ci: Add agents Build and Plan to opencode on GitHub (#607)

Usage: type `/opencode:Plan` or `/opencode:Build` followed by a prompt.

Author: PierreQuinton

.github/workflows/opencode.yml

@@ -13,26 +13,56 @@ on:
 jobs:
   opencode:
     if: |
-      (github.event_name == 'issue_comment' && contains(github.event.comment.body, '/opencode')) ||
-      (github.event_name == 'pull_request_review_comment' && contains(github.event.comment.body, '/opencode')) ||
-      (github.event_name == 'pull_request_review' && contains(github.event.review.body, '/opencode')) ||
-      (github.event_name == 'issues' && contains(github.event.issue.body, '/opencode'))
+      (github.event_name == 'issue_comment' && contains(github.event.comment.body, '/opencode:')) ||
+      (github.event_name == 'pull_request_review_comment' && contains(github.event.comment.body, '/opencode:')) ||
+      (github.event_name == 'pull_request_review' && contains(github.event.review.body, '/opencode:')) ||
+      (github.event_name == 'issues' && contains(github.event.issue.body, '/opencode:'))
     runs-on: ubuntu-latest
     permissions:
       id-token: write
-      contents: read
-      pull-requests: read
-      issues: read
+      contents: write
+      pull-requests: write
+      issues: write
     steps:
       - name: Checkout repository
         uses: actions/checkout@v6
         with:
           fetch-depth: 1
           persist-credentials: false
 
+      - name: Extract agent name
+        id: agent
+        env:
+          COMMENT_BODY: ${{ github.event.comment.body || github.event.review.body || github.event.issue.body }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          AGENT=$(echo "$COMMENT_BODY" | grep -oP '/opencode:\K[A-Za-z]+' | head -1)
+          if [[ ! "$AGENT" =~ ^(Build|Plan)$ ]]; then
+            ERROR_MSG="Error: Invalid agent '$AGENT'. Must be Build or Plan"
+            echo "$ERROR_MSG"
+
+            # Post comment with error
+            if [ "${{ github.event_name }}" = "issues" ]; then
+              NUMBER=${{ github.event.issue.number }}
+            else
+              NUMBER=${{ github.event.issue.number || github.event.pull_request.number }}
+            fi
+
+            curl -s -X POST \
+              -H "Authorization: token $GITHUB_TOKEN" \
+              -H "Accept: application/vnd.github.v3+json" \
+              "https://api.github.com/repos/${{ github.repository }}/issues/$NUMBER/comments" \
+              -d "{\"body\": \"❌ $ERROR_MSG\"}"
+
+            exit 1
+          fi
+          echo "agent=$AGENT" >> $GITHUB_OUTPUT
+
       - name: Run opencode
         uses: anomalyco/opencode/github@latest
         env:
           OPENCODE_API_KEY: ${{ secrets.OPENCODE_API_KEY }}
+          OPENCODE_PERMISSION: '{"bash": "deny"}'
         with:
           model: opencode-go/glm-5
+          agent: ${{ steps.agent.outputs.agent }}