chore: Add a pull request template

PiperOrigin-RevId: 822736669

Author: xuanyang15

.github/pull_request_template.md

@@ -0,0 +1,52 @@
+**Please ensure you have read the [contribution guide](https://github.com/google/adk-python/blob/main/CONTRIBUTING.md) before creating a pull request.**
+
+### Link to Issue or Description of Change
+
+**1. Link to an existing issue (if applicable):**
+
+- Closes: #_issue_number_
+- Related: #_issue_number_
+
+**2. Or, if no issue exists, describe the change:**
+
+_If applicable, please follow the issue templates to provide as much detail as
+possible._
+
+**Problem:**
+_A clear and concise description of what the problem is._
+
+**Solution:**
+_A clear and concise description of what you want to happen and why you choose
+this solution._
+
+### Testing Plan
+
+_Please describe the tests that you ran to verify your changes. This is required
+for all PRs that are not small documentation or typo fixes._
+
+**Unit Tests:**
+
+- [ ] I have added or updated unit tests for my change.
+- [ ] All unit tests pass locally.
+
+_Please include a summary of passed `pytest` results._
+
+**Manual End-to-End (E2E) Tests:**
+
+_Please provide instructions on how to manually test your changes, including any
+necessary setup or configuration. Please provide logs or screenshots to help
+reviewers better understand the fix._
+
+### Checklist
+
+- [ ] I have read the [CONTRIBUTING.md](https://github.com/google/adk-python/blob/main/CONTRIBUTING.md) document.
+- [ ] I have performed a self-review of my own code.
+- [ ] I have commented my code, particularly in hard-to-understand areas.
+- [ ] I have added tests that prove my fix is effective or that my feature works.
+- [ ] New and existing unit tests pass locally with my changes.
+- [ ] I have manually tested my changes end-to-end.
+- [ ] Any dependent changes have been merged and published in downstream modules.
+
+### Additional context
+
+_Add any other context or screenshots about the feature request here._

CONTRIBUTING.md

@@ -57,7 +57,9 @@ information on using pull requests.
 ### Requirement for PRs
 
 -   All PRs, other than small documentation or typo fixes, should have a Issue
-    associated. If not, please create one.
+    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.