ci: Integrate Gemini API to generate changelog suggestions in PR checks.

.github/prompts/changelog.txt

@@ -0,0 +1,14 @@
+Generate a concise single-line changelog entry for this PR.
+
+Requirements:
+- Follow conventional commit format (feat/fix/docs/chore/refactor/etc)
+- Be specific about what changed
+- No markdown formatting or bullet points
+- Plain text only
+
+PR Title: {{PR_TITLE}}
+
+PR Description: {{PR_BODY}}
+
+Diff:
+{{DIFF}}

.github/workflows/pr-check.yml

@@ -72,13 +72,80 @@ jobs:
             echo "modified=false" >> $GITHUB_OUTPUT
           fi
 
+      - name: Generate changelog suggestion
+        if: steps.changelog-check.outputs.modified == 'false'
+        id: changelog-suggestion
+        env:
+          GEMINI_KEY: ${{ secrets.GEMINI_API_KEY }}
+          PR_TITLE: ${{ github.event.pull_request.title }}
+          PR_BODY: ${{ github.event.pull_request.body }}
+        run: |
+          # Get the full diff
+          git fetch origin ${{ github.base_ref }}
+          DIFF=$(git diff origin/${{ github.base_ref }}...HEAD)
+
+          echo "Diff size: ${#DIFF} characters"
+
+          # Limit diff size to avoid token limits (roughly 100k chars = ~25k tokens)
+          if [ ${#DIFF} -gt 100000 ]; then
+            echo "Diff too large, truncating to 100k characters"
+            DIFF="${DIFF:0:100000}"
+          fi
+
+          PROMPT=$(cat .github/prompts/changelog.txt)
+          PROMPT="${PROMPT//\{\{PR_TITLE\}\}/$PR_TITLE}"
+          PROMPT="${PROMPT//\{\{PR_BODY\}\}/$PR_BODY}"
+          PROMPT="${PROMPT//\{\{DIFF\}\}/$DIFF}"
+
+          PAYLOAD=$(jq -n \
+            --arg prompt "$PROMPT" \
+            '{
+              contents: [{
+                parts: [{
+                  text: $prompt
+                }]
+              }],
+              generationConfig: {
+                temperature: 0.3,
+                maxOutputTokens: 1000
+              }
+            }')
+
+          echo "Calling Gemini API..."
+          RESPONSE=$(curl -s -X POST \
+            "https://generativelanguage.googleapis.com/v1/models/gemini-2.5-flash:generateContent?key=$GEMINI_KEY" \
+            -H 'Content-Type: application/json' \
+            -d "$PAYLOAD")
+
+          echo "API Response:"
+          echo "$RESPONSE" | jq '.'
+
+          if echo "$RESPONSE" | jq -e '.error' > /dev/null; then
+            # Fallback to PR title if API fails
+            echo "API Error - using PR title as fallback"
+            echo "$RESPONSE" | jq '.error'
+            SUGGESTION="$PR_TITLE"
+          else
+            SUGGESTION=$(echo "$RESPONSE" | jq -r '.candidates[0].content.parts[0].text // ""' | tr -d '\n' | sed 's/^[[:space:]]*//;s/[[:space:]]*$//')
+            if [ -z "$SUGGESTION" ]; then
+              echo "Empty suggestion received, using PR title"
+              SUGGESTION="$PR_TITLE"
+            else
+              echo "Generated suggestion: $SUGGESTION"
+            fi
+          fi
+
+          echo "suggestion<<EOF" >> $GITHUB_OUTPUT
+          echo "$SUGGESTION" >> $GITHUB_OUTPUT
+          echo "EOF" >> $GITHUB_OUTPUT
+
       - name: Comment if changelog is missing
         if: steps.changelog-check.outputs.modified == 'false'
+        env:
+          CHANGELOG_ENTRY: ${{ steps.changelog-suggestion.outputs.suggestion }}
         uses: actions/github-script@v7
         with:
           script: |
-            const prTitle = context.payload.pull_request.title;
-
             // Check if bot already commented
             const { data: comments } = await github.rest.issues.listComments({
               owner: context.repo.owner,
@@ -99,11 +166,10 @@ jobs:
 
             **Recommendation:**
             \`\`\`
-            ${prTitle}
+            ${process.env.CHANGELOG_ENTRY}
             \`\`\`
 
             Please add an entry to the CHANGELOG.md or dismiss this if the change doesn't require documentation.
-
             **To dismiss:** Reply with \`/skip-changelog\` in any comment.`;
 
               await github.rest.issues.createComment({

CHANGELOG.md

@@ -7,6 +7,7 @@
     **New env vars:**\
        `stale_filter_ttl` duration in seconds before a stale filter is evicted from active filters cache\
        `enable_filters` enables or disables the filter RPC endpoints (default: true)
+- ci: Add Gemini API integration for changelog suggestions in PR checks
 
 ## v0.8.1 (2025-10-25)
 Fixes Testnet guest list for Light Client Prover.
@@ -50,7 +51,7 @@ Node operators need to rescan L1:
 # use citrea-cli v0.7.2
 citrea-cli --rollback --node-type fullnode --db-path path/to/db --l2-target 9999999999 --l1-target 74247 --sequencer-commitment-index 0
 
-citrea-cli clear-pending --db-path path/to/dbs 
+citrea-cli clear-pending --db-path path/to/dbs
 ```
 
 
@@ -63,7 +64,7 @@ Node operators need to rescan L1:
 # use citrea-cli v0.7.1
 citrea-cli --rollback --node-type fullnode --db-path path/to/db --l2-target 9999999999 --l1-target 74247 --sequencer-commitment-index 0
 
-citrea-cli clear-pending --db-path path/to/dbs 
+citrea-cli clear-pending --db-path path/to/dbs
 ```
 
 ## v0.7.0 (2025-04-18)