Update merge instructions and setup workflow to utilize GitHub MCP tool for labeling PRs

Author: brunoborges

.github/prompts/agentic-merge-upstream.prompt.md

@@ -327,18 +327,18 @@ Run the finish script which updates `.lastmerge`, runs a final build, and pushes
 
 ### PR Handling: Coding Agent vs. Manual Workflow
 
-**If running as a Copilot coding agent** (triggered via GitHub issue assignment by the weekly sync workflow), a pull request has **already been created automatically** for you. Do NOT create a new one. Just push your commits to the current branch — the existing PR will be updated. Add the `upstream-sync` label to the existing PR:
+**If running as a Copilot coding agent** (triggered via GitHub issue assignment by the weekly sync workflow), a pull request has **already been created automatically** for you. Do NOT create a new one. Just push your commits to the current branch — the existing PR will be updated. Add the `upstream-sync` label to the existing PR using the GitHub MCP tool:
 
-```bash
-gh pr edit <PR_NUMBER> --add-label "upstream-sync"
+```
+mcp_github_add_issue_labels(owner: "copilot-community-sdk", repo: "copilot-sdk-java", issue_number: <PR_NUMBER>, labels: ["upstream-sync"])
 ```
 
 > **No-changes scenario (coding agent only):** If after analyzing the upstream diff there are no relevant changes to port to the Java SDK, close the auto-created pull request, then close the triggering issue as "not planned" with a comment explaining that no changes were applicable.
 
 **If running manually** (e.g., from VS Code via the reusable prompt), create the Pull Request using the GitHub MCP tool (`mcp_github_create_pull_request`). Use `owner: copilot-community-sdk`, `repo: copilot-sdk-java`, `head: $BRANCH_NAME`, `base: main`. Then add the label:
 
-```bash
-gh pr edit <PR_NUMBER> --add-label "upstream-sync"
+```
+mcp_github_add_issue_labels(owner: "copilot-community-sdk", repo: "copilot-sdk-java", issue_number: <PR_NUMBER>, labels: ["upstream-sync"])
 ```
 
 The PR body should include:
@@ -414,7 +414,7 @@ Before finishing:
 - [ ] `.lastmerge` file updated with new commit hash
 - [ ] Branch pushed to remote
 - [ ] **Pull Request finalized** (coding agent: push to existing PR; manual: create via `mcp_github_create_pull_request`)
-- [ ] **`upstream-sync` label added** to the PR via `gh pr edit --add-label "upstream-sync"`
+- [ ] **`upstream-sync` label added** to the PR via `mcp_github_add_issue_labels`
 - [ ] PR URL provided to user
 
 ---

.github/prompts/coding-agent-merge-instructions.md

@@ -10,9 +10,9 @@ Commit changes incrementally. Update .lastmerge when done.
 IMPORTANT: A pull request has already been created automatically for you — do NOT create a new
 one. Push your commits to the current branch, and the existing PR will be updated.
 
-Add the 'upstream-sync' label to the existing PR using:
+Add the 'upstream-sync' label to the existing PR using the GitHub MCP tool:
 
-    gh pr edit <PR_NUMBER> --add-label upstream-sync
+    mcp_github_add_issue_labels(owner: "copilot-community-sdk", repo: "copilot-sdk-java", issue_number: <PR_NUMBER>, labels: ["upstream-sync"])
 
 If after analyzing the upstream diff there are no relevant changes to port to the Java SDK,
 close the pull request that was automatically created for you, then close this issue as

.github/workflows/copilot-setup-steps.yml

@@ -32,3 +32,6 @@ jobs:
 
       - name: Download dependencies
         run: mvn dependency:go-offline -B
+
+      - name: Install Copilot CLI
+        id: setup-copilot