diff --git a/mcp/checkout.ts b/mcp/checkout.ts
index 0d0f9b4..1b3eb48 100644
--- a/mcp/checkout.ts
+++ b/mcp/checkout.ts
@@ -545,6 +545,7 @@ export function CheckoutPrTool(ctx: ToolContext) {
         diffPath,
         totalLines: countLines({ content: formatResult.content }),
         toc: formatResult.toc,
+        previous: ctx.toolState.diffCoverage,
       });
       log.debug(
         `» diff coverage initialized: diffPath=${diffPath}, totalLines=${ctx.toolState.diffCoverage.totalLines}, tocEntries=${ctx.toolState.diffCoverage.tocEntries.length}`
diff --git a/utils/diffCoverage.test.ts b/utils/diffCoverage.test.ts
index dfa96db..c4877f0 100644
--- a/utils/diffCoverage.test.ts
+++ b/utils/diffCoverage.test.ts
@@ -98,6 +98,24 @@ describe("diff coverage line checker", () => {
     ]);
   });
 
+  it("carries forward coveragePreflightRan from a previous state across checkout refreshes", () => {
+    const previous = createDiffCoverageState({ diffPath, totalLines: 30, toc });
+    previous.coveragePreflightRan = true;
+    previous.coveredRanges = [{ startLine: 5, endLine: 10 }];
+
+    const next = createDiffCoverageState({ diffPath, totalLines: 50, toc, previous });
+
+    expect(next.coveragePreflightRan).toBe(true);
+    // coveredRanges are tied to the previous diff content and must not leak forward
+    expect(next.coveredRanges).toEqual([]);
+    expect(next.totalLines).toBe(50);
+  });
+
+  it("defaults coveragePreflightRan to false when no previous state is provided", () => {
+    const state = createDiffCoverageState({ diffPath, totalLines: 30, toc });
+    expect(state.coveragePreflightRan).toBe(false);
+  });
+
   it("computes per-file unread ranges from tracked reads", () => {
     const state = createDiffCoverageState({
       diffPath,
diff --git a/utils/diffCoverage.ts b/utils/diffCoverage.ts
index 125360d..2ced6d9 100644
--- a/utils/diffCoverage.ts
+++ b/utils/diffCoverage.ts
@@ -78,13 +78,17 @@ export function createDiffCoverageState(params: {
   diffPath: string;
   totalLines: number;
   toc: string;
+  previous?: DiffCoverageState | undefined;
 }): DiffCoverageState {
   return {
     diffPath: params.diffPath,
     totalLines: params.totalLines,
     tocEntries: parseDiffTocEntries({ toc: params.toc }),
     coveredRanges: [],
-    coveragePreflightRan: false,
+    // carry forward across checkout_pr refreshes so the nudge stays "once per
+    // review session". coveredRanges are intentionally not carried because
+    // line numbers are tied to the previous diff's content.
+    coveragePreflightRan: params.previous?.coveragePreflightRan ?? false,
   };
 }