diff --git a/.github/sync-repo-settings.yaml b/.github/sync-repo-settings.yaml
index e64bb01e..cb51d59d 100644
--- a/.github/sync-repo-settings.yaml
+++ b/.github/sync-repo-settings.yaml
@@ -35,6 +35,7 @@ branchProtectionRules:
       - "langchain-python-sdk-pr-py311 (toolbox-testing-438616)"
       - "langchain-python-sdk-pr-py310 (toolbox-testing-438616)"
       - "langchain-python-sdk-pr-py39 (toolbox-testing-438616)"
+      - "core-python-sdk-pr-py313 (toolbox-testing-438616)"
     requiredApprovingReviewCount: 1
     requiresCodeOwnerReviews: true
     requiresStrictStatusChecks: true
@@ -42,4 +43,4 @@ branchProtectionRules:
 # Set team access
 permissionRules:
   - team: senseai-eco
-    permission: admin
\ No newline at end of file
+    permission: admin
diff --git a/.github/workflows/lint-toolbox-core.yaml b/.github/workflows/lint-toolbox-core.yaml
new file mode 100644
index 00000000..d9dd6ee6
--- /dev/null
+++ b/.github/workflows/lint-toolbox-core.yaml
@@ -0,0 +1,84 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+name: core
+on:
+  pull_request:
+    paths:
+      - 'packages/toolbox-core/**'
+      - '!packages/toolbox-core/**/*.md'
+  pull_request_target:
+    types: [labeled]
+
+# Declare default permissions as read only.
+permissions: read-all
+
+jobs:
+  lint:
+    if: "${{ github.event.action != 'labeled' || github.event.label.name == 'tests: run' }}"
+    name: lint
+    runs-on: ubuntu-latest
+    concurrency:
+      group: ${{ github.workflow }}-${{ github.ref }}
+      cancel-in-progress: true
+    defaults:
+      run:
+        working-directory: ./packages/toolbox-core
+    permissions:
+      contents: 'read'
+      issues: 'write'
+      pull-requests: 'write'
+    steps:
+      - name: Remove PR Label
+        if: "${{ github.event.action == 'labeled' && github.event.label.name == 'tests: run' }}"
+        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            try {
+              await github.rest.issues.removeLabel({
+                name: 'tests: run',
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                issue_number: context.payload.pull_request.number
+              });
+            } catch (e) {
+              console.log('Failed to remove label. Another job may have already removed it!');
+            }
+      - name: Checkout code
+        uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29 # v4.1.6
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
+          token: ${{ secrets.GITHUB_TOKEN }}
+      - name: Setup Python
+        uses: actions/setup-python@0b93645e9fea7318ecaed2b359559ac225c90a2b # v5.3.0
+        with:
+          python-version: "3.13"
+
+      - name: Install library requirements
+        run: pip install -r requirements.txt
+
+      - name: Install test requirements
+        run: pip install .[test]
+
+      - name: Run linters
+        run: |
+          black --check .
+          isort --check .
+
+      - name: Run type-check
+        env:
+          MYPYPATH: './src'
+        run: mypy --install-types --non-interactive --cache-dir=.mypy_cache/ -p toolbox_core
\ No newline at end of file
diff --git a/packages/toolbox-core/CHANGELOG.md b/packages/toolbox-core/CHANGELOG.md
new file mode 100644
index 00000000..e69de29b
diff --git a/packages/toolbox-core/DEVELOPER.md b/packages/toolbox-core/DEVELOPER.md
new file mode 100644
index 00000000..d8d43a18
--- /dev/null
+++ b/packages/toolbox-core/DEVELOPER.md
@@ -0,0 +1,38 @@
+# Development
+
+Below are the details to set up a development environment and run tests.
+
+## Install
+1. Clone the repository:
+   TODO: Correct repo URL
+    ```bash
+    git clone https://github.com/googleapis/genai-toolbox-langchain-python
+    ```
+1. Navigate to the package directory:
+    ```bash
+    cd genai-toolbox-langchain-python/packages/toolbox-core
+    ```
+1. Install the package in editable mode, so changes are reflected without
+   reinstall:
+    ```bash
+    pip install -e .
+    ```
+1. Make code changes and contribute to the SDK's development.
+> [!TIP]
+> Using `-e` option allows you to make changes to the SDK code and have
+> those changes reflected immediately without reinstalling the package.
+
+## Test
+1. Navigate to the package directory if needed:
+    ```bash
+    cd genai-toolbox-langchain-python/packages/toolbox-core
+    ```
+1. Install the SDK and test dependencies:
+    ```bash
+    pip install -e .[test]
+    ```
+1. Run tests and/or contribute to the SDK's development.
+
+    ```bash
+    pytest
+    ```
diff --git a/packages/toolbox-core/README.md b/packages/toolbox-core/README.md
new file mode 100644
index 00000000..a84b275a
--- /dev/null
+++ b/packages/toolbox-core/README.md
@@ -0,0 +1,2 @@
+# GenAI toolbox core
+# TODO: update readme
\ No newline at end of file
diff --git a/packages/toolbox-core/integration.cloudbuild.yaml b/packages/toolbox-core/integration.cloudbuild.yaml
new file mode 100644
index 00000000..66c1f4f9
--- /dev/null
+++ b/packages/toolbox-core/integration.cloudbuild.yaml
@@ -0,0 +1,46 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+steps:
+  - id: Install library requirements
+    name: 'python:${_VERSION}'
+    args:
+      - install
+      - '-r'
+      - 'packages/toolbox-core/requirements.txt'
+      - '--user'
+    entrypoint: pip
+  - id: Install test requirements
+    name: 'python:${_VERSION}'
+    args:
+      - install
+      - 'packages/toolbox-core[test]'
+      - '--user'
+    entrypoint: pip
+  - id: Run integration tests
+    name: 'python:${_VERSION}'
+    env:
+      - TOOLBOX_URL=$_TOOLBOX_URL
+      - TOOLBOX_VERSION=$_TOOLBOX_VERSION
+      - GOOGLE_CLOUD_PROJECT=$PROJECT_ID
+    args:
+      - '-c'
+      - >-
+        python -m pytest packages/toolbox-core/tests/
+    entrypoint: /bin/bash
+options:
+  logging: CLOUD_LOGGING_ONLY
+substitutions:
+  _VERSION: '3.13'
+  _TOOLBOX_VERSION: '0.2.1'
\ No newline at end of file
diff --git a/packages/toolbox-core/pyproject.toml b/packages/toolbox-core/pyproject.toml
new file mode 100644
index 00000000..980360ae
--- /dev/null
+++ b/packages/toolbox-core/pyproject.toml
@@ -0,0 +1,60 @@
+[project]
+name = "toolbox-core"
+dynamic = ["version"]
+readme = "README.md"
+description = "Python Base SDK for interacting with the Toolbox service"
+license = {file = "LICENSE"}
+requires-python = ">=3.9"
+authors = [
+    {name = "Google LLC", email = "googleapis-packages@google.com"}
+]
+
+# TODO: Add deps
+#dependencies = [
+#]
+
+classifiers = [
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: Apache Software License",
+    "Programming Language :: Python",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+]
+
+# Tells setuptools that packages are under the 'src' directory
+[tool.setuptools]
+package-dir = {"" = "src"}
+
+[tool.setuptools.dynamic]
+version = {attr = "toolbox_core.version.__version__"}
+
+[project.urls]
+Homepage = "https://github.com/googleapis/genai-toolbox-langchain-python/blob/main/packages/toolbox-core"
+Repository = "https://github.com/googleapis/genai-toolbox-langchain-python.git"
+"Bug Tracker" = "https://github.com/googleapis/genai-toolbox-langchain-python/issues"
+Changelog = "https://github.com/googleapis/genai-toolbox-langchain-python/blob/main/packages/toolbox-core/CHANGELOG.md"
+
+[project.optional-dependencies]
+test = [
+    "black[jupyter]==25.1.0",
+    "isort==6.0.1",
+    "mypy==1.15.0",
+    "pytest==8.3.5",
+]
+[build-system]
+requires = ["setuptools"]
+build-backend = "setuptools.build_meta"
+
+[tool.black]
+target-version = ['py39']
+
+[tool.isort]
+profile = "black"
+
+[tool.mypy]
+python_version = "3.9"
+warn_unused_configs = true
+disallow_incomplete_defs = true
diff --git a/packages/toolbox-core/requirements.txt b/packages/toolbox-core/requirements.txt
new file mode 100644
index 00000000..e69de29b
diff --git a/packages/toolbox-core/src/toolbox_core/__init__.py b/packages/toolbox-core/src/toolbox_core/__init__.py
new file mode 100644
index 00000000..433463de
--- /dev/null
+++ b/packages/toolbox-core/src/toolbox_core/__init__.py
@@ -0,0 +1,17 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from .client import DummyClass
+
+__all__ = ["DummyClass"]
diff --git a/packages/toolbox-core/src/toolbox_core/client.py b/packages/toolbox-core/src/toolbox_core/client.py
new file mode 100644
index 00000000..3caf79e1
--- /dev/null
+++ b/packages/toolbox-core/src/toolbox_core/client.py
@@ -0,0 +1,18 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+class DummyClass:
+    def __init__(self):
+        self.val = "dummy value"
diff --git a/packages/toolbox-core/src/toolbox_core/py.typed b/packages/toolbox-core/src/toolbox_core/py.typed
new file mode 100644
index 00000000..e69de29b
diff --git a/packages/toolbox-core/src/toolbox_core/version.py b/packages/toolbox-core/src/toolbox_core/version.py
new file mode 100644
index 00000000..702896da
--- /dev/null
+++ b/packages/toolbox-core/src/toolbox_core/version.py
@@ -0,0 +1,15 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+__version__ = "0.1.0"
diff --git a/packages/toolbox-core/tests/test_core.py b/packages/toolbox-core/tests/test_core.py
new file mode 100644
index 00000000..76ce659f
--- /dev/null
+++ b/packages/toolbox-core/tests/test_core.py
@@ -0,0 +1,20 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from toolbox_core import DummyClass
+
+
+class TestToolboxCore:
+    def test_dummy(self):
+        dummy_variable = DummyClass()
+        assert dummy_variable.val == "dummy value"