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-choice-validation.R b/tests/testthat/test-readline-choice-validation.R
new file mode 100644
index 00000000..9463316e
--- /dev/null
+++ b/tests/testthat/test-readline-choice-validation.R
@@ -0,0 +1,12 @@
+test_that("interactive yes/no prompts accept only their declared choices", {
+  source_text <- paste(deparse(body(aFIPC::autoFIPC)), collapse = "\n")
+
+  bounded_choice_pattern <- 'grepl("^[12]$", n)'
+  legacy_unbounded_pattern <- 'grepl("^[0-9]+$", n)'
+
+  expect_equal(
+    lengths(regmatches(source_text, gregexpr(bounded_choice_pattern, source_text, fixed = TRUE))),
+    3L
+  )
+  expect_false(grepl(legacy_unbounded_pattern, source_text, fixed = TRUE))
+})