Name the setting that did not come through

The instructions mark exactly two steps REQUIRED, and the two markers
sucker looks for are those two steps. So a failure can say which one is
missing — the custom prompt, the persona, or both — instead of sending
someone back to re-read a page they have already followed.

Truncation causes the same symptom, so it is still named, but second:
it only applies once the settings really are set.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NX2SsmUqQftWTZAY4BDuFa

tests/errors.test.ts

@@ -10,16 +10,32 @@ import {
   NO_GREETING,
   SuckerError,
   TOO_FEW_MESSAGES,
-  TRUNCATED_CARD,
+  missingSetup,
   isImpossibleRequest,
   isSuckerError,
   userFacingMessage,
 } from "../src/lib/errors.ts";
 
-test("the one fixable failure is shown as written, with the advice that fixes it", () => {
-  assert.equal(userFacingMessage(TRUNCATED_CARD), TRUNCATED_CARD.message);
-  assert.match(TRUNCATED_CARD.message, /Context Size/);
-  assert.ok(TRUNCATED_CARD.message.includes(CONTACT));
+test("a missing setting is named, not left to the reader to find", () => {
+  const noPrompt = missingSetup(false, true).message;
+  assert.match(noPrompt, /custom prompt is not coming through as <\.>/);
+  assert.ok(!/persona needs the name/.test(noPrompt), "must not blame the setting that is fine");
+
+  const noPersona = missingSetup(true, false).message;
+  assert.match(noPersona, /persona is not coming through/);
+  assert.ok(!/custom prompt is not coming through/.test(noPersona));
+
+  const neither = missingSetup(false, false).message;
+  assert.match(neither, /neither of the two required settings/);
+});
+
+test("every setup message still offers truncation as the second cause", () => {
+  for (const m of [missingSetup(false, true), missingSetup(true, false), missingSetup(false, false)]) {
+    assert.match(m.message, /Context Size/);
+    assert.ok(m.message.includes(CONTACT));
+    // Shown verbatim: this is the one class of failure a user can act on.
+    assert.equal(userFacingMessage(m), m.message);
+  }
 });
 
 test("shapes Janitor cannot produce never tell the user to fix them", () => {
@@ -47,7 +63,7 @@ test("a genuine bug reports itself without leaking internals", () => {
 });
 
 test("nobody is called a dingus", () => {
-  for (const e of [TRUNCATED_CARD, NO_CARD, NO_GREETING, TOO_FEW_MESSAGES, new Error("x")]) {
+  for (const e of [missingSetup(false, false), NO_CARD, NO_GREETING, TOO_FEW_MESSAGES, new Error("x")]) {
     assert.ok(!/dingus/i.test(userFacingMessage(e)));
   }
 });