds --revert-drift option (cdk, 2026-03-09)
Published 2026-10-19
- slug: cdk-cli-adds-revert-drift-option-13c62ec8ede2
- score: 0.94

How to use it:

When reconciling out-of-band resource changes with CDK template definitions, deploy the affected stack with the drift-aware change set option. Run `cdk deploy <stack> --revert-drift`.

Examples:

```
cdk deploy <stack> --revert-drift
```

- why_it_matters: When reconciling actual resource state with CDK template definitions, use the CLI drift-revert option.
- sources: <https://github.com/aws/aws-cdk-cli/releases/tag/aws-cdk%40v2.1110.0>, <https://docs.aws.amazon.com/cdk/v2/guide/ref-cli-cmd-deploy.html>
- gotchas: "Version: 2.1110.0"; "<stack>: CDK stack ID to deploy; omit to deploy according to the app's stack selection behavior."; "--revert-drift: Uses a CloudFormation `REVERT_DRIFT` change set to detect out-of-band drift and revert resources to their template-defined state. Default: false."; "Prerequisite: CDK CLI and a CDK app with the target stack. If the AWS environment is not bootstrapped, only stacks without assets and with synthesized templates under 51,200 bytes can successfully deploy."

## cdk destroy adds --concurrency (cdk, 2026-03-18)
Published 2026-10-19
- slug: cdk-destroy-adds-concurrency-045f20c4cdc3
- score: 0.90

How to use it:

When destroying all CDK stacks, set `--concurrency` to the maximum number of simultaneous destroy operations. Stack dependencies are respected, but AWS rate limits still apply.

Examples:

```
cdk destroy --all --concurrency <N>
```

- why_it_matters: Set concurrency when destroying CDK stacks during repository cleanup.
- sources: <https://github.com/aws/aws-cdk-cli/releases/tag/aws-cdk%40v2.1112.0>, <https://docs.aws.amazon.com/cdk/v2/guide/ref-cli-cmd-destroy.html>, <https://github.com/aws/aws-cdk-cli/blob/403fe8ea33c2865ebe0e21558d706bc5f5037f60/packages/aws-cdk/README.md>
- gotchas: "Version: v2.1112.0"; "--concurrency <NUMBER>: Maximum simultaneous destroy operations, subject to stack dependencies; default is 1."; "--all <BOOLEAN>: Destroy all available stacks; default is false."; "Prerequisite: Requires Node.js or another JavaScript runtime; the release-era CLI README lists Node.js v18 as the minimum supported version."

## cdk diff adds --method to enforce change set usage (cdk, 2026-03-30)
Published 2026-10-19
- slug: cdk-diff-adds-method-to-enforce-change-set-usage-bbf32a1a0140
- score: 0.96

How to use it:

When a stack diff must always use a CloudFormation change set, run `cdk diff <stack-id> --method=change-set`. The command fails if it cannot create the change set.

Examples:

```
cdk diff <stack-id> --method=change-set
```

- why_it_matters: When reviewing a CDK stack diff that must use a change set, enforce change set usage.
- sources: <https://github.com/aws/aws-cdk-cli/releases/tag/aws-cdk%40v2.1115.0>, <https://github.com/aws/aws-cdk-cli/blob/23bc301a65086c4b68ad63e94b5cc80aa521fdbc/packages/aws-cdk/README.md>, <https://docs.aws.amazon.com/cdk/v2/guide/ref-cli-cmd-diff.html>
- gotchas: "Version: v2.1115.0"; "<stack-id>: CDK stack construct ID to diff."; "--method=change-set: Always creates a CloudFormation change set and fails if it cannot be created; uses the deploy role. Allowed `--method` values documented: `auto` (default), `change-set`, `template`."

## cdk publish-assets publishes stack assets without deployment (cdk, 2026-04-01)
Published 2026-10-19
- slug: cdk-publish-assets-publishes-stack-assets-without-deployment-6c02585d6bfa
- score: 0.94

How to use it:

When a CI/CD workflow separates asset publishing from deployment, use the under-development `publish-assets` command to publish assets for the target stack without deploying it.

Examples:

```
cdk publish-assets <stack> --unstable=publish-assets
```

```
cdk publish-assets --all --unstable=publish-assets
```

```
cdk publish-assets <stack> --unstable=publish-assets --force
```

- why_it_matters: In a CI/CD workflow that separates asset publishing from deployment, publish assets for the target CDK stack without deploying it.
- before: Use `cdk deploy`, which combines asset publishing and stack deployment into a single operation.
- sources: <https://github.com/aws/aws-cdk-cli/releases/tag/aws-cdk%40v2.1116.0>, <https://github.com/aws/aws-cdk-cli/pull/1020>, <https://github.com/aws/aws-cdk-cli/blob/main/packages/aws-cdk/README.md>
- gotchas: "Version: v2.1116.0"; "Availability: Under development; opt in with `--unstable=publish-assets`. The scope and API might still change."; "<stack>: Stack name; used to select the target stack. Omit when using `--all`."; "--unstable=publish-assets (required): Opts in to the under-development `publish-assets` command."; "--all: Select all stacks."; "--force: Force republishing even if assets already exist."; "Prerequisite: The command is under development; opt in with `--unstable=publish-assets`."; "Publishes assets for specified stack(s) without performing deployment."

## cdk CLI adds global --region option (cdk, 2026-05-19)
Published 2026-10-19
- slug: cdk-cli-adds-global-region-option-98daf7ca7da7
- score: 0.97

How to use it:

When a CDK CLI command needs a specific AWS Region, pass `--region <region>` with the command. The CLI uses that Region for deployment operations and context lookup during synthesis.

Examples:

```
cdk <command> --region <region>
```

- why_it_matters: When running a CDK CLI command for a repository app that needs a specific region, pass the global region option.
- sources: <https://github.com/aws/aws-cdk-cli/releases/tag/aws-cdk%40v2.1123.0>, <https://docs.aws.amazon.com/cdk/v2/guide/cli.html>, <https://github.com/aws/aws-cdk-cli/blob/main/packages/aws-cdk/README.md>
- gotchas: "Version: 2.1123.0"; "--region <region>: AWS Region to use; the command-line value takes precedence over other Region sources."; "Prerequisite: Install the AWS CDK CLI with npm. Region and AWS authentication are needed for deployment operations and to retrieve context values during synthesis."

## toolkit-lib DeployResult reports resource delete failures (cdk, 2026-06-03)
Published 2026-10-19
- slug: toolkit-lib-deployresult-reports-resource-delete-failures-a93471b02618
- score: 0.90

How to use it:

When using toolkit-lib to deploy a stack, inspect `deleteFailures` on the successful stack result; it lists resources CloudFormation failed to delete during a stack update. [Source](https://github.com/aws/aws-cdk-cli/blob/aws-cdk%40v2.1126.0/packages/%40aws-cdk/toolkit-lib/lib/api/deployments/deployment-result.ts)

Examples:

```
const result = await toolkit.deploy(...); // pass the deployment arguments required by your application
for (const stack of result.stackResults) {
  if (stack.type === 'did-deploy-stack') {
    for (const failure of stack.deleteFailures) {
      // inspect failure
    }
  }
}
```

- why_it_matters: When programmatically deploying a stack that may leave resources undeleted, inspect the deployment result for CloudFormation delete failures.
- before: Programmatic consumers of `toolkit-lib` and integration tests could not observe this condition; CloudFormation could silently skip a failed deletion after retries while marking the update successful.
- sources: <https://github.com/aws/aws-cdk-cli/releases/tag/aws-cdk%40v2.1126.0>, <https://github.com/aws/aws-cdk-cli/pull/1576>, <https://github.com/aws/aws-cdk-cli/blob/aws-cdk%40v2.1126.0/packages/%40aws-cdk/toolkit-lib/lib/api/deployments/deployment-result.ts>
- gotchas: "Version: 2.1126.0"; "deleteFailures (required): `ResourceDeleteFailure[]`; resources CloudFormation failed to delete during a stack update. Non-empty only when CloudFormation skipped deletion failures."; "DeployedStack (required): Not found as a documented type in the opened result file; it defines `SuccessfulDeployStackResult` with `deleteFailures`."; "This reports resource deletions CloudFormation failed to perform during a stack update."

## cdk validate adds an unstable online mode (cdk, 2026-06-15)
Published 2026-10-19
- slug: cdk-validate-adds-an-unstable-online-mode-079c29b3c4e1
- score: 0.93

How to use it:

When checking a CDK project's configuration online, run `cdk validate --online` with the `validate` unstable feature enabled.

Examples:

```
cdk --unstable=validate validate --online
```

- why_it_matters: Validate a CDK project online when checking its configuration.
- sources: <https://github.com/aws/aws-cdk-cli/releases/tag/aws-cdk%40v2.1127.0>, <https://github.com/aws/aws-cdk-cli/blob/main/packages/aws-cdk/README.md>
- gotchas: "Version: 2.1127.0"; "--unstable=validate (required): Opts in to the unstable `validate` command; the CLI global option takes a feature name."; "--online (required): Enables online validation. The official documentation found does not detail this flag's behavior or parameters."; "Prerequisite: Use an AWS CDK CLI version that includes `cdk validate`; the release note introduces the command in v2.1127.0."; "The `cdk validate` command is behind the `--unstable` flag."

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