feat: surface incremental PR review coverage

Author: haasonsaas

TODO.md

@@ -95,7 +95,7 @@ This roadmap is derived from deep research into Greptile's public docs, blog, MC
 56. [x] Add lifecycle-aware PR summaries that explain what still blocks merge.
 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.
+59. [x] 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.
 
 ## 7. Analytics, Reporting, and Quality Dashboards
@@ -169,4 +169,5 @@ This roadmap is derived from deep research into Greptile's public docs, blog, MC
 - [x] Add structured custom context and per-path instruction editors to the Settings review context workflow.
 - [x] Expose latest-review PR comment search with unresolved, resolved, and dismissed lifecycle filters through the API.
 - [x] Close TODO drift for existing comment lifecycle update APIs now that read and write surfaces are both shipped.
+- [x] Make PR readiness explicitly call out incremental review coverage when newer commits were not part of the latest pass.
 - [ ] Commit and push each validated checkpoint before moving to the next epic.

web/src/components/PrReadinessSummary.tsx

@@ -24,6 +24,11 @@ const READINESS_LABELS: Record<MergeReadiness, string> = {
 export function PrReadinessSummary({ readiness, isLoading = false, error, onOpenReview }: Props) {
   const latestReview = readiness?.latest_review
   const summary = latestReview?.summary
+  const isIncrementalReview = Boolean(
+    readiness?.current_head_sha
+    && latestReview?.reviewed_head_sha
+    && readiness.current_head_sha !== latestReview.reviewed_head_sha,
+  )
 
   return (
     <div className="mb-4 rounded-lg border border-border-subtle bg-surface p-3">
@@ -64,6 +69,17 @@ export function PrReadinessSummary({ readiness, isLoading = false, error, onOpen
         </div>
       ) : (
         <>
+          {isIncrementalReview && readiness?.current_head_sha && latestReview?.reviewed_head_sha && (
+            <div className="mb-3 rounded border border-accent/20 bg-accent/5 p-3">
+              <div className="text-[11px] font-medium text-accent mb-1">Incremental review coverage</div>
+              <div className="text-[11px] text-text-secondary">
+                DiffScope last reviewed PR head <span className="font-code text-text-primary">{shortSha(latestReview.reviewed_head_sha)}</span>,
+                but GitHub is now at <span className="font-code text-text-primary">{shortSha(readiness.current_head_sha)}</span>.
+                This readiness summary does not include the newer delta yet.
+              </div>
+            </div>
+          )}
+
           <div className="flex flex-wrap items-center gap-2 mb-3">
             <span className={`text-[10px] px-2 py-0.5 rounded font-code ${READINESS_STYLES[summary.merge_readiness]}`}>
               {READINESS_LABELS[summary.merge_readiness]}

web/src/components/__tests__/PrReadinessSummary.test.tsx

@@ -67,11 +67,19 @@ describe('PrReadinessSummary', () => {
     render(<PrReadinessSummary readiness={makeSnapshot()} />)
 
     expect(screen.getByText('Needs Attention')).toBeInTheDocument()
+    expect(screen.getByText('Incremental review coverage')).toBeInTheDocument()
+    expect(screen.getByText(/does not include the newer delta yet/i)).toBeInTheDocument()
     expect(screen.getByText('Open blockers')).toBeInTheDocument()
     expect(screen.getByText('2')).toBeInTheDocument()
     expect(screen.getByText('2 blocking findings remain open.')).toBeInTheDocument()
-    expect(screen.getByText('0123456789ab')).toBeInTheDocument()
-    expect(screen.getByText('fedcba987654')).toBeInTheDocument()
+    expect(screen.getAllByText('0123456789ab')).toHaveLength(2)
+    expect(screen.getAllByText('fedcba987654')).toHaveLength(2)
+  })
+
+  it('does not show the incremental callout when the latest review matches the current head', () => {
+    render(<PrReadinessSummary readiness={makeSnapshot({ current_head_sha: 'fedcba9876543210' })} />)
+
+    expect(screen.queryByText('Incremental review coverage')).not.toBeInTheDocument()
   })
 
   it('opens the latest review when requested', async () => {