Lab #403: Add a list/discover method to dbcluster for enumerating clusters in a region

The @swamp/aws/rds/dbcluster model currently exposes only single-cluster operations (create / get / update / delete / sync) — all of which require the cluster identifier to already be known. There is no way to enumerate existing clusters in the current account and region.

This is a structural gap for any audit, inventory, or migration workflow. I hit it building a "list Aurora clusters in eu-west-1 with N members" inventory for an r7g → r8g instance class cutover, and ended up writing a separate @jentz/aws-rds-inventory model to do it. Other community extensions (e.g. @webframp/aws/guardduty) ship list-style discovery methods, so the pattern is established.

Implementation scope:

Add a list (or discover) method to the dbcluster model that paginates DescribeDBClusters and emits one data artifact per cluster.
CloudControl's readResource helper isn't usable for this — AWS::RDS::DBCluster has no CloudControl list operation — so the method needs a direct @aws-sdk/client-rds dependency.
Reuse the existing SDK default credential chain pattern from models/_lib/aws.ts; no new auth surface.

Related: the persisted state today is missing DBClusterMembers (filed separately). Fixing both together would make list results immediately useful for fleet operations.

Upstream repository: https://github.com/systeminit/swamp-extensions

Environment

Extension: @swamp/aws/rds@2026.05.06.1
swamp: 20260520.150010.0-sha.47868db6
OS: darwin (aarch64)
Deno: 2.7.14+19bd3d8
Shell: /bin/zsh

extension push: issue-verdict review is indistinguishable from missing/stale

Document model-method data-mutation surface (dataRepository.delete, findAllForModelSince, queryData)

@swamp/aws/cloudformation: expose StackSet instances, drift, and operations (Cloud Control cannot)

extension push: adversarial-review report hash is platform-dependent (macOS vs Linux), so committed reviews never match a cross-OS runner

model search --json returns a bare model object instead of {query, results} when exactly one model matches

model delete --json output shape doesn't match the documented {deleted, modelId, modelName, artifactsDeleted}

Extension API: allow export const extension to add resource specs, or document that it cannot

Add a way to list registered report definitions (report search only lists results)

workflow validate: method args with a Zod .default() are treated as required

extension quality scorer mis-detects quoted phrases in comments as bare imports

Support CI-friendly adversarial review artifacts for extension push

extension push --dry-run --json reports local helper imports as bogus model entries

Extension source: direct-content export scan only reads first 64 KiB, silently drops exports beyond it

Managed skills ship with dangling reference-doc links

Add a list/discover method to dbcluster for enumerating clusters in a region

workflow-scope report's dataRepository.getContent returns null for data written in the same workflow run

dbcluster state schema is missing DBClusterMembers (writer/reader, instance class)

workflow direct-execution inputs.* persist as globalArguments on auto-definitions and freeze on first run

Workflow validation should resolve modelType for direct-execution steps

bucket-policy StateSchema.PolicyDocument declared z.string() but CloudControl returns it as a parsed object

bucket-policy GlobalArgsSchema requires Bucket and PolicyDocument, blocking workflow-YAML direct execution of get

Report execute throws are advisory: workflow marked succeeded, exit 0, AND report output is discarded

dataRepository.getContent rejects string type in production but docs and testing helper demonstrate strings

Relationships

#403 Add a list/discover method to dbcluster for enumerating clusters in a region

Environment

Shipped