[luyuzhe111]

TMax tasks that need port 8080 conflict with sandboxd listening on the same port. Use AgentCore's custom serving port configuration (protocolConfiguration.port) to route sandbox traffic to 11000, matching the task image's sandboxd listener. The prepared manifest carries this port into Runtime creation and updates.

Run deployment through uv run --script with boto3 1.43.123+ to support custom ports independently of the evaluation environment's aiobotocore constraints. Document custom-port configuration in the sandbox quickstart, correct the fixed-port guidance, and remove the resolved port conflicts from TMax's limitations.

Validation

• Live VPC validation of both ARM64 task images: Runtime creation, update, and reuse succeeded with sandboxd on 11000.
• Upstream reference solutions and original verifiers: mlflow-register passed 3/3 tests and token-auth-websocket passed 10/10 tests, both with reward 1. Task services used 8080, and sandboxd remained healthy after verification.
• Existing sandbox live suite: 5 passed with sandboxd on 11000.
• Deployment script's isolated environment: --help succeeded. Repository pre-commit checks and git diff --check passed.

[luyuzhe111]

cc @chenqihong