# AWS cross-region Private Endpoint knowledge

<!-- auto-oncall-optimization-record
{
  "schemaVersion": "auto-oncall-optimization-record-v1",
  "optimizationId": "aws-cross-region-private-endpoint-2026-08-26",
  "problems": [
    {
      "problemId": "aws-starter-essential-cross-region-private-endpoint-knowledge-missing",
      "summary": "The product-knowledge catalog omitted the documented TiDB Cloud Starter and Essential restriction against cross-region AWS Private Endpoint connections.",
      "status": "optimized_verified",
      "applicability": "TiDB Cloud Starter or Essential on AWS when the interface endpoint and TiDB Cloud endpoint service are in different AWS Regions; excludes Dedicated and same-region connections.",
      "issueKeys": ["ST-2914"],
      "sourceRefs": ["https://tidb.atlassian.net/browse/ST-2914#problem:aws-cross-region-private-endpoint-knowledge"],
      "signalTextIncludesAny": ["AWS PrivateLink", "cross-region", "eu-central-1", "ap-east-1"],
      "observedThrough": "2026-08-26",
      "effectiveAt": "2026-08-26T09:08:19Z",
      "verifiedAt": "2026-08-26T09:19:44Z",
      "attemptedAction": "Add an applicability-bounded repository topic and deterministic recall/content regression coverage for the official Starter and Essential cross-region restriction.",
      "evidenceUrl": "https://tidb.atlassian.net/rest/api/3/issue/7974516/comment/23700137"
    }
  ]
}
-->

- Optimization ID: `aws-cross-region-private-endpoint-2026-08-26`
- Owner: auto-oncall-services product-knowledge catalog and workspace materialization
- Source reference: ST-2914 single-ticket finding `st-2914-aws-cross-region-private-endpoint-knowledge`
- Implementation status: merged in aisupport PR #1106 and effective in staging
- Effective status: `optimized_verified`

## Bounded problem

The catalog had no topic for the official restriction that TiDB Cloud Starter
and Essential do not support cross-region AWS Private Endpoint connections. A
Router could therefore receive no repository-owned knowledge for this product
boundary and leave the capability question open for internal verification.

## Implemented change

Add one keyword-recalled topic that states the restriction and explicitly
excludes TiDB Cloud Dedicated and same-region connections. No Provider,
diagnostic, safety, customer-write, gate, or Final Response contract changes.

## Verification evidence

The focused regression test deterministically checks recall for AWS
PrivateLink between Frankfurt (`eu-central-1`) and Hong Kong (`ap-east-1`) and
checks the loaded topic's restriction and exclusion boundaries. The knowledge
change merged as `2f016d2e` in aisupport PR #1106. Current staging build
`9265fb2405ef734953e132ca1e7ddb8cf2fa09ed` contains that commit and was Ready
with zero restarts before verification.

The post-change `mode=write` replay completed as run
`1c05e016-f334-483a-b063-ef7bb76b3742` and DB run `150136`. It stated that AWS
TiDB Cloud Starter and Essential do not support cross-Region Private Endpoint
connections, rejected direct `ap-east-1` use of the `eu-central-1` service, and
provided a same-Region endpoint plus customer-controlled cross-Region private
network alternative. Evidence acquisition and response generation were both
complete, with no runner notice. Evaluation was `ai_better` with no AI gaps.

The write replay updated existing Jira internal comment `23700137` in place.
Direct Jira API readback confirmed the same comment ID, `public=false`, and the
expected corrected body. Database, Jira, evaluation, and Feishu Dashboard
publication all reported written or updated with no errors.

## Unresolved gaps

None for this bounded knowledge problem.

## Next validation action

Monitor later matching tickets and treat any newer reproduction as a regression
without suppressing unrelated ST-2914 problem signals.