feat: prompt for low review feedback coverage

Author: haasonsaas

TODO.md

@@ -93,7 +93,7 @@ This roadmap is derived from deep research into Greptile's public docs, blog, MC
 54. [ ] Add keyboard actions for thumbs, resolve, and jump-to-next-finding workflows.
 55. [x] Add file-level readiness summaries in the diff sidebar.
 56. [x] Add lifecycle-aware PR summaries that explain what still blocks merge.
-57. [ ] Add a "train the reviewer" callout when thumbs coverage on a review is low.
+57. [x] Add a "train the reviewer" callout when thumbs coverage on a review is low.
 58. [ ] Add review-change comparisons so users can diff one review run against the next on the same PR.
 59. [ ] Add better surfacing for incremental PR reviews so users know when only the delta was reviewed.
 60. [ ] Add discussion workflows that can convert repeated human comments into candidate rules or context snippets.
@@ -165,4 +165,5 @@ This roadmap is derived from deep research into Greptile's public docs, blog, MC
 - [x] Add a blocker-only review mode that narrows large reviews to open Error and Warning findings.
 - [x] Add file-level readiness summaries to the review diff sidebar.
 - [x] Add visible feedback badges on comments so accepted and rejected states are not icon-only.
+- [x] Add a train-the-reviewer callout on review detail when thumbs coverage is low.
 - [ ] Commit and push each validated checkpoint before moving to the next epic.

web/src/pages/ReviewView.tsx

@@ -13,6 +13,8 @@ import type { Comment, CommentLifecycleStatus, MergeReadiness, Severity, ReviewE
 type ViewMode = 'diff' | 'list'
 
 const BLOCKING_SEVERITIES = new Set<Severity>(['Error', 'Warning'])
+const LOW_FEEDBACK_COVERAGE_THRESHOLD = 0.5
+const MIN_FEEDBACK_COVERAGE_FINDINGS = 3
 
 type ReviewCommentFilters = {
   severityFilter: Set<Severity>
@@ -212,6 +214,11 @@ export function ReviewView() {
 
   const openErrorCount = review.summary?.open_by_severity.Error ?? 0
   const openWarningCount = review.summary?.open_by_severity.Warning ?? 0
+  const labeledFeedbackCount = comments.filter((comment) => comment.feedback === 'accept' || comment.feedback === 'reject').length
+  const feedbackCoverage = comments.length > 0 ? labeledFeedbackCount / comments.length : 1
+  const feedbackCoveragePercent = Math.round(feedbackCoverage * 100)
+  const shouldShowFeedbackCallout = comments.length >= MIN_FEEDBACK_COVERAGE_FINDINGS
+    && feedbackCoverage < LOW_FEEDBACK_COVERAGE_THRESHOLD
 
   return (
     <div className="flex h-full">
@@ -352,6 +359,30 @@ export function ReviewView() {
           </div>
         )}
 
+        {shouldShowFeedbackCallout && (
+          <div className="px-3 py-3 border-b border-accent/20 bg-accent/5">
+            <div className="flex items-start gap-3">
+              <div className="mt-0.5 w-7 h-7 rounded-full bg-accent/10 flex items-center justify-center shrink-0">
+                <MessageSquare size={14} className="text-accent" />
+              </div>
+              <div className="min-w-0 flex-1">
+                <div className="text-[10px] font-semibold text-accent tracking-[0.08em] font-code uppercase">
+                  Train the reviewer
+                </div>
+                <p className="mt-1 text-[12px] text-text-primary leading-relaxed">
+                  {labeledFeedbackCount === 0
+                    ? 'No thumbs recorded yet. Label findings below to train the reviewer.'
+                    : `You've labeled ${labeledFeedbackCount} of ${comments.length} findings. Add a few more thumbs so future reviews learn what to keep or suppress.`}
+                </p>
+              </div>
+              <div className="shrink-0 text-right">
+                <div className="text-[13px] font-semibold font-code text-accent">{feedbackCoveragePercent}%</div>
+                <div className="text-[10px] text-text-muted">coverage</div>
+              </div>
+            </div>
+          </div>
+        )}
+
         {/* Toolbar */}
         <div className="px-3 py-2 border-b border-border bg-surface flex items-center gap-2">
           {/* View mode toggle */}

web/src/pages/__tests__/ReviewView.test.tsx

@@ -175,4 +175,44 @@ describe('ReviewView blocker mode', () => {
 
     expect(screen.getByText('No open blockers remain in this review.')).toBeInTheDocument()
   })
+
+  it('shows a train-the-reviewer callout when thumbs coverage is low', () => {
+    useReviewMock.mockReturnValue({ data: makeReview(), isLoading: false })
+
+    render(<ReviewView />)
+
+    expect(screen.getByText('Train the reviewer')).toBeInTheDocument()
+    expect(screen.getByText('No thumbs recorded yet. Label findings below to train the reviewer.')).toBeInTheDocument()
+    expect(screen.getByText('0%')).toBeInTheDocument()
+  })
+
+  it('hides the train-the-reviewer callout when enough findings are labeled', () => {
+    useReviewMock.mockReturnValue({
+      data: makeReview({
+        comments: [
+          makeComment({ feedback: 'accept' }),
+          makeComment({
+            id: 'comment-2',
+            file_path: 'src/b.ts',
+            content: 'Informational note',
+            severity: 'Info',
+            category: 'Style',
+            feedback: 'reject',
+          }),
+          makeComment({
+            id: 'comment-3',
+            file_path: 'src/b.ts',
+            content: 'Resolved blocker',
+            severity: 'Warning',
+            status: 'Resolved',
+          }),
+        ],
+      }),
+      isLoading: false,
+    })
+
+    render(<ReviewView />)
+
+    expect(screen.queryByText('Train the reviewer')).not.toBeInTheDocument()
+  })
 })