diff --git a/src/db/retention.ts b/src/db/retention.ts
index 399b28102b..4a03ce59d6 100644
--- a/src/db/retention.ts
+++ b/src/db/retention.ts
@@ -104,6 +104,17 @@ export const LATEST_ONLY_SIGNAL_SNAPSHOT_TYPES = [
   "repo-doc-refresh-attempt",
   "repo-focus-manifest",
   "repo-public-focus-manifest",
+  // 2026-07-23 recurrence of #3810, new offenders: the contributor-intelligence writers (processors.ts's
+  // scoring pass) append one ~36KB row PER CONTRIBUTOR PER PASS for these three types — ~6GB in three
+  // weeks at current review volume, refilling D1's 10GB cap before the 90-day age window could ever
+  // engage. No reader consumes them as a series (the canonical latest lives in the dedicated
+  // contributor_evidence / contributor_scoring_profiles upsert tables; nothing calls
+  // listSignalSnapshots for contributor-* types), so latest-only is lossless for every actual consumer.
+  // contributor-decision-pack stays EXCLUDED: the retention doc above records it as a bounded
+  // trend/change series by design, and its volume is a fraction of these three.
+  "contributor-evidence-graph",
+  "contributor-outcome-history",
+  "contributor-strategy",
 ] as const;
 
 /**
diff --git a/test/unit/retention.test.ts b/test/unit/retention.test.ts
index ef1ec2e49f..0d8f9d4dc7 100644
--- a/test/unit/retention.test.ts
+++ b/test/unit/retention.test.ts
@@ -162,6 +162,32 @@ describe("dedupeSignalSnapshots", () => {
     expect(remaining?.id).toBe("s-3");
   });
 
+  it("dedupes the contributor-intelligence types to latest-per-contributor (2026-07 recurrence of #3810: ~6GB in three weeks)", async () => {
+    const env = createTestEnv();
+    for (const signalType of ["contributor-evidence-graph", "contributor-outcome-history", "contributor-strategy"] as const) {
+      await insertSignalSnapshot(env, `${signalType}-old`, signalType, "octocat", "2026-07-01T00:00:00.000Z");
+      await insertSignalSnapshot(env, `${signalType}-new`, signalType, "octocat", "2026-07-02T00:00:00.000Z");
+      await insertSignalSnapshot(env, `${signalType}-other`, signalType, "hubot", "2026-07-02T00:00:00.000Z");
+    }
+    // decision-pack is a bounded trend series by design — must remain untouched.
+    await insertSignalSnapshot(env, "pack-1", "contributor-decision-pack", "octocat", "2026-07-01T00:00:00.000Z");
+    await insertSignalSnapshot(env, "pack-2", "contributor-decision-pack", "octocat", "2026-07-02T00:00:00.000Z");
+
+    const results = await dedupeSignalSnapshots(env);
+    const byType = Object.fromEntries(results.map((r) => [r.signalType, r.deleted]));
+    expect(byType["contributor-evidence-graph"]).toBe(1);
+    expect(byType["contributor-outcome-history"]).toBe(1);
+    expect(byType["contributor-strategy"]).toBe(1);
+
+    const remaining = await env.DB.prepare("SELECT id FROM signal_snapshots ORDER BY id").all<{ id: string }>();
+    const ids = (remaining.results ?? []).map((row) => row.id);
+    expect(ids).toContain("contributor-strategy-new");
+    expect(ids).toContain("contributor-strategy-other");
+    expect(ids).not.toContain("contributor-strategy-old");
+    expect(ids).toContain("pack-1"); // series preserved
+    expect(ids).toContain("pack-2");
+  });
+
   it("dedupes private and public focus-manifest cache snapshots (regression for storage exhaustion)", async () => {
     const env = createTestEnv();
     await insertSignalSnapshot(env, "private-old", REPO_FOCUS_MANIFEST_SIGNAL, "JSONbored/loopover", "2026-06-01T00:00:00.000Z");
diff --git a/test/unit/selfhost-d1-size-probe.test.ts b/test/unit/selfhost-d1-size-probe.test.ts
index a978b0f928..f8f2813f4a 100644
--- a/test/unit/selfhost-d1-size-probe.test.ts
+++ b/test/unit/selfhost-d1-size-probe.test.ts
@@ -170,7 +170,10 @@ describe("fetchD1TableRowCount", () => {
       calls.push({ url: requestUrl(input), method: init?.method ?? "GET" });
       const body = JSON.parse(String(init?.body ?? "{}")) as { sql: string; params: string[] };
       capturedParams = body.params;
-      expect(body.sql).toContain("signal_type IN (?1, ?2, ?3, ?4)");
+      // Derived from the list itself so growing LATEST_ONLY_SIGNAL_SNAPSHOT_TYPES (as the #3810
+      // recurrences keep doing) can never silently desync this pin from the probe's real SQL.
+      const expectedPlaceholders = LATEST_ONLY_SIGNAL_SNAPSHOT_TYPES.map((_, index) => `?${index + 1}`).join(", ");
+      expect(body.sql).toContain(`signal_type IN (${expectedPlaceholders})`);
       return new Response(envelope([{ results: [{ total: 20225, dedup_total: 107, dedup_distinct_keys: 36 }], success: true, meta: {} }]));
     };
     const row = await fetchD1TableRowCount(config, "signal_snapshots", fetchImpl);