ci: diff PRs with git instead of gh in review

.github/workflows/claude-review.yml

@@ -64,7 +64,14 @@ jobs:
           fetch-depth: 0
           submodules: recursive
 
+      - name: Resolve base branch
+        id: pr
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: echo "base=$(gh pr view ${{ github.event.issue.number }} --json baseRefName --jq .baseRefName)" >> "$GITHUB_OUTPUT"
+
       - uses: anthropics/claude-code-action@9ca9355b36297178e28d37c799d1c9c8a28e6507
+        id: claude
         with:
           claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
           prompt: |
@@ -75,12 +82,13 @@ jobs:
             ---
 
             Text after `/claude review` is an optional focus. Honor it but still report anything serious outside it.
-            The PR head is checked out. Use `gh pr view ${{ github.event.issue.number }}` and `gh pr diff ${{ github.event.issue.number }}`, read surrounding code as needed.
+            The PR head is checked out and the base branch is fetched as `origin/${{ steps.pr.outputs.base }}`. Use `gh pr view ${{ github.event.issue.number }}` for title and description.
+            Get the diff from git, never `gh pr diff` (GitHub refuses diffs over 20000 lines): `git diff --stat origin/${{ steps.pr.outputs.base }}...HEAD`, then `git diff origin/${{ steps.pr.outputs.base }}...HEAD -- <path>` per file or directory. Read surrounding code as needed. Split a large PR across Task agents by area.
 
             Steps:
             1. Read CONTRIBUTING.md.
             2. Read the PR title, description and diff.
-            3. Check existing comments so you don't repeat them: `gh api repos/${{ github.repository }}/pulls/${{ github.event.issue.number }}/comments` and `gh pr view ${{ github.event.issue.number }} --comments`. Skip findings already covered by a comment that still applies.
+            3. Check existing comments so you don't repeat them: `gh api --method GET repos/${{ github.repository }}/pulls/${{ github.event.issue.number }}/comments` and `gh pr view ${{ github.event.issue.number }} --comments`. Skip findings already covered by a comment that still applies.
             4. Verify each candidate finding against the code. Drop anything you can't confirm.
             5. Post one inline comment per confirmed finding with `mcp__github_inline_comment__create_inline_comment` (`confirmed: true`). Say what's wrong, why, and the fix. Add a committable suggestion only if it alone fully fixes the issue.
             6. Post one new summary comment with `gh pr comment ${{ github.event.issue.number }} --body ...`. Never edit earlier comments. Format:
@@ -104,9 +112,26 @@ jobs:
           claude_args: |
             --model claude-opus-5-5
             --max-turns 120
-            --allowedTools "Read,Grep,Glob,LS,Task,mcp__github_inline_comment__create_inline_comment,Bash(gh pr view:*),Bash(gh pr diff:*),Bash(gh pr comment:*),Bash(gh api repos/${{ github.repository }}/pulls/${{ github.event.issue.number }}/comments:*),Bash(git diff:*),Bash(git log:*),Bash(git show:*),Bash(git blame:*)"
+            --allowedTools "Read,Grep,Glob,LS,Task,mcp__github_inline_comment__create_inline_comment,Bash(gh pr view:*),Bash(gh pr comment:*),Bash(gh api --method GET repos/${{ github.repository }}/pulls/${{ github.event.issue.number }}/comments:*),Bash(git diff:*),Bash(git log:*),Bash(git show:*),Bash(git blame:*),Bash(git merge-base:*)"
             --disallowedTools "Edit,Write,MultiEdit,NotebookEdit,WebFetch,WebSearch"
 
+      - name: Upload transcript
+        if: always() && steps.claude.outputs.execution_file != ''
+        uses: actions/upload-artifact@v4
+        with:
+          name: claude-review-${{ github.event.issue.number }}-${{ github.run_id }}
+          path: ${{ steps.claude.outputs.execution_file }}
+          retention-days: 7
+          if-no-files-found: ignore
+
+      - name: Require a summary comment
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          SINCE: ${{ github.event.comment.created_at }}
+        run: |
+          gh api "repos/${{ github.repository }}/issues/${{ github.event.issue.number }}/comments?since=$SINCE&per_page=100" \
+            --jq '[.[] | select(.body | startswith("## Claude review"))] | length' | grep -qv '^0$'
+
       - if: failure()
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}