diff --git a/.jules/sentinel.md b/.jules/sentinel.md
index a8207a48..02985d61 100644
--- a/.jules/sentinel.md
+++ b/.jules/sentinel.md
@@ -1,4 +1,4 @@
 ## 2024-07-12 - Fix missing parameter validations
 **Vulnerability:** Unvalidated inputs passed to `if()` statements can cause process crashes (`condition has length > 1`) or unexpected coercion vulnerabilities.
 **Learning:** In R, optional boolean parameters that default to `NULL` should be validated using explicit runtime type validation (e.g., `if (!is.null(flag) && (!is.logical(flag) || length(flag) != 1 || is.na(flag)))`).
-**Prevention:** Always implement explicit runtime type validation for optional boolean parameters.
+**Prevention:** Always implement explicit runtime type validation for optional boolean parameters.
\ No newline at end of file
diff --git a/R/aFIPC.R b/R/aFIPC.R
index 62546519..918e19b1 100644
--- a/R/aFIPC.R
+++ b/R/aFIPC.R
@@ -141,7 +141,7 @@ autoFIPC <-
       }
       for (attempt in seq_len(3)) {
         n <- readline(prompt = "Is it correct? (1: Yes 2: No) : ")
-        if (grepl("^[0-9]+$", n)) {
+        if (grepl("^[12]$", n)) {
           return(as.integer(n))
         }
       }
@@ -171,7 +171,7 @@ autoFIPC <-
               readline(
                 prompt = "Do you want to use default BILOG-MG priors for oldform Data? (1: Yes 2: No) : "
               )
-            if (grepl("^[0-9]+$", n)) {
+            if (grepl("^[12]$", n)) {
               return(as.integer(n))
             }
           }
@@ -390,7 +390,7 @@ autoFIPC <-
               readline(
                 prompt = "Do you want to use default BILOG-MG priors for newform Data? (1: Yes 2: No) : "
               )
-            if (grepl("^[0-9]+$", n)) {
+            if (grepl("^[12]$", n)) {
               return(as.integer(n))
             }
           }
diff --git a/tests/testthat/test-readline-validation.R b/tests/testthat/test-readline-validation.R
new file mode 100644
index 00000000..7cbea4a1
--- /dev/null
+++ b/tests/testthat/test-readline-validation.R
@@ -0,0 +1,46 @@
+make_interactive_auto_fipc <- function(responses) {
+  prompt_count <- 0L
+  subject <- autoFIPC
+  overrides <- new.env(parent = environment(subject))
+  overrides$interactive <- function() TRUE
+  overrides$readline <- function(prompt = "") {
+    prompt_count <<- prompt_count + 1L
+    responses[[prompt_count]]
+  }
+  environment(subject) <- overrides
+
+  list(
+    run = function() {
+      subject(
+        newformXData = matrix(c(0, 1), ncol = 1),
+        oldformYData = matrix(c(0, 1), ncol = 1),
+        newformCommonItemNames = "item1",
+        oldformCommonItemNames = "item1",
+        itemtype = "2PL"
+      )
+    },
+    prompt_count = function() prompt_count
+  )
+}
+
+test_that("autoFIPC rejects non-menu numeric input before integer coercion", {
+  harness <- make_interactive_auto_fipc(c("3", "99999999999999999999", "10"))
+
+  expect_error(
+    harness$run(),
+    "Too many invalid common item confirmation attempts",
+    fixed = TRUE
+  )
+  expect_equal(harness$prompt_count(), 3L)
+})
+
+test_that("autoFIPC accepts the exact menu choice 2", {
+  harness <- make_interactive_auto_fipc("2")
+
+  expect_error(
+    harness$run(),
+    "Please write down pairs correctly",
+    fixed = TRUE
+  )
+  expect_equal(harness$prompt_count(), 1L)
+})