**26 issues found** across 50 files Confidence score: **3/5** - There is a concrete runtime risk in multiple async code paths (for example `resend/emails/_emails.py`, `resend/emails/_batch.py`, and `resend/domains/_domains.py`): when the async extra is not installed, `AsyncRequest` can be undefined and `_async` calls may fail with `NameError` instead of a clear guidance error. - Several new async examples (`examples/async/batch_email_send_async.py`, `examples/async/audiences_async.py`, `examples/async/contacts_async.py`, `examples/async/domains_async.py`) depend on specific API-key scopes, so production usage can fail with permission errors if keys are not provisioned correctly. - Given the medium-high severity and strong confidence on user-facing failure modes, this carries some regression risk, though fixes appear straightforward (explicit async dependency guards and clearer permission prerequisites). - Pay close attention to `resend/emails/_emails.py`, `resend/emails/_batch.py`, `resend/domains/_domains.py`, `resend/emails/_attachments.py`, `resend/topics/_topics.py`, `resend/contact_properties/_contact_properties.py` - async methods should fail gracefully with a clear ImportError when async support is missing.

Prompt for AI agents (unresolved issues)

```text Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately. P3: Use os.environ.get(...) (and optionally assign it) so missing RESEND_API_KEY triggers the intended error instead of a KeyError. P1: Custom agent: **API Key Permission Check SDK Methods** The new async batch send example uses Resend’s Batch.send_async. Confirm that production API keys have the required permissions for batch email sending before rollout to avoid permission failures. (Rule: API Key Permission Check SDK Methods) P2: Use os.environ.get(...) for the check so missing variables raise the intended EnvironmentError instead of a KeyError. P1: Custom agent: **API Key Permission Check SDK Methods** Add a reminder that API keys must have segment management permissions for these new async operations to avoid permission failures. P1: Custom agent: **API Key Permission Check SDK Methods** Confirm that the production API keys have the required Contacts/Audiences permissions for these new async operations to avoid permission-related failures after deployment. P1: Custom agent: **API Key Permission Check SDK Methods** These newly added async domain-management calls introduce new provider SDK operations; confirm production API keys have the required domain-management permissions to avoid permission failures after deployment (Rule: API Key Permission Check SDK Methods). P3: Use `os.environ.get` (or `os.getenv`) so the missing API key triggers the intended EnvironmentError instead of a KeyError. P2: Guard async methods when `resend[async]` is missing so they raise a clear ImportError instead of `NameError`. P2: If the async extra isn’t installed, `AsyncRequest` is undefined and calling this method raises a `NameError`. Add an explicit guard to raise a helpful ImportError when async support is missing. P2: Guard the async path when the optional AsyncRequest import is unavailable; otherwise send_async will crash with NameError when the async extra isn’t installed. P2: Guard async methods when the async extra isn’t installed; otherwise calling create_async/get_async raises NameError because AsyncRequest is undefined. P3: Use os.getenv (or os.environ.get) to avoid a KeyError when RESEND_API_KEY is missing so the intended EnvironmentError is raised. P2: Swallowing the ImportError leaves `AsyncRequest` undefined, so calling any async method without the async extra will crash with a `NameError`. Raise a clear error (or guard in the async methods) so missing extras fail predictably. P2: This test will pass even if `update_async` doesn’t raise because there’s no failure path when no exception occurs. Use `pytest.raises` to make the expectation explicit. P2: Guard the async methods when AsyncRequest isn’t available. Right now a missing async extra will surface as a NameError instead of a clear install error. P2: Guard async methods with a clear ImportError when `AsyncRequest` isn't available; otherwise calling these methods without `resend[async]` raises a `NameError`. P2: Calling the async methods will raise `NameError` when the optional async dependency is not installed because `AsyncRequest` is never defined after the import `pass`. Add a guard or explicit error so users get a clear ImportError instead of a runtime NameError. P2: Use `os.environ.get` (or `os.getenv`) so missing keys trigger the intended `EnvironmentError` instead of a `KeyError`. P2: `AsyncRequest` can be undefined when the async extra isn’t installed, so calling this async method will raise `NameError`. Add an explicit guard/ImportError so users get a clear message when async support isn’t available. P2: Guard async methods when AsyncRequest isn’t available so callers get a clear ImportError instead of a NameError. P2: Swallowing the ImportError leaves `AsyncRequest` undefined, so any `_async` call crashes with a NameError/TypeError. Define a sentinel and raise a clear ImportError when async methods are used without the extra installed. P2: Guard async methods when AsyncRequest is unavailable to avoid a NameError and raise a clear ImportError for missing async extras. P2: Avoid direct os.environ indexing here; it throws KeyError when RESEND_API_KEY is unset, so your custom error is never raised. P2: Guard async calls with a clear ImportError when the async extra isn’t installed; otherwise calling list_async will raise NameError. P2: Guard async methods when AsyncRequest isn’t available. With the current silent ImportError pass, calling a *_async method without the async extra raises a NameError instead of a clear install hint. P2: Guard async methods when the async extra isn’t installed. As written, calling this method without `resend[async]` raises NameError because AsyncRequest isn’t defined. ```

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