diff --git a/src/signals/local-branch.ts b/src/signals/local-branch.ts
index eb12febc68..dc7ca7dba6 100644
--- a/src/signals/local-branch.ts
+++ b/src/signals/local-branch.ts
@@ -19,6 +19,7 @@ import { buildRepoRewardRisk, type RepoRewardRisk, type RewardRiskAction } from
 import { buildLocalWorkspaceIntelligence, type LocalWorkspaceIntelligence } from "./local-workspace-intelligence";
 import { buildFocusManifestGuidance, parseFocusManifest, type FocusManifestGuidance } from "./focus-manifest";
 import { sanitizeLocalScorerWarnings } from "./local-scorer-diagnostics";
+import { isPublicSafeText } from "./redaction";
 import { deriveEligibilityPlan } from "../services/eligibility-plan";
 import { scenarioInputFromLocalBranchMetadata } from "../scenarios/input-model";
 import { renderPublicScenarioSummary, type PublicScenarioSummary, type ScenarioSummaryInput } from "../scenarios/scenario-summary";
@@ -1201,10 +1202,6 @@ function firstCommitTitle(messages: string[] | undefined): string | undefined {
   return messages?.find((message) => message.trim().length > 0)?.split("\n")[0]?.trim() || undefined;
 }
 
-function isPublicSafeText(text: string): boolean {
-  return !/\b(reward\w*|score\w*|wallet|hotkey|coldkey|mnemonic|farming|payout|ranking|raw[-_\s]?trust|trust[-_\s]?score|private[-_\s]?reviewability|reviewability)\b|\/Users\/|\/home\/|\/tmp\/|[A-Z]:[\\/]Users[\\/]/i.test(text);
-}
-
 function safeRepoPath(path: string): string {
   /* v8 ignore next -- Empty path fallback protects malformed local-git adapters; path redaction is covered by local branch tests. */
   return /^(\/Users\/|\/home\/|\/tmp\/|[A-Z]:\/Users\/)/i.test(String(path).replace(/\\/g, "/")) ? "[local path hidden]" : String(path || "(unknown path)").replace(/\\/g, "/");
diff --git a/src/signals/redaction.ts b/src/signals/redaction.ts
new file mode 100644
index 0000000000..c2b40c0f87
--- /dev/null
+++ b/src/signals/redaction.ts
@@ -0,0 +1,16 @@
+// #542: the canonical public/private boundary primitive. Any text destined for a PUBLIC surface — PR/issue
+// comments, check annotations, notifications, badge, extension payloads, slop/advisory reasons — must pass
+// `isPublicSafeText` first, so a single regex governs redaction and new surfaces cannot drift their own copy.
+//
+// It rejects gittensor economic/identity signals (rewards, raw/trust score, wallet/hotkey/coldkey/mnemonic,
+// farming, payout, ranking, (private) reviewability) and local filesystem paths.
+//
+// The pattern is intentionally NON-GLOBAL so `.test()` stays stateless (no `lastIndex` carry-over between
+// calls) and the exported constant can be reused safely across call sites and modules.
+export const PUBLIC_UNSAFE_PATTERN =
+  /\b(reward\w*|score\w*|wallet|hotkey|coldkey|mnemonic|farming|payout|ranking|raw[-_\s]?trust|trust[-_\s]?score|private[-_\s]?reviewability|reviewability)\b|\/Users\/|\/home\/|\/tmp\/|[A-Z]:[\\/]Users[\\/]/i;
+
+/** True iff `text` contains nothing that must stay private — i.e. it is safe to surface on a public GitHub surface. */
+export function isPublicSafeText(text: string): boolean {
+  return !PUBLIC_UNSAFE_PATTERN.test(text);
+}
diff --git a/test/unit/redaction.test.ts b/test/unit/redaction.test.ts
new file mode 100644
index 0000000000..6be22518b1
--- /dev/null
+++ b/test/unit/redaction.test.ts
@@ -0,0 +1,53 @@
+import { describe, expect, it } from "vitest";
+import { isPublicSafeText, PUBLIC_UNSAFE_PATTERN } from "../../src/signals/redaction";
+
+describe("isPublicSafeText (#542 shared public/private boundary)", () => {
+  it("accepts text with no private signals", () => {
+    expect(isPublicSafeText("Add a retry to the cache reconnect path.")).toBe(true);
+    expect(isPublicSafeText("- PR #12: changes requested.")).toBe(true);
+    expect(isPublicSafeText("")).toBe(true);
+  });
+
+  it("rejects gittensor economic / identity signals", () => {
+    for (const text of [
+      "estimated reward is high",
+      "your score will rise",
+      "wallet 5F...",
+      "hotkey leaked",
+      "coldkey backup",
+      "mnemonic phrase",
+      "this looks like farming",
+      "payout pending",
+      "ranking change",
+      "raw trust value",
+      "raw-trust score",
+      "trust_score 0.8",
+      "private reviewability internals",
+      "reviewability breakdown",
+    ]) {
+      expect(isPublicSafeText(text)).toBe(false);
+    }
+  });
+
+  it("rejects local filesystem paths (posix and Windows)", () => {
+    expect(isPublicSafeText("/Users/alice/project")).toBe(false);
+    expect(isPublicSafeText("/home/bob/repo")).toBe(false);
+    expect(isPublicSafeText("/tmp/scratch")).toBe(false);
+    expect(isPublicSafeText("C:\\Users\\carol\\repo")).toBe(false);
+    expect(isPublicSafeText("C:/Users/carol/repo")).toBe(false);
+  });
+
+  it("is case-insensitive", () => {
+    expect(isPublicSafeText("WALLET")).toBe(false);
+    expect(isPublicSafeText("Payout")).toBe(false);
+  });
+
+  it("uses a NON-global pattern so .test() is stateless (no lastIndex carry-over)", () => {
+    expect(PUBLIC_UNSAFE_PATTERN.global).toBe(false);
+    // A global regex would alternate true/false across repeated .test() calls on the same input.
+    expect(PUBLIC_UNSAFE_PATTERN.test("wallet")).toBe(true);
+    expect(PUBLIC_UNSAFE_PATTERN.test("wallet")).toBe(true);
+    expect(isPublicSafeText("clean line")).toBe(true);
+    expect(isPublicSafeText("clean line")).toBe(true);
+  });
+});