diff --git a/src/google/adk/auth/auth_tool.py b/src/google/adk/auth/auth_tool.py
index 820540ef12..cef9e3fe40 100644
--- a/src/google/adk/auth/auth_tool.py
+++ b/src/google/adk/auth/auth_tool.py
@@ -129,6 +129,7 @@ def get_credential_key(self):
       auth_credential.oauth2.refresh_token = None
       auth_credential.oauth2.expires_at = None
       auth_credential.oauth2.expires_in = None
+      auth_credential.oauth2.redirect_uri = None
     credential_name = (
         f"{auth_credential.auth_type.value}_{_stable_model_digest(auth_credential)}"
         if auth_credential
diff --git a/src/google/adk/tools/openapi_tool/openapi_spec_parser/tool_auth_handler.py b/src/google/adk/tools/openapi_tool/openapi_spec_parser/tool_auth_handler.py
index 0d78a5759b..e415b9ce24 100644
--- a/src/google/adk/tools/openapi_tool/openapi_spec_parser/tool_auth_handler.py
+++ b/src/google/adk/tools/openapi_tool/openapi_spec_parser/tool_auth_handler.py
@@ -70,6 +70,7 @@ def _get_legacy_credential_key(
       auth_credential.oauth2.refresh_token = None
       auth_credential.oauth2.expires_at = None
       auth_credential.oauth2.expires_in = None
+      auth_credential.oauth2.redirect_uri = None
     scheme_name = (
         f"{auth_scheme.type_.name}_{self._legacy_stable_digest(auth_scheme.model_dump_json())}"
         if auth_scheme
@@ -99,6 +100,7 @@ def get_credential_key(
       auth_credential.oauth2.refresh_token = None
       auth_credential.oauth2.expires_at = None
       auth_credential.oauth2.expires_in = None
+      auth_credential.oauth2.redirect_uri = None
     scheme_name = (
         f"{auth_scheme.type_.name}_{_stable_model_digest(auth_scheme)}"
         if auth_scheme
diff --git a/tests/unittests/auth/test_auth_config.py b/tests/unittests/auth/test_auth_config.py
index ab5f6b584c..a4cd1c27bf 100644
--- a/tests/unittests/auth/test_auth_config.py
+++ b/tests/unittests/auth/test_auth_config.py
@@ -176,3 +176,41 @@ def test_credential_key_with_custom_auth_scheme():
   key = custom_config.credential_key
   assert key.startswith("adk_mock_custom_type_")
   assert len(key) > len("adk_mock_custom_type_")
+
+
+def test_credential_key_is_stable_across_redirect_uri(oauth2_auth_scheme):
+  """AuthConfig.credential_key should be invariant under redirect_uri changes.
+
+  redirect_uri is deployment configuration (which callback URL the auth
+  server should redirect to), not part of the credential identity. Two
+  AuthConfig instances built from credentials that share the same client_id,
+  client_secret, and scopes but differ only in redirect_uri should produce
+  the same credential_key.
+  """
+  credential_local = AuthCredential(
+      auth_type=AuthCredentialTypes.OAUTH2,
+      oauth2=OAuth2Auth(
+          client_id="client",
+          client_secret="secret",
+          redirect_uri="http://localhost:8001/oauth2callback",
+      ),
+  )
+  credential_deployed = AuthCredential(
+      auth_type=AuthCredentialTypes.OAUTH2,
+      oauth2=OAuth2Auth(
+          client_id="client",
+          client_secret="secret",
+          redirect_uri="https://deployed.example.com/oauth2callback",
+      ),
+  )
+
+  config_local = AuthConfig(
+      auth_scheme=oauth2_auth_scheme,
+      raw_auth_credential=credential_local,
+  )
+  config_deployed = AuthConfig(
+      auth_scheme=oauth2_auth_scheme,
+      raw_auth_credential=credential_deployed,
+  )
+
+  assert config_local.credential_key == config_deployed.credential_key
diff --git a/tests/unittests/tools/openapi_tool/openapi_spec_parser/test_tool_auth_handler.py b/tests/unittests/tools/openapi_tool/openapi_spec_parser/test_tool_auth_handler.py
index d32fc132da..bd56195126 100644
--- a/tests/unittests/tools/openapi_tool/openapi_spec_parser/test_tool_auth_handler.py
+++ b/tests/unittests/tools/openapi_tool/openapi_spec_parser/test_tool_auth_handler.py
@@ -353,3 +353,65 @@ async def test_refreshed_credential_is_persisted_to_store(
   assert persisted is not None
   assert persisted.oauth2.access_token == 'new_access_token'
   assert persisted.oauth2.refresh_token == 'new_refresh_token'
+
+
+def test_credential_key_is_stable_across_redirect_uri():
+  """get_credential_key should be invariant under redirect_uri changes.
+
+  redirect_uri is deployment configuration (which callback URL the auth
+  server should redirect to), not part of the credential identity. Two
+  AuthCredential instances that share the same client_id, client_secret,
+  and scopes but differ only in redirect_uri should produce the same key.
+  """
+  scheme, _ = get_mock_openid_scheme_credential()
+  credential_local = AuthCredential(
+      auth_type=AuthCredentialTypes.OAUTH2,
+      oauth2=OAuth2Auth(
+          client_id='client',
+          client_secret='secret',
+          redirect_uri='http://localhost:8001/oauth2callback',
+      ),
+  )
+  credential_deployed = AuthCredential(
+      auth_type=AuthCredentialTypes.OAUTH2,
+      oauth2=OAuth2Auth(
+          client_id='client',
+          client_secret='secret',
+          redirect_uri='https://deployed.example.com/oauth2callback',
+      ),
+  )
+  store = ToolContextCredentialStore(tool_context=create_mock_tool_context())
+
+  assert store.get_credential_key(
+      scheme, credential_local
+  ) == store.get_credential_key(scheme, credential_deployed)
+
+
+def test_legacy_credential_key_is_stable_across_redirect_uri():
+  """_get_legacy_credential_key should be invariant under redirect_uri changes.
+
+  The same redirect_uri-strip behavior must apply to the legacy key path so
+  that already-stored credentials remain findable after the fix.
+  """
+  scheme, _ = get_mock_openid_scheme_credential()
+  credential_local = AuthCredential(
+      auth_type=AuthCredentialTypes.OAUTH2,
+      oauth2=OAuth2Auth(
+          client_id='client',
+          client_secret='secret',
+          redirect_uri='http://localhost:8001/oauth2callback',
+      ),
+  )
+  credential_deployed = AuthCredential(
+      auth_type=AuthCredentialTypes.OAUTH2,
+      oauth2=OAuth2Auth(
+          client_id='client',
+          client_secret='secret',
+          redirect_uri='https://deployed.example.com/oauth2callback',
+      ),
+  )
+  store = ToolContextCredentialStore(tool_context=create_mock_tool_context())
+
+  assert store._get_legacy_credential_key(
+      scheme, credential_local
+  ) == store._get_legacy_credential_key(scheme, credential_deployed)