docs: add pr-readiness Copilot skill (#4862)

Add a GitHub Copilot agent skill at .github/skills/pr-readiness/SKILL.md
that verifies PRs have a descriptive title, meaningful description, and
a properly formatted CHANGELOG entry under the current version.

Co-authored-by: Copilot <[email protected]>

Author: gcampbell-msft

.github/skills/pr-readiness/SKILL.md

@@ -0,0 +1,103 @@
+---
+name: pr-readiness
+description: >
+  Verify that a pull request into microsoft/vscode-cmake-tools meets contribution
+  requirements. Use when preparing, reviewing, or finalizing a PR to check for a
+  descriptive title, a meaningful description, and a properly formatted CHANGELOG entry.
+---
+
+# PR Readiness
+
+## PR Requirements Checklist
+
+### 1. PR Title
+
+The title must clearly and concisely describe the change from the user's perspective. It should:
+
+- Start with a verb (e.g., "Fix", "Add", "Improve", "Remove", "Update").
+- Mention the affected feature or area (e.g., presets, kits, CTest, build tasks, Project Outline).
+- Be specific enough that a reader understands the change without opening the PR.
+
+**Good examples:**
+
+- `Fix preset reloading loop when preset files are symlinks`
+- `Add "Delete Build Directory and Reconfigure" command`
+- `Improve CTest test ordering to match Test Explorer display`
+
+**Bad examples:**
+
+- `Fix bug` (too vague)
+- `Update code` (no useful information)
+- `WIP` (not ready for review)
+
+### 2. PR Description
+
+The PR body must include:
+
+- **What changed**: A short summary of the user-visible behavior change.
+- **Why**: The motivation — link to a GitHub issue if one exists (e.g., `Fixes #1234`).
+- **How** (if non-obvious): A brief explanation of the implementation approach when the change is complex.
+
+### 3. CHANGELOG Entry
+
+Every PR must add an entry to `CHANGELOG.md`.
+
+#### Where to insert
+
+Insert the entry under the **most recent (topmost) version heading** in `CHANGELOG.md`. The first version heading looks like `## <version>` (e.g., `## 1.23`). Always add the new entry at the **bottom** of the appropriate section (i.e., after all existing entries in that section).
+
+#### Which section
+
+Place the entry in exactly one of these three sections, creating the section if it does not already exist under the current version:
+
+| Section | Use when… |
+|---|---|
+| `Features:` | A new user-visible capability is added (new command, new setting, new UI element). |
+| `Improvements:` | An existing feature is enhanced, optimized, or has better UX — but no new capability is introduced. |
+| `Bug Fixes:` | A defect is corrected. |
+
+The sections appear in this fixed order: `Features:`, then `Improvements:`, then `Bug Fixes:`.
+
+#### Entry format
+
+Each entry follows this pattern:
+
+```
+- <Description>. [#<number>](<link>)
+```
+
+Where `<Description>` starts with a present-tense verb describing the user-visible change, and the link references either:
+
+- The **GitHub issue** it solves: `[#<issue number>](https://github.com/microsoft/vscode-cmake-tools/issues/<issue number>)`
+- Or the **PR** itself: `[#<pr number>](https://github.com/microsoft/vscode-cmake-tools/pull/<pr number>)`
+
+An entry may optionally credit an external contributor at the end: `[@user](https://github.com/user)`.
+
+**Examples:**
+
+```markdown
+Features:
+- Add "Delete Build Directory and Reconfigure" command that removes the entire build directory before reconfiguring, ensuring a completely clean state. [#4826](https://github.com/microsoft/vscode-cmake-tools/pull/4826)
+
+Improvements:
+- Run tests sequentially in alphabetical order (matching the Test Explorer display order) when `cmake.ctest.allowParallelJobs` is disabled. [#4829](https://github.com/microsoft/vscode-cmake-tools/issues/4829)
+
+Bug Fixes:
+- Fix `cmake.revealLog` set to `"focus"` not revealing the output panel or stealing focus. [#4471](https://github.com/microsoft/vscode-cmake-tools/issues/4471)
+- Fix garbled characters in the Output panel when MSVC outputs UTF-8 on non-UTF-8 Windows systems. [#4520](https://github.com/microsoft/vscode-cmake-tools/issues/4520) [@contributor](https://github.com/contributor)
+```
+
+#### What NOT to do
+
+- Do **not** add a new version heading — use the existing topmost one.
+- Do **not** place the entry under an older version.
+- Do **not** use past tense (write "Fix …", not "Fixed …").
+- Do **not** omit the issue or PR link.
+
+## Applying This Skill
+
+When reviewing or preparing a PR:
+
+1. **Check the title** — rewrite it if it is vague or missing context.
+2. **Check the description** — ensure it explains what, why, and (if needed) how.
+3. **Check `CHANGELOG.md`** — verify an entry exists under the current version in the correct section with the correct format. If missing, add one.

CHANGELOG.md

@@ -36,6 +36,7 @@ Improvements:
 - Append `cmake` to diagnostics that this extension contributes to the Problems Pane. [PR #4766](https://github.com/microsoft/vscode-cmake-tools/pull/4766)
 - Set the `VSCODE_CMAKE_TOOLS` environment variable for all spawned subprocesses so that `CMakeLists.txt` can detect when CMake is run from VS Code. [#4233](https://github.com/microsoft/vscode-cmake-tools/issues/4233)
 - Honor `debugger.workingDirectory` from the CMake File API when debugging a target, so that the `DEBUGGER_WORKING_DIRECTORY` target property is used as the debugger working directory. [#4595](https://github.com/microsoft/vscode-cmake-tools/issues/4595)
+- Add `pr-readiness` Copilot skill to verify PRs have a descriptive title, meaningful description, and a properly formatted CHANGELOG entry. [#4862](https://github.com/microsoft/vscode-cmake-tools/pull/4862)
 
 Bug Fixes:
 - Fix `tasks.json` schema validation rejecting valid CMake task commands `package` and `workflow`. [#4167](https://github.com/microsoft/vscode-cmake-tools/issues/4167)