feat(plugins): Add RateLimitPlugin for global request rate limiting

Add a new RateLimitPlugin that enforces global rate limiting across all
LLM models using a sliding window algorithm. The plugin blocks (waits)
when the rate limit is exceeded, ensuring requests are processed within
the configured limit.

Key features:
- Global rate limiting (default 15 QPM) across all models
- Sliding window algorithm for accurate tracking
- Automatic blocking when limit exceeded (no errors thrown)
- Thread-safe with asyncio locks
- Automatic cleanup of expired timestamps

Example usage:
```python
from google.adk.plugins import RateLimitPlugin

runner = Runner(
    agents=[agent],
    plugins=[RateLimitPlugin(max_requests_per_minute=15)]
)
```

.github/ISSUE_TEMPLATE/bug_report.md

@@ -19,7 +19,7 @@ Steps to reproduce the behavior:
 1. Install '...'
 2. Run '....'
 3. Open '....'
-4. Provide error or stacktrace
+4. Provie error or stacktrace
 
 **Expected behavior**
 A clear and concise description of what you expected to happen.

.github/workflows/analyze-releases-for-adk-docs-updates.yml

@@ -16,10 +16,10 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
       - name: Set up Python
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@v5
         with:
           python-version: '3.11'
 

.github/workflows/check-file-contents.yml

@@ -1,4 +1,4 @@
-# Copyright 2026 Google LLC
+# 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.
@@ -24,7 +24,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Code
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
         with:
           fetch-depth: 2
 
@@ -96,7 +96,7 @@ jobs:
             echo ""
 
             set +e
-            FILES_WITH_FORBIDDEN_IMPORT=$(grep -lE '^from.*\bcli\b.*import.*$' $CHANGED_FILES)
+            FILES_WITH_FORBIDDEN_IMPORT=$(grep -lE '^from.*cli.*import.*$' $CHANGED_FILES)
             GREP_EXIT_CODE=$?
             set -e
 

.github/workflows/copybara-pr-handler.yml

@@ -25,7 +25,7 @@ jobs:
 
     steps:
       - name: Check for Copybara commits and close PRs
-        uses: actions/github-script@v8
+        uses: actions/github-script@v7
         with:
           github-token: ${{ secrets.ADK_TRIAGE_AGENT }}
           script: |

.github/workflows/discussion_answering.yml

@@ -15,16 +15,16 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
       - name: Set up Python
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@v5
         with:
           python-version: '3.11'
 
       - name: Authenticate to Google Cloud
         id: auth
-        uses: 'google-github-actions/auth@v3'
+        uses: 'google-github-actions/auth@v2'
         with:
           credentials_json: '${{ secrets.ADK_GCP_SA_KEY }}'
 

.github/workflows/isort.yml

@@ -1,4 +1,4 @@
-# Copyright 2026 Google LLC
+# 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.
@@ -26,12 +26,12 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
         with:
           fetch-depth: 2
 
       - name: Set up Python
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@v5
         with:
           python-version: '3.x'
 

.github/workflows/pr-triage.yml

@@ -20,10 +20,10 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
       - name: Set up Python
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@v5
         with:
           python-version: '3.11'
 

.github/workflows/pyink.yml

@@ -1,4 +1,4 @@
-# Copyright 2026 Google LLC
+# 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.
@@ -26,12 +26,12 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
         with:
           fetch-depth: 2
 
       - name: Set up Python
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@v5
         with:
           python-version: '3.x'
 

.github/workflows/python-unit-tests.yml

@@ -1,4 +1,4 @@
-# Copyright 2026 Google LLC
+# 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.
@@ -25,14 +25,14 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
 
     steps:
     - name: Checkout code
-      uses: actions/checkout@v6
+      uses: actions/checkout@v4
 
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v6
+      uses: actions/setup-python@v5
       with:
         python-version: ${{ matrix.python-version }}
 
@@ -48,6 +48,14 @@ jobs:
     - name: Run unit tests with pytest
       run: |
         source .venv/bin/activate
-        pytest tests/unittests \
-          --ignore=tests/unittests/artifacts/test_artifact_service.py \
-          --ignore=tests/unittests/tools/google_api_tool/test_googleapi_to_openapi_converter.py
+        if [[ "${{ matrix.python-version }}" == "3.9" ]]; then
+          pytest tests/unittests \
+            --ignore=tests/unittests/a2a \
+            --ignore=tests/unittests/tools/mcp_tool \
+            --ignore=tests/unittests/artifacts/test_artifact_service.py \
+            --ignore=tests/unittests/tools/google_api_tool/test_googleapi_to_openapi_converter.py
+        else
+          pytest tests/unittests \
+            --ignore=tests/unittests/artifacts/test_artifact_service.py \
+            --ignore=tests/unittests/tools/google_api_tool/test_googleapi_to_openapi_converter.py
+        fi

.github/workflows/stale-bot.yml

@@ -1,58 +0,0 @@
-# Copyright 2026 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: ADK Stale Issue Auditor
-
-on:
-  workflow_dispatch:
-
-  schedule:
-    # This runs at 6:00 AM UTC (10 PM PST)
-    - cron: '0 6 * * *'
-
-jobs:
-  audit-stale-issues:
-    if: github.repository == 'google/adk-python'
-    runs-on: ubuntu-latest
-    timeout-minutes: 60
-
-    permissions:
-      issues: write
-      contents: read
-
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v6
-
-      - name: Set up Python
-        uses: actions/setup-python@v6
-        with:
-          python-version: '3.11'
-
-      - name: Install dependencies
-        run: |
-          python -m pip install --upgrade pip
-          pip install requests google-adk
-
-      - name: Run Auditor Agent Script
-        env:
-          GITHUB_TOKEN: ${{ secrets.ADK_TRIAGE_AGENT }}
-          GOOGLE_API_KEY: ${{ secrets.GOOGLE_API_KEY }}
-          OWNER: ${{ github.repository_owner }}
-          REPO: adk-python
-          CONCURRENCY_LIMIT: 3
-          LLM_MODEL_NAME: "gemini-2.5-flash"
-          PYTHONPATH: contributing/samples
-
-        run: python -m adk_stale_agent.main

.github/workflows/triage.yml

@@ -2,34 +2,21 @@ name: ADK Issue Triaging Agent
 
 on:
   issues:
-    types: [opened, labeled]
-  schedule:
-    # Run every 6 hours to triage untriaged issues
-    - cron: '0 */6 * * *'
+    types: [opened, reopened]
 
 jobs:
   agent-triage-issues:
     runs-on: ubuntu-latest
-    # Run for:
-    # - Scheduled runs (batch processing)
-    # - New issues (need component labeling)
-    # - Issues labeled with "planned" (need owner assignment)
-    if: >-
-      github.repository == 'google/adk-python' && (
-        github.event_name == 'schedule' ||
-        github.event.action == 'opened' ||
-        github.event.label.name == 'planned'
-      )
     permissions:
       issues: write
       contents: read
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
       - name: Set up Python
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@v5
         with:
           python-version: '3.11'
 
@@ -43,8 +30,8 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.ADK_TRIAGE_AGENT }}
           GOOGLE_API_KEY: ${{ secrets.GOOGLE_API_KEY }}
           GOOGLE_GENAI_USE_VERTEXAI: 0
-          OWNER: ${{ github.repository_owner }}
-          REPO: ${{ github.event.repository.name }}
+          OWNER: 'google'
+          REPO: 'adk-python'
           INTERACTIVE: 0
           EVENT_NAME: ${{ github.event_name }} # 'issues', 'schedule', etc.
           ISSUE_NUMBER: ${{ github.event.issue.number }}

.github/workflows/upload-adk-docs-to-vertex-ai-search.yml

@@ -9,12 +9,11 @@ on:
 
 jobs:
   upload-adk-docs-to-vertex-ai-search:
-    if: github.repository == 'google/adk-python'
     runs-on: ubuntu-latest
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
       - name: Clone adk-docs repository
         run: git clone https://github.com/google/adk-docs.git /tmp/adk-docs
@@ -23,13 +22,13 @@ jobs:
         run: git clone https://github.com/google/adk-python.git /tmp/adk-python
 
       - name: Set up Python
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@v5
         with:
           python-version: '3.11'
 
       - name: Authenticate to Google Cloud
         id: auth
-        uses: 'google-github-actions/auth@v3'
+        uses: 'google-github-actions/auth@v2'
         with:
           credentials_json: '${{ secrets.ADK_GCP_SA_KEY }}'
 

.gitignore

@@ -101,7 +101,6 @@ Thumbs.db
 
 # AI Coding Tools - Project-specific configs
 # Developers should symlink or copy AGENTS.md and add their own overrides locally
-.adk/
 .claude/
 CLAUDE.md
 .cursor/

CONTRIBUTING.md

@@ -56,14 +56,14 @@ information on using pull requests.
 
 ### Requirement for PRs
 
--   All PRs, other than small documentation or typo fixes, should have an Issue
+-   All PRs, other than small documentation or typo fixes, should have a Issue
     associated. If a relevant issue doesn't exist, please create one first or
     you may instead describe the bug or feature directly within the PR
     description, following the structure of our issue templates.
 -   Small, focused PRs. Keep changes minimal—one concern per PR.
 -   For bug fixes or features, please provide logs or screenshot after the fix
     is applied to help reviewers better understand the fix.
--   Please include a `testing plan` section in your PR to describe how you
+-   Please include a `testing plan` section in your PR to talk about how you
     will test. This will save time for PR review. See `Testing Requirements`
     section for more details.
 
@@ -126,7 +126,7 @@ Depending on your change:
 
 For any changes that impact user-facing documentation (guides, API reference,
 tutorials), please open a PR in the
-[adk-docs](https://github.com/google/adk-docs) repository to update the relevant
+[adk-docs](https://github.com/google/adk-docs) repository to update relevant
 part before or alongside your code PR.
 
 ## Development Setup
@@ -145,7 +145,7 @@ part before or alongside your code PR.
 
 3.  **Create and activate a virtual environment:**
 
-    **NOTE**: ADK supports Python 3.10+. Python 3.11 and above is strongly
+    **NOTE**: ADK supports Python 3.9+. Python 3.11 and above is strongly
     recommended.
 
     Create a workspace venv using uv.
@@ -160,11 +160,7 @@ part before or alongside your code PR.
     source .venv/bin/activate
     ```
 
-    **Windows**
-
-    ```shell
-    source .\.venv\Scripts\activate
-    ```
+    **windows** `shell source .\.venv\Scripts\activate`
 
 4.  **Install dependencies:**
 
@@ -234,7 +230,7 @@ part before or alongside your code PR.
 ## Contributing Resources
 
 [Contributing folder](https://github.com/google/adk-python/tree/main/contributing)
-has resources that are helpful for contributors.
+has resources that is helpful for contributors.
 
 ## Vibe Coding
 

README.md

@@ -4,7 +4,7 @@
 [![PyPI](https://img.shields.io/pypi/v/google-adk)](https://pypi.org/project/google-adk/)
 [![Python Unit Tests](https://github.com/google/adk-python/actions/workflows/python-unit-tests.yml/badge.svg)](https://github.com/google/adk-python/actions/workflows/python-unit-tests.yml)
 [![r/agentdevelopmentkit](https://img.shields.io/badge/Reddit-r%2Fagentdevelopmentkit-FF4500?style=flat&logo=reddit&logoColor=white)](https://www.reddit.com/r/agentdevelopmentkit/)
-<a href="https://codewiki.google/github.com/google/adk-python"><img src="https://www.gstatic.com/_/boq-sdlc-agents-ui/_/r/Mvosg4klCA4.svg" alt="Ask Code Wiki" height="20"></a>
+[![Ask DeepWiki](https://deepwiki.com/badge.svg)](https://deepwiki.com/google/adk-python)
 
 <html>
     <h2 align="center">
@@ -17,8 +17,7 @@
       Important Links:
       <a href="https://google.github.io/adk-docs/">Docs</a>,
       <a href="https://github.com/google/adk-samples">Samples</a>,
-      <a href="https://github.com/google/adk-java">Java ADK</a>,
-      <a href="https://github.com/google/adk-go">Go ADK</a> &
+      <a href="https://github.com/google/adk-java">Java ADK</a> &
       <a href="https://github.com/google/adk-web">ADK Web</a>.
     </h3>
 </html>
@@ -33,7 +32,7 @@ deployment-agnostic, and compatible with other frameworks.
 
 ## 🔥 What's new
 
-- **Custom Service Registration**: Add a service registry to provide a generic way to register custom service implementations to be used in FastAPI server. See [short instruction](https://github.com/google/adk-python/discussions/3175#discussioncomment-14745120). ([391628f](https://github.com/google/adk-python/commit/391628fcdc7b950c6835f64ae3ccab197163c990))
+- **Custom Service Registration**: Add a service registry to provide a generic way to register custom service implementations to be used in FastAPI server. See short instruction [here](https://github.com/google/adk-python/discussions/3175#discussioncomment-14745120). ([391628f](https://github.com/google/adk-python/commit/391628fcdc7b950c6835f64ae3ccab197163c990))
 
 - **Rewind**: Add the ability to rewind a session to before a previous invocation ([9dce06f](https://github.com/google/adk-python/commit/9dce06f9b00259ec42241df4f6638955e783a9d1)).
 
@@ -158,13 +157,13 @@ We welcome contributions from the community! Whether it's bug reports, feature r
 
 ## Community Repo
 
-We have [adk-python-community repo](https://github.com/google/adk-python-community) that is home to a growing ecosystem of community-contributed tools, third-party
+We have [adk-python-community repo](https://github.com/google/adk-python-community)that is home to a growing ecosystem of community-contributed tools, third-party
 service integrations, and deployment scripts that extend the core capabilities
 of the ADK.
 
 ## Vibe Coding
 
-If you want to develop agent via vibe coding the [llms.txt](./llms.txt) and the [llms-full.txt](./llms-full.txt) can be used as context to LLM. While the former one is a summarized one and the later one has the full information in case your LLM has big enough context window.
+If you are to develop agent via vibe coding the [llms.txt](./llms.txt) and the [llms-full.txt](./llms-full.txt) can be used as context to LLM. While the former one is a summarized one and the later one has the full information in case your LLM has big enough context window.
 
 ## Community Events
 

autoformat.sh

@@ -1,5 +1,5 @@
 #!/bin/bash
-# Copyright 2026 Google LLC
+# 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.

contributing/README.md

@@ -1,6 +1,6 @@
 # Contributing Resources
 
-This folder hosts resources for ADK contributors, for example, testing samples etc.
+This folder host resources for ADK contributors, for example, testing samples etc.
 
 ## Samples
 
@@ -13,4 +13,4 @@ Samples folder host samples to test different features. The samples are usually
 The [adk_project_overview_and_architecture.md](adk_project_overview_and_architecture.md) describes the ADK project overview and its technical architecture from high-level.
 
 This is helpful for contributors to understand the project and design philosophy.
- It can also be fed into LLMs for vibe-coding.
+ It can also be feed into LLMs for vibe-coding.

contributing/adk_project_overview_and_architecture.md

@@ -34,7 +34,7 @@ my_adk_project/
     └── my_app/
         ├── agents/
         │   ├── my_agent/
-        │   │   ├── __init__.py   # Must contain: from . import agent \
+        │   │   ├── __init__.py   # Must contain: from. import agent \
         │   │   └── agent.py      # Must contain: root_agent = Agent(...) \
         │   └── another_agent/
         │       ├── __init__.py
@@ -43,7 +43,7 @@ my_adk_project/
 
 agent.py: Must define the agent and assign it to a variable named root_agent. This is how ADK's tools find it.
 
-`__init__.py`: In each agent directory, it must contain `from . import agent` to make the agent discoverable.
+`__init__.py`: In each agent directory, it must contain from. import agent to make the agent discoverable.
 
 ## Local Development & Debugging
 
@@ -69,7 +69,7 @@ We expose agents as production APIs using FastAPI.
 
 - Custom Endpoints: We can add our own routes (e.g., /health) to the app object returned by the helper.
 
-```Python
+Python
 
 from google.adk.cli.fast_api import get_fast_api_app
 app = get_fast_api_app(agent_dir="./agents")
@@ -77,7 +77,6 @@ app = get_fast_api_app(agent_dir="./agents")
 @app.get("/health")
 async def health_check():
     return {"status": "ok"}
-```
 
 
 ## Deployment to Production