diff --git a/.archgate/lint/oxlint.ts b/.archgate/lint/oxlint.ts
new file mode 100644
index 00000000..34531794
--- /dev/null
+++ b/.archgate/lint/oxlint.ts
@@ -0,0 +1,151 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright 2026 Archgate
+
+// Custom oxlint JS plugin: validate `type:` literals passed to
+// inquirer.prompt() against the prompt types registered by the installed
+// inquirer version.
+//
+// Why this exists: inquirer v14 removed the legacy "list" prompt type
+// (renamed "select" in v10), which crashed `archgate login` at runtime with
+// 'Prompt type "list" is not registered'. Nothing else can catch this class
+// of bug statically or in CI:
+//   - tsc cannot: inquirer's legacy prompt() types accept ANY `type: string`
+//     via the CustomQuestion escape hatch that exists for registerPrompt().
+//   - tests cannot: interactive prompts need a TTY, so every test mocks the
+//     inquirer module entirely and the runtime prompt registry never runs.
+// The invariant is purely syntactic, so it belongs in the linter.
+//
+// The registered set is read from the installed inquirer at plugin load, so
+// the rule self-updates on dependency bumps — a future rename/removal makes
+// stale call sites fail lint in the bump PR itself.
+//
+// The plugin runs natively as TypeScript under Bun, so there is no build step.
+
+/** Minimal ESTree-ish node shape. The oxlint AST is ESLint-compatible. */
+type AstNode = { type: string } & Record<string, unknown>;
+
+/** Narrow an unknown value to an AST node (an object with a string `type`). */
+function asNode(value: unknown): AstNode | undefined {
+  if (
+    value !== null &&
+    typeof value === "object" &&
+    typeof (value as { type?: unknown }).type === "string"
+  ) {
+    return value as AstNode;
+  }
+  return undefined;
+}
+
+/**
+ * Prompt types registered by the INSTALLED inquirer, read at plugin load.
+ *
+ * Deliberately not a hardcoded allowlist: when a future inquirer version
+ * renames or removes a prompt type (as v10 did with "list" -> "select"),
+ * the registry shrinks and stale call sites fail `bun run lint` immediately
+ * in the dependency-bump PR — no manual list maintenance.
+ *
+ * If inquirer ever changes the registry's API shape, the loud throw below
+ * fails the whole lint run rather than silently disabling the rule.
+ */
+const { default: inquirer } = await import("inquirer");
+const REGISTERED_PROMPT_TYPES = new Set(Object.keys(inquirer.prompt.prompts));
+if (REGISTERED_PROMPT_TYPES.size === 0) {
+  throw new Error(
+    "archgate/valid-inquirer-prompt-type: inquirer.prompt.prompts is empty — the registry API may have changed; update .archgate/lint/oxlint.ts"
+  );
+}
+
+/** True when the callee is exactly `inquirer.prompt`. */
+function isInquirerPromptCallee(callee: AstNode | undefined): boolean {
+  if (callee?.type !== "MemberExpression") return false;
+  const object = asNode(callee.object);
+  const property = asNode(callee.property);
+  return (
+    object?.type === "Identifier" &&
+    object.name === "inquirer" &&
+    property?.type === "Identifier" &&
+    property.name === "prompt"
+  );
+}
+
+/**
+ * Collect the question ObjectExpressions from inquirer.prompt() arguments.
+ * Handles both the single-object form `prompt({...})` and the array form
+ * `prompt([{...}, {...}])`.
+ */
+function questionObjects(args: unknown): AstNode[] {
+  const result: AstNode[] = [];
+  const list = Array.isArray(args) ? args : [];
+  for (const arg of list) {
+    const node = asNode(arg);
+    if (node?.type === "ObjectExpression") {
+      result.push(node);
+    } else if (node?.type === "ArrayExpression") {
+      const elements = Array.isArray(node.elements) ? node.elements : [];
+      for (const element of elements) {
+        const child = asNode(element);
+        if (child?.type === "ObjectExpression") result.push(child);
+      }
+    }
+  }
+  return result;
+}
+
+/** Find the value node of the `type` property in a question object, if any. */
+function typeValueNode(question: AstNode): AstNode | undefined {
+  const properties = Array.isArray(question.properties)
+    ? question.properties
+    : [];
+  for (const item of properties) {
+    const property = asNode(item);
+    if (property?.type !== "Property") continue;
+    const key = asNode(property.key);
+    const keyName =
+      key?.type === "Identifier"
+        ? key.name
+        : key?.type === "Literal"
+          ? key.value
+          : undefined;
+    if (keyName !== "type") continue;
+    return asNode(property.value);
+  }
+  return undefined;
+}
+
+interface ReportDescriptor {
+  node: AstNode;
+  message: string;
+}
+
+interface RuleContext {
+  report(descriptor: ReportDescriptor): void;
+}
+
+const validInquirerPromptType = {
+  create(context: RuleContext) {
+    return {
+      CallExpression(node: AstNode) {
+        if (!isInquirerPromptCallee(asNode(node.callee))) return;
+
+        for (const question of questionObjects(node.arguments)) {
+          const value = typeValueNode(question);
+          if (value?.type !== "Literal" || typeof value.value !== "string")
+            continue;
+          if (REGISTERED_PROMPT_TYPES.has(value.value)) continue;
+
+          context.report({
+            node: value,
+            message: `Prompt type "${value.value}" is not registered in the installed inquirer and will crash at runtime. Registered types: ${[...REGISTERED_PROMPT_TYPES].join(", ")}. (The legacy "list" type was renamed "select" in inquirer v10.)`,
+          });
+        }
+      },
+    };
+  },
+};
+
+const plugin = {
+  meta: { name: "archgate" },
+  rules: { "valid-inquirer-prompt-type": validInquirerPromptType },
+};
+
+export default plugin;
diff --git a/.claude/agent-memory/archgate-developer/MEMORY.md b/.claude/agent-memory/archgate-developer/MEMORY.md
index 4b8e5983..5aae525f 100644
--- a/.claude/agent-memory/archgate-developer/MEMORY.md
+++ b/.claude/agent-memory/archgate-developer/MEMORY.md
@@ -23,6 +23,7 @@ Skipping steps 2 or 3 is a workflow violation. The user should NEVER have to inv
 ## Approach Guidance
 
 - [No prod changes for testability](feedback_no_prod_changes_for_tests.md) — mock implementations in tests (spyOn os.homedir works cross-module); never alter prod semantics for test isolation
+- [Pick the right enforcement layer](feedback_prefer_tests_over_adr_rules.md) — static syntactic invariants → custom oxlint rule in `.archgate/lint/oxlint.ts`; tests are for executable behavior; ADR .rules.ts for cross-file/governance checks
 
 ## Known Bugs
 
diff --git a/.claude/agent-memory/archgate-developer/feedback_prefer_tests_over_adr_rules.md b/.claude/agent-memory/archgate-developer/feedback_prefer_tests_over_adr_rules.md
new file mode 100644
index 00000000..2b6eed85
--- /dev/null
+++ b/.claude/agent-memory/archgate-developer/feedback_prefer_tests_over_adr_rules.md
@@ -0,0 +1,18 @@
+---
+name: pick-the-right-enforcement-layer
+description: Static syntactic invariants belong in a custom oxlint rule (.archgate/lint/oxlint.ts), not in ADR .rules.ts and not in tests
+metadata:
+  type: feedback
+---
+
+Pick the enforcement layer by the nature of the invariant — don't default to ADR rules.
+
+**Why:** After the inquirer v14 `"list"` → `"select"` crash, I first drafted an ARCH-019 `.rules.ts` allowlist rule — user rejected it ("making an adr rule is stupid. we should make a proper test"). I then wrote a bun test scanning source files — user rejected that too ("if we have no tty, then this is more a linting rule than proper testing"). The final shape is a custom oxlint JS plugin rule (`archgate/valid-inquirer-prompt-type` in `.archgate/lint/oxlint.ts`), which gets real AST access instead of line-scanning and runs in the existing `bun run lint` gate.
+
+**How to apply:**
+
+- **Tests** verify _behavior_ — if the check can't actually execute the code path (e.g. interactive prompts with no TTY in CI), it is not a test, no matter where the file lives.
+- **Custom oxlint rules** (`.archgate/lint/oxlint.ts`, registered in `.oxlintrc.json` `jsPlugins`, enabled as `archgate/<rule>`) enforce _static syntactic invariants_ — pattern X in source must/must-not look like Y. AST-based, precise spans, IDE-visible.
+- **ADR `.rules.ts`** are for _project-structure/governance checks_ that don't fit a per-file lint model (cross-file sync, docs parity, dependency policy).
+- `.archgate/lint/` is the archgate-standard home for ADR-complementing linter rules (see its README); the plugin file is NOT in tsconfig `include` or knip `project`, but oxlint lints it, so it must itself pass all oxlint rules.
+- **oxlint jsPlugins have full module resolution and top-level await** — a plugin can `await import("inquirer")` at load and derive its allowlist from the installed dependency's runtime state (e.g. `Object.keys(inquirer.prompt.prompts)`). Prefer this over hardcoded allowlists: the rule then self-updates on dependency bumps and stale call sites fail lint in the bump PR itself. Guard with a loud throw if the upstream API shape changes, so the rule can never silently disable itself.
diff --git a/.oxlintrc.json b/.oxlintrc.json
index 4d26490e..17968f41 100644
--- a/.oxlintrc.json
+++ b/.oxlintrc.json
@@ -1,5 +1,5 @@
 {
-  "jsPlugins": ["./lint/expect-expect.ts"],
+  "jsPlugins": ["./lint/expect-expect.ts", "./.archgate/lint/oxlint.ts"],
   "categories": {
     "correctness": "error",
     "pedantic": "error",
@@ -10,6 +10,7 @@
     "max-lines-per-function": "off",
     "max-nested-callbacks": "off",
     "max-depth": "off",
+    "archgate/valid-inquirer-prompt-type": "error",
     "no-await-in-loop": "warn",
     "no-inline-comments": "off",
     "prefer-top-level-await": "off",
diff --git a/src/commands/adr/create.ts b/src/commands/adr/create.ts
index b551310b..81b80d25 100644
--- a/src/commands/adr/create.ts
+++ b/src/commands/adr/create.ts
@@ -65,7 +65,7 @@ export function registerAdrCreateCommand(adr: Command) {
           const answers = await withPromptFix(() =>
             inquirer.prompt([
               {
-                type: "list",
+                type: "select",
                 name: "domain",
                 message: "Domain:",
                 choices: choices.map((d) => ({ name: d, value: d })),
diff --git a/src/commands/adr/sync.ts b/src/commands/adr/sync.ts
index bf9351da..305ff5da 100644
--- a/src/commands/adr/sync.ts
+++ b/src/commands/adr/sync.ts
@@ -402,7 +402,7 @@ export function registerAdrSyncCommand(adr: Command) {
             const { choice } = await withPromptFix(() =>
               inquirer.prompt([
                 {
-                  type: "list",
+                  type: "select",
                   name: "choice",
                   message: `${diff.adrId}: What would you like to do?`,
                   choices: [
diff --git a/src/commands/init.ts b/src/commands/init.ts
index 0f40844d..43574018 100644
--- a/src/commands/init.ts
+++ b/src/commands/init.ts
@@ -219,7 +219,7 @@ async function runGreenfieldWizard(projectRoot: string): Promise<void> {
   const { wantPacks } = await withPromptFix(() =>
     inquirer.prompt([
       {
-        type: "list",
+        type: "select",
         name: "wantPacks",
         message:
           "No existing ADRs detected. Would you like to import starter packs?",
diff --git a/src/helpers/editor-detect.ts b/src/helpers/editor-detect.ts
index 303ed737..4f582f7a 100644
--- a/src/helpers/editor-detect.ts
+++ b/src/helpers/editor-detect.ts
@@ -102,7 +102,7 @@ export async function promptSingleEditorSelection(
   const { selected } = await withPromptFix(() =>
     inquirer.prompt([
       {
-        type: "list",
+        type: "select",
         name: "selected",
         message: "Select editor:",
         choices: detected.map((e) => ({
diff --git a/src/helpers/login-flow.ts b/src/helpers/login-flow.ts
index 244c9b6a..9b20e2b1 100644
--- a/src/helpers/login-flow.ts
+++ b/src/helpers/login-flow.ts
@@ -132,7 +132,7 @@ async function runSignupPrompt(
   if (!editor) {
     const ans = await withPromptFix(() =>
       inquirer.prompt({
-        type: "list",
+        type: "select",
         name: "editor",
         message: "Which editor will you use with archgate?",
         choices: [