• DynamoDB UpdateItem condition expression on missing item: ConditionExpression such as attribute_exists(...) now correctly evaluates against the existing stored item (or empty if missing) — was incorrectly evaluating against the in-progress mutation, causing ConditionalCheckFailedException to never fire on missing items
• DynamoDB key schema validation: GetItem, DeleteItem, UpdateItem, BatchWriteItem, BatchGetItem now validate that supplied key attributes match the table schema in name and type — returns ValidationException: The provided key element does not match the schema
• ESM visibility timeout: SQS → Lambda event source mapping now respects the queue's configured VisibilityTimeout instead of hardcoding 30 s — prevents retry storms and duplicate deliveries when Lambda fails
• Lambda stdout/stderr separation: handler logs now go to stderr, response payload to stdout — matches AWS Lambda runtime contract; fixes log pollution in response payloads
• Lambda timeout error: subprocess.TimeoutExpired path now captures and returns stdout/stderr in the error log instead of returning an empty string
• ECS _maybe_mark_stopped container status: calls container.reload() before checking status to get live state from Docker — was reading stale cached status
• ECS stoppedAt/stoppingAt timestamps: now stored as ISO 8601 strings matching AWS ECS API format — was storing Unix epoch float
• ECS cluster task count: _recount_cluster() now recomputes running/pending counts from all tasks instead of decrementing — prevents count drift on concurrent task terminations
• Step Functions service integrations: Task state now dispatches to real MiniStack services via arn:aws:states::: resource URIs — sqs:sendMessage, sns:publish, dynamodb:putItem, dynamodb:getItem, dynamodb:deleteItem, dynamodb:updateItem, ecs:runTask, ecs:runTask.sync — was returning input passthrough instead of invoking the service
• 392 integration tests — all passing, including against Docker image