feat(cli): parsePromptSnapshotArgs for meta prompt-snapshot [FR-004]

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: dmealing

server/typescript/packages/cli/src/lib/args.ts

@@ -100,6 +100,33 @@ export function parseVerifyArgs(argv: string[]): VerifyFlags {
   };
 }
 
+// ---------------------------------------------------------------------------
+// prompt-snapshot flags
+// ---------------------------------------------------------------------------
+
+export interface PromptSnapshotFlags {
+  /** Compare against committed snapshots and fail on drift; never write. */
+  check: boolean;
+  /** Directory (relative to cwd) holding provider-resolved template text. */
+  prompts: string | undefined;
+}
+
+export function parsePromptSnapshotArgs(argv: string[]): PromptSnapshotFlags {
+  const { values } = parseArgs({
+    args: argv,
+    options: {
+      check: { type: "boolean", default: false },
+      prompts: { type: "string" },
+    },
+    strict: true,
+    allowPositionals: false,
+  });
+  return {
+    check: !!values.check,
+    prompts: values.prompts,
+  };
+}
+
 // ---------------------------------------------------------------------------
 // migrate flags
 // ---------------------------------------------------------------------------

server/typescript/packages/cli/test/unit/args-prompt-snapshot.test.ts

@@ -0,0 +1,23 @@
+import { describe, test, expect } from "bun:test";
+import { parsePromptSnapshotArgs } from "../../src/lib/args.js";
+
+describe("parsePromptSnapshotArgs", () => {
+  test("defaults: check false, prompts undefined", () => {
+    expect(parsePromptSnapshotArgs([])).toEqual({ check: false, prompts: undefined });
+  });
+  test("--check sets check true", () => {
+    expect(parsePromptSnapshotArgs(["--check"])).toEqual({ check: true, prompts: undefined });
+  });
+  test("--prompts <dir> is captured", () => {
+    expect(parsePromptSnapshotArgs(["--prompts", "templates"])).toEqual({
+      check: false,
+      prompts: "templates",
+    });
+  });
+  test("throws on an unknown flag", () => {
+    expect(() => parsePromptSnapshotArgs(["--bogus"])).toThrow();
+  });
+  test("throws on a positional argument", () => {
+    expect(() => parsePromptSnapshotArgs(["extra"])).toThrow();
+  });
+});