diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 157f0355..559b4513 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.36.0"
+  ".": "0.36.1"
 }
\ No newline at end of file
diff --git a/.stats.yml b/.stats.yml
index 2523c283..150fc433 100644
--- a/.stats.yml
+++ b/.stats.yml
@@ -1,2 +1,2 @@
 configured_endpoints: 9
-openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/anthropic-aedee7570aa925baba404fc5bd3c8c1fffe8845517e492751db9b175c5cae9da.yml
+openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/anthropic-b629ddf1f1f1473462fc9bdb605abd5b7be51c3ba91c34750cd46e8404aec356.yml
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f1912caf..49da0564 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,19 @@
 # Changelog
 
+## 0.36.1 (2024-10-15)
+
+Full Changelog: [v0.36.0...v0.36.1](https://github.com/anthropics/anthropic-sdk-python/compare/v0.36.0...v0.36.1)
+
+### Bug Fixes
+
+* allow header params to override default headers ([#690](https://github.com/anthropics/anthropic-sdk-python/issues/690)) ([56f195f](https://github.com/anthropics/anthropic-sdk-python/commit/56f195ff1a67f2ba6e546ad897cbb0fe39f36a3b))
+* **beta:** merge betas param with the default value ([#695](https://github.com/anthropics/anthropic-sdk-python/issues/695)) ([f52eac9](https://github.com/anthropics/anthropic-sdk-python/commit/f52eac9357c0c496f1307def2628376d8a36e5ba))
+
+
+### Chores
+
+* **internal:** update spec URL ([#694](https://github.com/anthropics/anthropic-sdk-python/issues/694)) ([1b437cc](https://github.com/anthropics/anthropic-sdk-python/commit/1b437cc40f2e02e59df06744cc1458ee0cae202a))
+
 ## 0.36.0 (2024-10-08)
 
 Full Changelog: [v0.35.0...v0.36.0](https://github.com/anthropics/anthropic-sdk-python/compare/v0.35.0...v0.36.0)
diff --git a/pyproject.toml b/pyproject.toml
index 365529f1..d883c8a5 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "anthropic"
-version = "0.36.0"
+version = "0.36.1"
 description = "The official Python library for the anthropic API"
 dynamic = ["readme"]
 license = "MIT"
diff --git a/src/anthropic/_version.py b/src/anthropic/_version.py
index a96f7f1b..182c4e87 100644
--- a/src/anthropic/_version.py
+++ b/src/anthropic/_version.py
@@ -1,4 +1,4 @@
 # File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
 __title__ = "anthropic"
-__version__ = "0.36.0"  # x-release-please-version
+__version__ = "0.36.1"  # x-release-please-version
diff --git a/src/anthropic/resources/beta/messages/batches.py b/src/anthropic/resources/beta/messages/batches.py
index 6fed43b2..a6729ac1 100644
--- a/src/anthropic/resources/beta/messages/batches.py
+++ b/src/anthropic/resources/beta/messages/batches.py
@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 from typing import List, Iterable
+from itertools import chain
 
 import httpx
 
@@ -81,11 +82,17 @@ def create(
 
           timeout: Override the client-level default timeout for this request, in seconds
         """
-        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         extra_headers = {
-            **strip_not_given({"anthropic-beta": ",".join(str(e) for e in betas) if is_given(betas) else NOT_GIVEN}),
+            **strip_not_given(
+                {
+                    "anthropic-beta": ",".join(chain((str(e) for e in betas), ["message-batches-2024-09-24"]))
+                    if is_given(betas)
+                    else NOT_GIVEN
+                }
+            ),
             **(extra_headers or {}),
         }
+        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         return self._post(
             "/v1/messages/batches?beta=true",
             body=maybe_transform({"requests": requests}, batch_create_params.BatchCreateParams),
@@ -128,11 +135,17 @@ def retrieve(
         """
         if not message_batch_id:
             raise ValueError(f"Expected a non-empty value for `message_batch_id` but received {message_batch_id!r}")
-        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         extra_headers = {
-            **strip_not_given({"anthropic-beta": ",".join(str(e) for e in betas) if is_given(betas) else NOT_GIVEN}),
+            **strip_not_given(
+                {
+                    "anthropic-beta": ",".join(chain((str(e) for e in betas), ["message-batches-2024-09-24"]))
+                    if is_given(betas)
+                    else NOT_GIVEN
+                }
+            ),
             **(extra_headers or {}),
         }
+        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         return self._get(
             f"/v1/messages/batches/{message_batch_id}?beta=true",
             options=make_request_options(
@@ -179,11 +192,17 @@ def list(
 
           timeout: Override the client-level default timeout for this request, in seconds
         """
-        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         extra_headers = {
-            **strip_not_given({"anthropic-beta": ",".join(str(e) for e in betas) if is_given(betas) else NOT_GIVEN}),
+            **strip_not_given(
+                {
+                    "anthropic-beta": ",".join(chain((str(e) for e in betas), ["message-batches-2024-09-24"]))
+                    if is_given(betas)
+                    else NOT_GIVEN
+                }
+            ),
             **(extra_headers or {}),
         }
+        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         return self._get_api_list(
             "/v1/messages/batches?beta=true",
             page=SyncPage[BetaMessageBatch],
@@ -236,11 +255,17 @@ def cancel(
         """
         if not message_batch_id:
             raise ValueError(f"Expected a non-empty value for `message_batch_id` but received {message_batch_id!r}")
-        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         extra_headers = {
-            **strip_not_given({"anthropic-beta": ",".join(str(e) for e in betas) if is_given(betas) else NOT_GIVEN}),
+            **strip_not_given(
+                {
+                    "anthropic-beta": ",".join(chain((str(e) for e in betas), ["message-batches-2024-09-24"]))
+                    if is_given(betas)
+                    else NOT_GIVEN
+                }
+            ),
             **(extra_headers or {}),
         }
+        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         return self._post(
             f"/v1/messages/batches/{message_batch_id}/cancel?beta=true",
             options=make_request_options(
@@ -290,12 +315,18 @@ def results(
                 f"No `results_url` for the given batch; Has it finished processing? {batch.processing_status}"
             )
 
-        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         extra_headers = {"Accept": "application/binary", **(extra_headers or {})}
         extra_headers = {
-            **strip_not_given({"anthropic-beta": ",".join(str(e) for e in betas) if is_given(betas) else NOT_GIVEN}),
+            **strip_not_given(
+                {
+                    "anthropic-beta": ",".join(chain((str(e) for e in betas), ["message-batches-2024-09-24"]))
+                    if is_given(betas)
+                    else NOT_GIVEN
+                }
+            ),
             **(extra_headers or {}),
         }
+        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         return self._get(
             batch.results_url,
             options=make_request_options(
@@ -358,11 +389,17 @@ async def create(
 
           timeout: Override the client-level default timeout for this request, in seconds
         """
-        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         extra_headers = {
-            **strip_not_given({"anthropic-beta": ",".join(str(e) for e in betas) if is_given(betas) else NOT_GIVEN}),
+            **strip_not_given(
+                {
+                    "anthropic-beta": ",".join(chain((str(e) for e in betas), ["message-batches-2024-09-24"]))
+                    if is_given(betas)
+                    else NOT_GIVEN
+                }
+            ),
             **(extra_headers or {}),
         }
+        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         return await self._post(
             "/v1/messages/batches?beta=true",
             body=await async_maybe_transform({"requests": requests}, batch_create_params.BatchCreateParams),
@@ -405,11 +442,17 @@ async def retrieve(
         """
         if not message_batch_id:
             raise ValueError(f"Expected a non-empty value for `message_batch_id` but received {message_batch_id!r}")
-        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         extra_headers = {
-            **strip_not_given({"anthropic-beta": ",".join(str(e) for e in betas) if is_given(betas) else NOT_GIVEN}),
+            **strip_not_given(
+                {
+                    "anthropic-beta": ",".join(chain((str(e) for e in betas), ["message-batches-2024-09-24"]))
+                    if is_given(betas)
+                    else NOT_GIVEN
+                }
+            ),
             **(extra_headers or {}),
         }
+        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         return await self._get(
             f"/v1/messages/batches/{message_batch_id}?beta=true",
             options=make_request_options(
@@ -456,11 +499,17 @@ def list(
 
           timeout: Override the client-level default timeout for this request, in seconds
         """
-        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         extra_headers = {
-            **strip_not_given({"anthropic-beta": ",".join(str(e) for e in betas) if is_given(betas) else NOT_GIVEN}),
+            **strip_not_given(
+                {
+                    "anthropic-beta": ",".join(chain((str(e) for e in betas), ["message-batches-2024-09-24"]))
+                    if is_given(betas)
+                    else NOT_GIVEN
+                }
+            ),
             **(extra_headers or {}),
         }
+        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         return self._get_api_list(
             "/v1/messages/batches?beta=true",
             page=AsyncPage[BetaMessageBatch],
@@ -513,11 +562,17 @@ async def cancel(
         """
         if not message_batch_id:
             raise ValueError(f"Expected a non-empty value for `message_batch_id` but received {message_batch_id!r}")
-        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         extra_headers = {
-            **strip_not_given({"anthropic-beta": ",".join(str(e) for e in betas) if is_given(betas) else NOT_GIVEN}),
+            **strip_not_given(
+                {
+                    "anthropic-beta": ",".join(chain((str(e) for e in betas), ["message-batches-2024-09-24"]))
+                    if is_given(betas)
+                    else NOT_GIVEN
+                }
+            ),
             **(extra_headers or {}),
         }
+        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         return await self._post(
             f"/v1/messages/batches/{message_batch_id}/cancel?beta=true",
             options=make_request_options(
@@ -567,12 +622,18 @@ async def results(
                 f"No `results_url` for the given batch; Has it finished processing? {batch.processing_status}"
             )
 
-        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         extra_headers = {"Accept": "application/binary", **(extra_headers or {})}
         extra_headers = {
-            **strip_not_given({"anthropic-beta": ",".join(str(e) for e in betas) if is_given(betas) else NOT_GIVEN}),
+            **strip_not_given(
+                {
+                    "anthropic-beta": ",".join(chain((str(e) for e in betas), ["message-batches-2024-09-24"]))
+                    if is_given(betas)
+                    else NOT_GIVEN
+                }
+            ),
             **(extra_headers or {}),
         }
+        extra_headers = {"anthropic-beta": "message-batches-2024-09-24", **(extra_headers or {})}
         return await self._get(
             batch.results_url,
             options=make_request_options(
diff --git a/src/anthropic/resources/beta/prompt_caching/messages.py b/src/anthropic/resources/beta/prompt_caching/messages.py
index 3a7d8af4..7be54a3b 100644
--- a/src/anthropic/resources/beta/prompt_caching/messages.py
+++ b/src/anthropic/resources/beta/prompt_caching/messages.py
@@ -4,6 +4,7 @@
 
 from typing import List, Union, Iterable
 from functools import partial
+from itertools import chain
 from typing_extensions import Literal, overload
 
 import httpx
@@ -878,11 +879,17 @@ def create(
     ) -> PromptCachingBetaMessage | Stream[RawPromptCachingBetaMessageStreamEvent]:
         if not is_given(timeout) and self._client.timeout == DEFAULT_TIMEOUT:
             timeout = 600
-        extra_headers = {"anthropic-beta": "prompt-caching-2024-07-31", **(extra_headers or {})}
         extra_headers = {
-            **strip_not_given({"anthropic-beta": ",".join(str(e) for e in betas) if is_given(betas) else NOT_GIVEN}),
+            **strip_not_given(
+                {
+                    "anthropic-beta": ",".join(chain((str(e) for e in betas), ["prompt-caching-2024-07-31"]))
+                    if is_given(betas)
+                    else NOT_GIVEN
+                }
+            ),
             **(extra_headers or {}),
         }
+        extra_headers = {"anthropic-beta": "prompt-caching-2024-07-31", **(extra_headers or {})}
         return self._post(
             "/v1/messages?beta=prompt_caching",
             body=maybe_transform(
@@ -1808,11 +1815,17 @@ async def create(
     ) -> PromptCachingBetaMessage | AsyncStream[RawPromptCachingBetaMessageStreamEvent]:
         if not is_given(timeout) and self._client.timeout == DEFAULT_TIMEOUT:
             timeout = 600
-        extra_headers = {"anthropic-beta": "prompt-caching-2024-07-31", **(extra_headers or {})}
         extra_headers = {
-            **strip_not_given({"anthropic-beta": ",".join(str(e) for e in betas) if is_given(betas) else NOT_GIVEN}),
+            **strip_not_given(
+                {
+                    "anthropic-beta": ",".join(chain((str(e) for e in betas), ["prompt-caching-2024-07-31"]))
+                    if is_given(betas)
+                    else NOT_GIVEN
+                }
+            ),
             **(extra_headers or {}),
         }
+        extra_headers = {"anthropic-beta": "prompt-caching-2024-07-31", **(extra_headers or {})}
         return await self._post(
             "/v1/messages?beta=prompt_caching",
             body=await async_maybe_transform(