feat: add Batch.SendParams with tags support

[cpenned]

Summary

The batch send API supports tags per email. This PR adds a dedicated Batch.SendParams type that reflects the batch API surface.

Changes

• Add _BatchSendParamsDefault TypedDict for batch email parameters
• Add Batch.SendParams with explicit documentation for tags
• Update Batch.send / Batch.send_async signatures to accept List[Batch.SendParams]
• Document scheduled_at on Emails.SendParams (was present in the TypedDict but missing from docs)
• Add a test verifying tags are serialized in the batch request payload
• Update batch examples and tests to use Batch.SendParams

  

---

Summary by cubic

Introduces a dedicated Batch.SendParams for batch sends with per-email tags, and clarifies that batch requests do not support attachments or scheduled_at. Updates method signatures, examples, and tests, and documents scheduled_at on Emails.SendParams.

• New Features

  • Added Batch.SendParams (tags only); documented that batch excludes attachments and scheduled_at; removed attachment references from batch docs; documented scheduled_at on Emails.SendParams.
  • Updated Batch.send/Batch.send_async to accept List[Batch.SendParams]; examples updated; tests added (including tags serialization).

• Migration

  • Replace List[resend.Emails.SendParams] with List[resend.Batch.SendParams] when calling Batch.send or Batch.send_async.

^{Written for commit 57f72b8. Summary will update on new commits.}

[cubic-dev-ai]

0 issues found across 2 files (changes from recent commits).

<sub>Auto-approved: Adds a new TypedDict subclass, updates type annotations, and adds a test. No runtime logic changes, just explicit typing and documentation.

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[cubic-dev-ai]

1 issue found across 3 files (changes from recent commits).

Prompt for AI agents (unresolved issues)

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.


<file name="resend/emails/_emails.py">

<violation number="1" location="resend/emails/_emails.py:137">
P2: The `_BatchSendParamsDefault` class duplicates ~10 fields with identical types and docstrings from `_SendParamsDefault`. If a common field like `to`, `html`, or `tags` ever changes its type signature or docstring, both classes need updating — a real maintenance trap.

Consider extracting a shared base (e.g., `_SendParamsCommon`) with the common fields so that `_SendParamsDefault` adds only `attachments` and `scheduled_at`, and `_BatchSendParamsDefault` inherits the rest without duplication.</violation>
</file>

<sub>Tip: Review your code locally with the cubic CLI to iterate faster.

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[cubic-dev-ai]

P2: The _BatchSendParamsDefault class duplicates ~10 fields with identical types and docstrings from _SendParamsDefault. If a common field like to, html, or tags ever changes its type signature or docstring, both classes need updating — a real maintenance trap.

Consider extracting a shared base (e.g., _SendParamsCommon) with the common fields so that _SendParamsDefault adds only attachments and scheduled_at, and _BatchSendParamsDefault inherits the rest without duplication.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At resend/emails/_emails.py, line 137:

<comment>The `_BatchSendParamsDefault` class duplicates ~10 fields with identical types and docstrings from `_SendParamsDefault`. If a common field like `to`, `html`, or `tags` ever changes its type signature or docstring, both classes need updating — a real maintenance trap.

Consider extracting a shared base (e.g., `_SendParamsCommon`) with the common fields so that `_SendParamsDefault` adds only `attachments` and `scheduled_at`, and `_BatchSendParamsDefault` inherits the rest without duplication.</comment>

<file context>
@@ -134,6 +134,49 @@ class _SendParamsDefault(_SendParamsFrom):
     """
 
 
+class _BatchSendParamsDefault(_SendParamsFrom):
+    to: Union[str, List[str]]
+    """
</file context>

Dismissed because Cubic found issues in a newer review.

[cubic-dev-ai]

0 issues found across 1 file (changes from recent commits).

<sub>Requires human review: Auto-approval blocked by 1 unresolved issue from previous reviews.

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