diff --git a/apps/server/src/secrets/SecretRequests.test.ts b/apps/server/src/secrets/SecretRequests.test.ts
index 026b9775b52d1..a8db8eb747127 100644
--- a/apps/server/src/secrets/SecretRequests.test.ts
+++ b/apps/server/src/secrets/SecretRequests.test.ts
@@ -341,7 +341,7 @@ it.effect("a ref only works in the project it was entered for", () =>
       const elsewhere = yield* service
         .consume({ ref, projectId: ProjectId.make("project-other") })
         .pipe(Effect.flip);
-      assert.include(elsewhere.message, "does not exist");
+      assert.equal(elsewhere.reason, "ref_wrong_project");
       assert.equal(yield* service.consume({ ref, projectId }), "ghp_secret");
     }),
   ),
diff --git a/apps/server/src/secrets/SecretRequests.ts b/apps/server/src/secrets/SecretRequests.ts
index cef9191bbf3dc..0105e107dd1c3 100644
--- a/apps/server/src/secrets/SecretRequests.ts
+++ b/apps/server/src/secrets/SecretRequests.ts
@@ -246,8 +246,10 @@ const make = Effect.gen(function* () {
     const decoded = Option.flatMap(stored, (bytes) =>
       decodeStored(new TextDecoder().decode(bytes)),
     );
-    if (Option.isNone(decoded) || decoded.value.projectId !== input.projectId) {
-      return yield* new SecretRequestError({ reason: "ref_unavailable" });
+    if (Option.isNone(decoded)) return yield* new SecretRequestError({ reason: "ref_unavailable" });
+    // Before the expiry check, so a caller from another project never deletes the value.
+    if (decoded.value.projectId !== input.projectId) {
+      return yield* new SecretRequestError({ reason: "ref_wrong_project" });
     }
     if ((yield* Clock.currentTimeMillis) - decoded.value.savedAt > SECRET_REF_TTL_MS) {
       yield* removeLogged(storeName(input.ref));
diff --git a/packages/contracts/src/secretRequest.ts b/packages/contracts/src/secretRequest.ts
index ccd114c397e38..deabfccd3b167 100644
--- a/packages/contracts/src/secretRequest.ts
+++ b/packages/contracts/src/secretRequest.ts
@@ -49,6 +49,8 @@ const SECRET_REQUEST_FAILURE_MESSAGES = {
   read_failed: "Could not read the secret.",
   ref_unavailable:
     "That secretRef was already used or does not exist. Ask the user again with request_secret.",
+  ref_wrong_project:
+    "That secretRef was entered in another project. Ask with request_secret from a thread in the project that uses it.",
   ref_expired: "That secretRef expired. Ask the user again with request_secret.",
   consume_failed: "Could not use that secretRef. Try again.",
   not_a_file_request: