diff --git a/packages/omo-codex/plugin/components/start-work-continuation/test/boulder-reader.test.ts b/packages/omo-codex/plugin/components/start-work-continuation/test/boulder-reader.test.ts
new file mode 100644
index 000000000..f4ba8739a
--- /dev/null
+++ b/packages/omo-codex/plugin/components/start-work-continuation/test/boulder-reader.test.ts
@@ -0,0 +1,63 @@
+import { describe, expect, it } from "vitest";
+
+import { parsePlanChecklist } from "../src/boulder-reader.js";
+
+describe("start-work plan checklist parser", () => {
+	it("#given top-level completed and incomplete checkboxes #when parsed #then counts remaining and total", () => {
+		// given
+		const markdown = ["# Plan", "", "## TODOs", "- [ ] First", "- [x] Done", "- [X] Also done", "- [ ] Second"].join(
+			"\n",
+		);
+
+		// when
+		const checklist = parsePlanChecklist(markdown);
+
+		// then
+		expect(checklist).toEqual({ remaining: 2, total: 4, nextTaskLabel: "First" });
+	});
+
+	it("#given nested checkboxes #when parsed #then ignores non-column-zero items", () => {
+		// given
+		const markdown = ["## TODOs", "- [ ] Top-level", "  - [ ] Nested", "\t- [ ] Tab nested", "- [x] Complete"].join(
+			"\n",
+		);
+
+		// when
+		const checklist = parsePlanChecklist(markdown);
+
+		// then
+		expect(checklist).toEqual({ remaining: 1, total: 2, nextTaskLabel: "Top-level" });
+	});
+
+	it("#given checkboxes outside counted sections #when parsed #then ignores unrelated top-level tasks", () => {
+		// given
+		const markdown = [
+			"# Plan",
+			"- [ ] Preamble task",
+			"## TODOs",
+			"- [ ] Build hook",
+			"## Acceptance Criteria",
+			"- [ ] Acceptance item",
+			"## Final Verification Wave",
+			"- [x] Run tests",
+			"- [ ] Run smoke",
+		].join("\n");
+
+		// when
+		const checklist = parsePlanChecklist(markdown);
+
+		// then
+		expect(checklist).toEqual({ remaining: 2, total: 3, nextTaskLabel: "Build hook" });
+	});
+
+	it("#given all top-level tasks complete #when parsed #then next task is null", () => {
+		// given
+		const markdown = ["## TODOs", "- [x] First", "- [X] Second"].join("\n");
+
+		// when
+		const checklist = parsePlanChecklist(markdown);
+
+		// then
+		expect(checklist).toEqual({ remaining: 0, total: 2, nextTaskLabel: null });
+	});
+});
diff --git a/packages/omo-codex/plugin/components/start-work-continuation/test/cli.test.ts b/packages/omo-codex/plugin/components/start-work-continuation/test/cli.test.ts
new file mode 100644
index 000000000..6d6fd65d2
--- /dev/null
+++ b/packages/omo-codex/plugin/components/start-work-continuation/test/cli.test.ts
@@ -0,0 +1,124 @@
+import { spawnSync } from "node:child_process";
+import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { execPath } from "node:process";
+import { afterEach, describe, expect, it } from "vitest";
+
+const cleanupRoots: string[] = [];
+
+afterEach(() => {
+	for (const root of cleanupRoots.splice(0)) rmSync(root, { recursive: true, force: true });
+});
+
+describe("start-work continuation CLI", () => {
+	it("#given valid Stop stdin #when CLI runs #then stdout contains block JSON", () => {
+		// given
+		const cwd = createWorkspace(["codex:s1"]);
+		const payload = JSON.stringify(makePayload(cwd, false, "Stop"));
+
+		// when
+		const result = runCli("stop", payload);
+
+		// then
+		if (result.error !== undefined) throw result.error;
+		expect(result.status).toBe(0);
+		expect(result.stdout).toContain('"decision":"block"');
+	});
+
+	it("#given valid SubagentStop stdin #when CLI runs #then stdout contains block JSON", () => {
+		// given
+		const cwd = createWorkspace(["codex:s1"]);
+		const payload = JSON.stringify(makePayload(cwd, false, "SubagentStop"));
+
+		// when
+		const result = runCli("subagent-stop", payload);
+
+		// then
+		if (result.error !== undefined) throw result.error;
+		expect(result.status).toBe(0);
+		expect(result.stdout).toContain('"decision":"block"');
+	});
+
+	it("#given active stop hook stdin #when CLI runs #then stdout is empty and exit is zero", () => {
+		// given
+		const cwd = createWorkspace(["codex:s1"]);
+		const payload = JSON.stringify(makePayload(cwd, true, "Stop"));
+
+		// when
+		const result = runCli("stop", payload);
+
+		// then
+		if (result.error !== undefined) throw result.error;
+		expect(result.status).toBe(0);
+		expect(result.stdout).toBe("");
+	});
+
+	it("#given unrelated session stdin #when CLI runs #then stdout is empty and exit is zero", () => {
+		// given
+		const cwd = createWorkspace(["codex:other"]);
+		const payload = JSON.stringify(makePayload(cwd, false, "Stop"));
+
+		// when
+		const result = runCli("stop", payload);
+
+		// then
+		if (result.error !== undefined) throw result.error;
+		expect(result.status).toBe(0);
+		expect(result.stdout).toBe("");
+	});
+
+	it("#given malformed stdin #when CLI runs #then stdout is empty and exit is zero", () => {
+		// given
+		const payload = "{not-json";
+
+		// when
+		const result = runCli("stop", payload);
+
+		// then
+		if (result.error !== undefined) throw result.error;
+		expect(result.status).toBe(0);
+		expect(result.stdout).toBe("");
+	});
+});
+
+function runCli(subcommand: "stop" | "subagent-stop", input: string) {
+	return spawnSync(execPath, [join(process.cwd(), "dist", "cli.js"), "hook", subcommand], { input, encoding: "utf8" });
+}
+
+function createWorkspace(sessionIds: readonly string[]): string {
+	const root = mkdtempSync(join(tmpdir(), "codex-continuation-cli-"));
+	cleanupRoots.push(root);
+	mkdirSync(join(root, ".omo", "plans"), { recursive: true });
+	writeFileSync(join(root, ".omo", "plans", "plan.md"), "## TODOs\n\n- [ ] Task one\n");
+	const work = {
+		work_id: "w1",
+		active_plan: ".omo/plans/plan.md",
+		plan_name: "cli plan",
+		session_ids: sessionIds,
+		status: "active",
+	};
+	writeFileSync(
+		join(root, ".omo", "boulder.json"),
+		`${JSON.stringify({ schema_version: 2, active_work_id: "w1", works: { w1: work } })}\n`,
+	);
+	return root;
+}
+
+function makePayload(
+	cwd: string,
+	stopHookActive: boolean,
+	eventName: "Stop" | "SubagentStop",
+): Record<string, string | boolean> {
+	return {
+		session_id: "s1",
+		turn_id: "t1",
+		transcript_path: "",
+		cwd,
+		hook_event_name: eventName,
+		model: "gpt-5.5",
+		permission_mode: "default",
+		stop_hook_active: stopHookActive,
+		last_assistant_message: "done",
+	};
+}
diff --git a/packages/omo-codex/plugin/components/start-work-continuation/test/codex-hook.test.ts b/packages/omo-codex/plugin/components/start-work-continuation/test/codex-hook.test.ts
new file mode 100644
index 000000000..afa95f502
--- /dev/null
+++ b/packages/omo-codex/plugin/components/start-work-continuation/test/codex-hook.test.ts
@@ -0,0 +1,160 @@
+import { join } from "node:path";
+import { describe, expect, it } from "vitest";
+
+import { runStopHook } from "../src/codex-hook.js";
+import type { ReadonlyFileSystem, StopInput } from "../src/types.js";
+
+const WORKSPACE = "/repo";
+const BOULDER_PATH = join(WORKSPACE, ".omo", "boulder.json");
+const PLAN_PATH = join(WORKSPACE, ".omo", "plans", "plan.md");
+const LEDGER_PATH = join(WORKSPACE, ".omo", "start-work", "ledger.jsonl");
+
+describe("start-work Stop hook", () => {
+	it("#given stop hook is already active #when hook runs #then returns empty output", () => {
+		// given
+		const fs = createMemoryFs();
+		const input = { ...createStopInput(), stop_hook_active: true };
+
+		// when
+		const output = runStopHook(input, fs);
+
+		// then
+		expect(output).toBe("");
+	});
+
+	it("#given active codex work with remaining top-level tasks #when hook runs #then returns block JSON", () => {
+		// given
+		const fs = createMemoryFs({
+			[BOULDER_PATH]: createBoulderJson({
+				sessionIds: ["codex:sess_abc"],
+				status: "active",
+				worktreePath: "/tmp/worktree",
+			}),
+			[PLAN_PATH]: ["# Plan", "", "## TODOs", "- [ ] First", "- [x] Done", "- [ ] Second"].join("\n"),
+		});
+
+		// when
+		const output = runStopHook(createStopInput(), fs);
+
+		// then
+		const parsed = parseBlockOutput(output);
+		expect(parsed.decision).toBe("block");
+		expect(parsed.reason).toContain("- Plan: `launch-plan`");
+		expect(parsed.reason).toContain(`- Plan file: \`${PLAN_PATH}\``);
+		expect(parsed.reason).toContain(`- Boulder state: \`${BOULDER_PATH}\``);
+		expect(parsed.reason).toContain("- Remaining top-level checkboxes: `2` of `3`");
+		expect(parsed.reason).toContain("- Next incomplete task: `First`");
+		expect(parsed.reason).toContain("- Worktree: `/tmp/worktree`");
+		expect(parsed.reason).toContain(`- Ledger: \`${LEDGER_PATH}\``);
+		expect(parsed.reason).toContain("- Your session id in boulder.json: `codex:sess_abc`");
+	});
+
+	it("#given active work belongs to another harness #when hook runs #then returns empty output", () => {
+		// given
+		const fs = createMemoryFs({
+			[BOULDER_PATH]: createBoulderJson({ sessionIds: ["opencode:sess_abc"], status: "active" }),
+			[PLAN_PATH]: "- [ ] First",
+		});
+
+		// when
+		const output = runStopHook(createStopInput(), fs);
+
+		// then
+		expect(output).toBe("");
+	});
+
+	it("#given bare legacy session id #when hook runs #then returns empty output", () => {
+		// given
+		const fs = createMemoryFs({
+			[BOULDER_PATH]: createBoulderJson({ sessionIds: ["sess_abc"], status: "active" }),
+			[PLAN_PATH]: "- [ ] First",
+		});
+
+		// when
+		const output = runStopHook(createStopInput(), fs);
+
+		// then
+		expect(output).toBe("");
+	});
+
+	it("#given completed boulder work #when hook runs #then returns empty output", () => {
+		// given
+		const fs = createMemoryFs({
+			[BOULDER_PATH]: createBoulderJson({ sessionIds: ["codex:sess_abc"], status: "completed" }),
+			[PLAN_PATH]: "- [ ] First",
+		});
+
+		// when
+		const output = runStopHook(createStopInput(), fs);
+
+		// then
+		expect(output).toBe("");
+	});
+
+	it("#given malformed input #when hook runs #then returns empty output", () => {
+		// given
+		const fs = createMemoryFs();
+
+		// when
+		const output = runStopHook({ hook_event_name: "Stop", session_id: 123 }, fs);
+
+		// then
+		expect(output).toBe("");
+	});
+});
+
+type BoulderInput = {
+	readonly sessionIds: readonly string[];
+	readonly status: "active" | "completed" | "paused" | "abandoned";
+	readonly worktreePath?: string;
+};
+
+function createStopInput(): StopInput {
+	return {
+		hook_event_name: "Stop",
+		session_id: "sess_abc",
+		turn_id: "turn_1",
+		transcript_path: "",
+		cwd: WORKSPACE,
+		model: "gpt-5.5",
+		permission_mode: "default",
+		stop_hook_active: false,
+		last_assistant_message: "done",
+	};
+}
+
+function createBoulderJson(input: BoulderInput): string {
+	const work = {
+		work_id: "work_1",
+		active_plan: ".omo/plans/plan.md",
+		plan_name: "launch-plan",
+		status: input.status,
+		session_ids: input.sessionIds,
+		...(input.worktreePath === undefined ? {} : { worktree_path: input.worktreePath }),
+	};
+	return JSON.stringify({ schema_version: 2, active_work_id: "work_1", works: { work_1: work } });
+}
+
+function createMemoryFs(files: Record<string, string> = {}): ReadonlyFileSystem {
+	return {
+		readFileSync(path, encoding) {
+			expect(encoding).toBe("utf8");
+			const value = files[path];
+			if (value === undefined) throw new Error(`Missing fixture: ${path}`);
+			return value;
+		},
+	};
+}
+
+function parseBlockOutput(output: string): { readonly decision: "block"; readonly reason: string } {
+	const parsed: unknown = JSON.parse(output);
+	if (!isRecord(parsed)) throw new Error("Expected object output");
+	if (parsed["decision"] !== "block") throw new Error("Expected block decision");
+	const reason = parsed["reason"];
+	if (typeof reason !== "string") throw new Error("Expected string reason");
+	return { decision: "block", reason };
+}
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+	return typeof value === "object" && value !== null && !Array.isArray(value);
+}