fix(3808): codex adapter activates TEXT_MODE when request_user_input is unavailable (#84)

When Codex reports `request_user_input` as unavailable (Default mode), the
Codex skill adapter's Execute-mode-fallback section now explicitly instructs
the agent to append `--text` to `{{GSD_ARGS}}` to activate the workflow's
built-in TEXT_MODE branching. This ensures every AskUserQuestion gate is
handled consistently through the workflow's own text-mode mechanism rather
than ad-hoc plain-text fallback, and eliminates any path to silent-default
selection (#3018 / #3808).

Adds regression test bug-3808-codex-adapter-text-mode-fallback.test.cjs with
typed semantic-flag assertions covering gsd-plan-phase, gsd-discuss-phase,
gsd-execute-phase, and gsd-verify-work.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

.changeset/3808-codex-adapter-text-mode-fallback.md

@@ -0,0 +1,5 @@
+---
+type: Fixed
+pr: 3808
+---
+**Codex adapter now activates TEXT_MODE when `request_user_input` is unavailable** — `bin/install.js:getCodexSkillAdapterHeader` previously told the agent only to "stop and present plain-text"; it now explicitly instructs the agent to append `--text` to `{{GSD_ARGS}}` so the workflow's built-in `TEXT_MODE` branching handles all `AskUserQuestion` gates consistently, eliminating silent-default selection in Codex Default mode (#3808).

bin/install.js

@@ -2579,7 +2579,7 @@ Multi-select workaround:
 - Codex has no \`multiSelect\`. Use sequential single-selects, or present a numbered freeform list asking the user to enter comma-separated numbers.
 
 Execute mode fallback:
-- When \`request_user_input\` is rejected or unavailable, you MUST stop and present the questions as a plain-text numbered list, then wait for the user's reply. Do NOT pick a default and continue (#3018).
+- When \`request_user_input\` is rejected or unavailable, activate TEXT_MODE: append \`--text\` to \`{{GSD_ARGS}}\` so the workflow's built-in text-mode branching takes over. Present every \`AskUserQuestion\` call as a plain-text numbered list, then stop and wait for the user's reply. Do NOT pick a default and continue (#3018 / #3808).
 - You may only proceed without a user answer when one of these is true:
   (a) the invocation included an explicit non-interactive flag (\`--auto\` or \`--all\`),
   (b) the user has explicitly approved a specific default for this question, or

tests/bug-3808-codex-adapter-text-mode-fallback.test.cjs

@@ -0,0 +1,155 @@
+/**
+ * Regression test for bug #3808.
+ *
+ * When Codex runs in Default mode, `request_user_input` is reported as
+ * unavailable. The Codex skill adapter must tell the agent to activate the
+ * workflow's built-in TEXT_MODE mechanism (`--text` flag) rather than either:
+ *   (a) silently picking a default value — the #3018 failure mode, or
+ *   (b) ad-hoc plain-text fallback that bypasses the workflow's own branching.
+ *
+ * Workflows (e.g. plan-phase.md) already have TEXT_MODE logic:
+ *   "Set TEXT_MODE=true if `--text` is present in $ARGUMENTS OR text_mode
+ *    from init JSON is true."
+ * The adapter must tell the agent to USE that mechanism when
+ * `request_user_input` is unavailable instead of inventing its own fallback
+ * or silently continuing with defaults.
+ *
+ * Test design: mirrors the typed-semantic-flag pattern from bug #3018 so that
+ * prose rewording doesn't break tests as long as the semantics stay correct.
+ */
+
+'use strict';
+
+process.env.GSD_TEST_MODE = '1';
+
+const { test, describe } = require('node:test');
+const assert = require('node:assert/strict');
+const path = require('node:path');
+
+const INSTALL = require(path.join(__dirname, '..', 'bin', 'install.js'));
+const { getCodexSkillAdapterHeader } = INSTALL;
+
+/**
+ * Extract the "Execute mode fallback" section text from the adapter header.
+ * Returns null if the section is missing. Section runs from the
+ * "Execute mode fallback:" label up to the next heading or </codex_skill_adapter> tag.
+ */
+function extractExecuteModeFallback(header) {
+  const m = header.match(/Execute mode fallback:\s*\n([\s\S]*?)(?=\n##\s|\n<\/codex_skill_adapter>)/);
+  return m ? m[1].trim() : null;
+}
+
+/**
+ * Parse the Execute-mode-fallback section into a typed semantic-flag record.
+ *
+ * Flags for bug #3808 (TEXT_MODE activation):
+ *   activatesTextMode       — does the prose tell the agent to activate TEXT_MODE / use --text?
+ *   instructsStop           — does the prose tell the agent to stop/halt/wait?
+ *   presentsPlainText       — does the prose mention plain-text / numbered-list presentation?
+ *   silentlyPicksDefaults   — (anti-pattern) does the prose instruct silent-default picking?
+ */
+function parseExecuteModeFallbackFor3808(section) {
+  if (!section || typeof section !== 'string') {
+    return {
+      ok: false,
+      sectionLength: 0,
+      activatesTextMode: false,
+      instructsStop: false,
+      presentsPlainText: false,
+      silentlyPicksDefaults: false,
+    };
+  }
+
+  const lower = section.toLowerCase();
+
+  // (a) TEXT_MODE activation — adapter must tell the agent to use the workflow's
+  // built-in text mode mechanism when request_user_input is unavailable.
+  // Accept either: explicit "--text" flag mention OR "text_mode" / "text mode"
+  // paired with context showing it is being SET/ACTIVATED (not just referenced).
+  const mentionsTextFlag   = section.includes('--text');
+  const mentionsTextModeOn = /text_mode\s*=\s*true|set\s+text_mode|activate\s+text.?mode|enable\s+text.?mode|text.?mode.*active|text.?mode.*on\b/i.test(section);
+  const activatesTextMode  = mentionsTextFlag || mentionsTextModeOn;
+
+  // (b) STOP/WAIT directive — the agent must halt instead of proceeding silently.
+  const instructsStop = /\b(stop|halt|wait)\b/.test(lower);
+
+  // (c) Plain-text fallback presentation.
+  const presentsPlainText = /plain.?text|numbered list/.test(lower);
+
+  // Anti-pattern guard — the prose that caused #3018 and resurfaces in #3808.
+  const silentlyPicksDefaults = /pick (a |the )?(reasonable|sensible|sane) default/i.test(section);
+
+  return {
+    ok: true,
+    sectionLength: section.length,
+    activatesTextMode,
+    instructsStop,
+    presentsPlainText,
+    silentlyPicksDefaults,
+  };
+}
+
+describe('bug #3808: codex skill adapter activates TEXT_MODE when request_user_input is unavailable', () => {
+  const SKILL_NAMES = ['gsd-plan-phase', 'gsd-discuss-phase', 'gsd-execute-phase', 'gsd-verify-work'];
+
+  test('getCodexSkillAdapterHeader is exported', () => {
+    assert.equal(typeof getCodexSkillAdapterHeader, 'function');
+  });
+
+  test('Execute mode fallback section exists for all key skills', () => {
+    for (const skillName of SKILL_NAMES) {
+      const header = getCodexSkillAdapterHeader(skillName);
+      const section = extractExecuteModeFallback(header);
+      assert.ok(section !== null && section.length > 0,
+        `${skillName}: Execute mode fallback section must exist and have content`);
+    }
+  });
+
+  for (const skillName of SKILL_NAMES) {
+    test(`${skillName}: fallback activates TEXT_MODE (--text flag or text_mode=true) when request_user_input is unavailable`, () => {
+      const header = getCodexSkillAdapterHeader(skillName);
+      const section = extractExecuteModeFallback(header);
+      const parsed = parseExecuteModeFallbackFor3808(section);
+      assert.equal(parsed.activatesTextMode, true,
+        `${skillName}: fallback must instruct the agent to activate TEXT_MODE (mention --text flag or text_mode=true/active) when request_user_input is unavailable (#3808). Section was:\n${section}`);
+    });
+
+    test(`${skillName}: fallback instructs STOP/WAIT (not silent continuation)`, () => {
+      const header = getCodexSkillAdapterHeader(skillName);
+      const section = extractExecuteModeFallback(header);
+      const parsed = parseExecuteModeFallbackFor3808(section);
+      assert.equal(parsed.instructsStop, true,
+        `${skillName}: fallback must include stop/halt/wait instruction. Section was:\n${section}`);
+    });
+
+    test(`${skillName}: fallback does NOT contain silent-default anti-pattern`, () => {
+      const header = getCodexSkillAdapterHeader(skillName);
+      const section = extractExecuteModeFallback(header);
+      const parsed = parseExecuteModeFallbackFor3808(section);
+      assert.equal(parsed.silentlyPicksDefaults, false,
+        `${skillName}: regression — fallback must NOT instruct the agent to pick defaults autonomously (#3018 / #3808). Section was:\n${section}`);
+    });
+  }
+
+  test('typed semantic-record snapshot for gsd-plan-phase — full contract', () => {
+    const section = extractExecuteModeFallback(getCodexSkillAdapterHeader('gsd-plan-phase'));
+    const parsed = parseExecuteModeFallbackFor3808(section);
+    assert.deepStrictEqual(
+      {
+        ok: parsed.ok,
+        activatesTextMode: parsed.activatesTextMode,
+        instructsStop: parsed.instructsStop,
+        presentsPlainText: parsed.presentsPlainText,
+        silentlyPicksDefaults: parsed.silentlyPicksDefaults,
+      },
+      {
+        ok: true,
+        activatesTextMode: true,
+        instructsStop: true,
+        presentsPlainText: true,
+        silentlyPicksDefaults: false,
+      },
+      `gsd-plan-phase: full TEXT_MODE fallback contract violated (#3808). Section was:\n${section}`,
+    );
+  });
+});