[Docs] Add PR checklist skill for coding agents (#57084)

Signed-off-by: Benjamin Chislett <bchislett@nvidia.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,20 +1,33 @@
 <!-- markdownlint-disable -->
-PLEASE FILL IN THE PR DESCRIPTION HERE ENSURING ALL CHECKLIST ITEMS (AT THE BOTTOM) HAVE BEEN CONSIDERED.
 
-## Purpose
+## Overview
 
-## Test Plan
+<!-- Summarize the change in 1-2 lines. Link relevant issues and PRs. -->
 
-## Test Result
+## Claims
+
+<!-- State the accomplishments in a few concrete bullets: speedups, feature support, bug fixes, etc. -->
+
+## Validation
+
+<!-- Show evidence that the claims are met by this change, and steps to reproduce validations. -->
+
+## Details
+
+<!-- Explain motivation, design decisions, root cause, tradeoffs, and limitations concisely. Link or collapse lengthy supporting material. -->
 
 ---
-<details>
-<summary> Essential Elements of an Effective PR Description Checklist </summary>
 
-- [ ] The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
-- [ ] The test plan, such as providing test command.
-- [ ] The test results, such as pasting the results comparison before and after, or e2e results
-- [ ] (Optional) The necessary documentation update, such as updating `supported_models.md` and `examples` for a new model.
+<details>
+<summary> Pull Request Checklist </summary>
+
+- [ ] I used vLLM's `/pr-checklist` skill. (Mandatory for agents, optional for humans).
+- [ ] AI assistance was used during the creation of this PR.
+
+- [ ] **Design Fit:** Minimizes impact on core components, reuses existing functionality, and justifies added complexity.
+- [ ] **Testing and Validation:** Validates the change and ensures any added tests are meaningful and reliable, with CI coverage or documented CI resource constraints and validation performed outside CI.
+- [ ] **Code Quality and Style:** Keeps code and comments clear and concise, and updates relevant documentation and examples.
+- [ ] **Pull Request Contents:** Includes a brief summary and relevant links, supports claims with evidence, explains root causes and implementation trade-offs, and follows the contributing guide.
 </details>
 
 **BEFORE SUBMITTING, PLEASE READ <https://docs.vllm.ai/en/latest/contributing>** (anything written below this line will be removed by GitHub Actions)