diff --git a/src/brain/index.test.ts b/src/brain/index.test.ts
index f2b69e2..0bddd30 100644
--- a/src/brain/index.test.ts
+++ b/src/brain/index.test.ts
@@ -399,3 +399,55 @@ describe("S8: regression on existing methods", () => {
     expect(typeof Brain.load).toBe("function");
   });
 });
+
+describe("Brain.createDebug", () => {
+  test("D1: returns a Brain with debug=true, the supplied personality, and no disk file created", async () => {
+    const { existsSync } = await import("fs");
+    const { resolve } = await import("path");
+
+    const before = existsSync(resolve(process.cwd(), "brainbox.db"));
+
+    const brain = await Brain.createDebug({ personality: "test-personality-Q" });
+
+    expect(brain).toBeInstanceOf(Brain);
+    expect(brain.debug).toBe(true);
+    expect(brain.brainbase.baseSystemPrompt).toBe("test-personality-Q");
+    expect(brain.brainbase.displayName).toBe("Debug Brain");
+
+    const after = existsSync(resolve(process.cwd(), "brainbox.db"));
+    expect(after).toBe(before);
+  });
+
+  test("D2: createDailySchedule on a debug brain returns a schedule and does NOT add a fact to the DB", async () => {
+    const brain = await Brain.createDebug({ personality: "p" });
+    const today = new Date(2026, 5, 5);
+    const tomorrow = new Date(2026, 5, 6);
+    const tomorrowKey = formatDateKey(tomorrow);
+
+    const schedule = await brain.createDailySchedule(today, "msg");
+    expect(schedule).not.toBeNull();
+    expect(schedule).toHaveLength(48);
+
+    const facts = await brain.db.getTopicFacts(`daily-schedule:${tomorrowKey}`, {
+      spaceName: brain.space.name,
+    });
+    expect(facts).toHaveLength(0);
+  });
+
+  test("D3: createMonthlySchedule on a debug brain returns a schedule and does NOT add a fact to the DB", async () => {
+    const brain = await Brain.createDebug({ personality: "p" });
+    const today = new Date(2026, 0, 15);
+    const expected = nextMonth(today);
+    const monthKey = `${expected.year}-${String(expected.month + 1).padStart(2, "0")}`;
+
+    const schedule = await brain.createMonthlySchedule(today, "msg");
+    expect(schedule).not.toBeNull();
+    expect(schedule).toHaveLength(expected.daysInMonth);
+
+    const facts = await brain.db.getTopicFacts(
+      `monthly-schedule:${monthKey}`,
+      { spaceName: brain.space.name },
+    );
+    expect(facts).toHaveLength(0);
+  });
+});
diff --git a/src/brain/index.ts b/src/brain/index.ts
index 0adc47a..658e157 100644
--- a/src/brain/index.ts
+++ b/src/brain/index.ts
@@ -21,6 +21,11 @@ import {
   nextMonth,
   pad2,
 } from "./schedule";
+import { BadRequestResponseError } from "@openrouter/sdk/models/errors";
+
+export interface DebugOptions {
+  personality: string;
+}
 
 export class Brain {
   private availabilityCache: Map<string, Availability[]> = new Map();
@@ -29,6 +34,7 @@ export class Brain {
     public db: IdentityDB,
     public space: Space,
     public brainbase: BrainItem,
+    public debug: boolean = false,
   ) {}
 
   async createDailySchedule(
@@ -62,37 +68,44 @@ export class Brain {
         jsonSchema: dailyScheduleSchema,
       });
 
-      await this.db.addFact({
-        spaceName: this.space.name,
-        statement: JSON.stringify(schedule),
-        summary: `Daily schedule for ${dateKey} (${schedule.length} slots)`,
-        source: "createDailySchedule",
-        confidence: 1.0,
-        topics: [
-          {
-            name: topicName,
-            category: "temporal",
-            granularity: "concrete",
-            role: "schedule",
-          },
-          {
-            name: "daily-schedule",
-            category: "concept",
-            granularity: "abstract",
-            role: "schedule",
-          },
-          {
-            name: dateKey,
-            category: "temporal",
-            granularity: "concrete",
-            role: "date",
-          },
-        ],
-      });
+      if (!this.debug) {
+        await this.db.addFact({
+          spaceName: this.space.name,
+          statement: JSON.stringify(schedule),
+          summary: `Daily schedule for ${dateKey} (${schedule.length} slots)`,
+          source: "createDailySchedule",
+          confidence: 1.0,
+          topics: [
+            {
+              name: topicName,
+              category: "temporal",
+              granularity: "concrete",
+              role: "schedule",
+            },
+            {
+              name: "daily-schedule",
+              category: "concept",
+              granularity: "abstract",
+              role: "schedule",
+            },
+            {
+              name: dateKey,
+              category: "temporal",
+              granularity: "concrete",
+              role: "date",
+            },
+          ],
+        });
+      }
 
       return schedule;
     } catch (error) {
-      const reason = error instanceof Error ? error.message : String(error);
+      let reason =
+        error instanceof Error
+          ? error.message + `(${error.name})`
+          : String(error);
+      if (error instanceof BadRequestResponseError)
+        reason = reason + `${error.body}`;
       logger.error(`createDailySchedule failed: ${reason}`);
       return null;
     }
@@ -125,33 +138,35 @@ export class Brain {
         jsonSchema: monthlyScheduleSchema,
       });
 
-      await this.db.addFact({
-        spaceName: this.space.name,
-        statement: JSON.stringify(schedule),
-        summary: `Monthly schedule for ${monthKey} (${schedule.length} days)`,
-        source: "createMonthlySchedule",
-        confidence: 1.0,
-        topics: [
-          {
-            name: topicName,
-            category: "temporal",
-            granularity: "concrete",
-            role: "schedule",
-          },
-          {
-            name: "monthly-schedule",
-            category: "concept",
-            granularity: "abstract",
-            role: "schedule",
-          },
-          {
-            name: monthKey,
-            category: "temporal",
-            granularity: "concrete",
-            role: "period",
-          },
-        ],
-      });
+      if (!this.debug) {
+        await this.db.addFact({
+          spaceName: this.space.name,
+          statement: JSON.stringify(schedule),
+          summary: `Monthly schedule for ${monthKey} (${schedule.length} days)`,
+          source: "createMonthlySchedule",
+          confidence: 1.0,
+          topics: [
+            {
+              name: topicName,
+              category: "temporal",
+              granularity: "concrete",
+              role: "schedule",
+            },
+            {
+              name: "monthly-schedule",
+              category: "concept",
+              granularity: "abstract",
+              role: "schedule",
+            },
+            {
+              name: monthKey,
+              category: "temporal",
+              granularity: "concrete",
+              role: "period",
+            },
+          ],
+        });
+      }
 
       return schedule;
     } catch (error) {
@@ -169,6 +184,13 @@ export class Brain {
       const cached = this.availabilityCache.get(dateKey);
       if (cached) return cached;
 
+      if (this.debug) {
+        logger.warn(
+          "getTodayScheduledAvailability requires a persisted daily schedule; debug brains have no DB. Use deriveAvailabilityFromSchedule(schedule) instead.",
+        );
+        return null;
+      }
+
       const topicName = `daily-schedule:${dateKey}`;
       const facts = await this.db.getTopicFacts(topicName, {
         spaceName: this.space.name,
@@ -176,19 +198,8 @@ export class Brain {
       if (facts.length === 0) return null;
 
       const dailySchedule = JSON.parse(facts[0]!.statement) as DailySchedule;
-
-      const instruction = await loadPrompt("SCHEDULE_AVAILABILITY");
-      const promptMessage = JSON.stringify({
-        schedule: dailySchedule,
-        personality: this.brainbase.baseSystemPrompt,
-      });
-
-      const availability = await llm.call<Availability[]>(llm.models.identity, {
-        instruction,
-        message: promptMessage,
-        jsonSchemaName: "availability",
-        jsonSchema: availabilitySchema,
-      });
+      const availability =
+        await this.deriveAvailabilityFromSchedule(dailySchedule);
 
       this.availabilityCache.set(dateKey, availability);
       return availability;
@@ -199,11 +210,35 @@ export class Brain {
     }
   }
 
+  async deriveAvailabilityFromSchedule(
+    schedule: DailySchedule,
+  ): Promise<Availability[]> {
+    try {
+      const instruction = await loadPrompt("SCHEDULE_AVAILABILITY");
+      const promptMessage = JSON.stringify({
+        schedule,
+        personality: this.brainbase.baseSystemPrompt,
+      });
+
+      return await llm.call<Availability[]>(llm.models.identity, {
+        instruction,
+        message: promptMessage,
+        jsonSchemaName: "availability",
+        jsonSchema: availabilitySchema,
+      });
+    } catch (error) {
+      const reason = error instanceof Error ? error.message : String(error);
+      logger.error(`deriveAvailabilityFromSchedule failed: ${reason}`);
+      throw error;
+    }
+  }
+
   removeScheduledAvailability(): void {
     this.availabilityCache.clear();
   }
 
   private async getMonthlySummaryForDay(target: Date): Promise<string | null> {
+    if (this.debug) return null;
     try {
       const monthKey = formatMonthKey(target);
       const topicName = `monthly-schedule:${monthKey}`;
@@ -222,6 +257,7 @@ export class Brain {
   }
 
   private async getHistoryFacts(): Promise<string> {
+    if (this.debug) return "";
     try {
       const topics = await this.db.listTopics({
         spaceName: this.space.name,
@@ -306,4 +342,25 @@ export class Brain {
 
     return new Brain(db, space, brain);
   }
+
+  static async createDebug(options: DebugOptions): Promise<Brain> {
+    const db = await IdentityDB.connect({
+      client: "sqlite",
+      filename: ":memory:",
+    });
+    await db.initialize();
+    const space = await db.upsertSpace({
+      name: "debug",
+      description: "Debug Brain",
+    });
+
+    const brainbase: BrainItem = {
+      brainId: "debug",
+      spaceName: "debug",
+      displayName: "Debug Brain",
+      baseSystemPrompt: options.personality,
+    };
+
+    return new Brain(db, space, brainbase, true);
+  }
 }
diff --git a/src/commands/brain.ts b/src/commands/brain.ts
index ac84bd0..1a8d68a 100644
--- a/src/commands/brain.ts
+++ b/src/commands/brain.ts
@@ -1,2 +1,11 @@
-// Manage brains
+import type { Command } from "commander";
+import { registerCommand } from "@/commands";
+
 export async function brain() {}
+
+export function register(program: Command): Command {
+  return registerCommand(program, {
+    name: "brain",
+    description: "Manage brains",
+  }).action(brain);
+}
diff --git a/src/commands/debug/index.ts b/src/commands/debug/index.ts
new file mode 100644
index 0000000..f04df16
--- /dev/null
+++ b/src/commands/debug/index.ts
@@ -0,0 +1,12 @@
+import type { Command } from "commander";
+import { registerCommand } from "@/commands";
+import { addScheduleSubcommand } from "./schedule";
+
+export function register(program: Command): Command {
+  return registerCommand(program, {
+    name: "debug",
+    description:
+      "Dry-run tools: exercise code paths without writing to the database or braindb",
+    configure: addScheduleSubcommand,
+  });
+}
diff --git a/src/commands/debug/schedule.test.ts b/src/commands/debug/schedule.test.ts
new file mode 100644
index 0000000..b89a369
--- /dev/null
+++ b/src/commands/debug/schedule.test.ts
@@ -0,0 +1,184 @@
+import { afterEach, beforeEach, describe, expect, mock, test } from "bun:test";
+import type { Availability, DailySchedule, MonthlySchedule } from "@/brain/schedule";
+
+interface RecordedCall {
+  model: unknown;
+  options: { jsonSchemaName?: string; message?: string };
+}
+
+const llmCalls: RecordedCall[] = [];
+
+function build48Slots(): DailySchedule {
+  const slots: DailySchedule = [];
+  for (let i = 0; i < 48; i++) {
+    const startHour = Math.floor(i / 2);
+    const startMin = (i % 2) * 30;
+    const start = `${String(startHour).padStart(2, "0")}:${String(startMin).padStart(2, "0")}`;
+    let end: string;
+    if (i === 47) {
+      end = "24:00";
+    } else {
+      const endHour = Math.floor((i + 1) / 2);
+      const endMin = ((i + 1) % 2) * 30;
+      end = `${String(endHour).padStart(2, "0")}:${String(endMin).padStart(2, "0")}`;
+    }
+    slots.push({ start, end, activity: `slot-${i}` });
+  }
+  return slots;
+}
+
+function buildAvailability(): Availability[] {
+  return [
+    { start: "00:00", end: "07:00", status: "offline" },
+    { start: "07:00", end: "23:30", status: "online" },
+    { start: "23:30", end: "24:00", status: "offline" },
+  ];
+}
+
+function buildMonthly(): MonthlySchedule {
+  return Array.from({ length: 30 }, (_, i) => ({
+    day: i + 1,
+    summary: `Day ${i + 1} summary`,
+  }));
+}
+
+const mockCall = mock(async (_model: unknown, options: any) => {
+  llmCalls.push({ model: _model, options });
+  if (options.jsonSchemaName === "daily-schedule") return build48Slots();
+  if (options.jsonSchemaName === "monthly-schedule") {
+    const match = (options.message as string).match(/\((\d+) days\)/);
+    const days = match ? parseInt(match[1]!, 10) : 30;
+    return Array.from({ length: days }, (_, i) => ({
+      day: i + 1,
+      summary: `Day ${i + 1} summary`,
+    }));
+  }
+  if (options.jsonSchemaName === "availability") return buildAvailability();
+  throw new Error(`unexpected jsonSchemaName: ${options.jsonSchemaName}`);
+});
+
+mock.module("@/openrouter", () => ({
+  llm: {
+    models: { conversation: "test-conv", identity: "test-id" },
+    call: mockCall,
+  },
+}));
+
+mock.module("@/config", () => ({
+  config: {
+    openrouterApiKey: "test-key",
+    dbPath: ":memory:",
+    braindbPath: "/tmp/brainbox-test-braindb-debug-schedule.json",
+  },
+}));
+
+const { runDebugScheduleDaily, runDebugScheduleMonthly } = await import(
+  "./schedule"
+);
+
+beforeEach(() => {
+  llmCalls.length = 0;
+  mockCall.mockClear();
+});
+
+afterEach(async () => {
+  // ensure no on-disk braindb was created
+  const { unlink } = await import("fs/promises");
+  try {
+    await unlink("/tmp/brainbox-test-braindb-debug-schedule.json");
+  } catch {}
+});
+
+describe("runDebugScheduleDaily", () => {
+  test("T1: returns ok result with schedule and availability, uses the supplied personality", async () => {
+    const result = await runDebugScheduleDaily({
+      message: "focus on writing",
+      personality: "test-personality-XYZ",
+    });
+
+    expect(result.ok).toBe(true);
+    if (!result.ok) throw new Error("expected ok");
+
+    expect(result.kind).toBe("daily");
+    expect(result.schedule).toHaveLength(48);
+    expect(result.availability.length).toBeGreaterThan(0);
+    expect(result.dateKey).toMatch(/^\d{4}-\d{2}-\d{2}$/);
+
+    const dailyCall = llmCalls.find(
+      (c) => c.options.jsonSchemaName === "daily-schedule",
+    );
+    expect(dailyCall).toBeDefined();
+    expect(dailyCall!.options.message).toContain("test-personality-XYZ");
+    expect(dailyCall!.options.message).toContain("focus on writing");
+
+    const availCall = llmCalls.find(
+      (c) => c.options.jsonSchemaName === "availability",
+    );
+    expect(availCall).toBeDefined();
+  });
+
+  test("T2: when LLM returns null for daily, returns {ok: false, error}", async () => {
+    mockCall.mockImplementationOnce(async () => null as unknown as never);
+    const result = await runDebugScheduleDaily({
+      message: "",
+      personality: "p",
+    });
+    expect(result.ok).toBe(false);
+    if (result.ok) throw new Error("expected !ok");
+    expect(result.error).toMatch(/Daily schedule generation failed/);
+  });
+});
+
+describe("runDebugScheduleMonthly", () => {
+  test("T3: returns ok result with monthly schedule, uses the supplied personality", async () => {
+    const result = await runDebugScheduleMonthly({
+      message: "study for GRE",
+      personality: "test-personality-ABC",
+    });
+
+    expect(result.ok).toBe(true);
+    if (!result.ok) throw new Error("expected ok");
+
+    expect(result.kind).toBe("monthly");
+    expect(result.schedule).toHaveLength(result.daysInMonth);
+    expect(result.monthKey).toMatch(/^\d{4}-\d{2}$/);
+
+    const call = llmCalls.find(
+      (c) => c.options.jsonSchemaName === "monthly-schedule",
+    );
+    expect(call).toBeDefined();
+    expect(call!.options.message).toContain("test-personality-ABC");
+    expect(call!.options.message).toContain("study for GRE");
+  });
+
+  test("T4: when LLM returns null for monthly, returns {ok: false, error}", async () => {
+    mockCall.mockImplementationOnce(async () => null as unknown as never);
+    const result = await runDebugScheduleMonthly({
+      message: "",
+      personality: "p",
+    });
+    expect(result.ok).toBe(false);
+    if (result.ok) throw new Error("expected !ok");
+    expect(result.error).toMatch(/Monthly schedule generation failed/);
+  });
+});
+
+describe("debug schedule no-disk invariant", () => {
+  test("T5: running a debug schedule does not create a brainbox db file on disk", async () => {
+    const { existsSync } = await import("fs");
+    const { resolve } = await import("path");
+
+    const beforeDb = existsSync(resolve(process.cwd(), "brainbox.db"));
+    const beforeJson = existsSync(resolve(process.cwd(), "brainbox.json"));
+
+    await runDebugScheduleDaily({ message: "m", personality: "p" });
+
+    const afterDb = existsSync(resolve(process.cwd(), "brainbox.db"));
+    const afterJson = existsSync(resolve(process.cwd(), "brainbox.json"));
+
+    expect(beforeDb).toBe(false);
+    expect(beforeJson).toBe(false);
+    expect(afterDb).toBe(false);
+    expect(afterJson).toBe(false);
+  });
+});
diff --git a/src/commands/debug/schedule.ts b/src/commands/debug/schedule.ts
new file mode 100644
index 0000000..a5f7d8d
--- /dev/null
+++ b/src/commands/debug/schedule.ts
@@ -0,0 +1,171 @@
+import type { Command } from "commander";
+import ora from "ora";
+import { Brain } from "@/brain";
+import { logger } from "@/utils/logger";
+import {
+  type Availability,
+  type DailySchedule,
+  type MonthlySchedule,
+  formatDateKey,
+  nextMonth,
+  pad2,
+} from "@/brain/schedule";
+
+export interface ScheduleOptions {
+  message: string;
+  personality: string;
+}
+
+export type DailyRunResult =
+  | {
+      ok: true;
+      kind: "daily";
+      dateKey: string;
+      tomorrow: Date;
+      schedule: DailySchedule;
+      availability: Availability[];
+    }
+  | { ok: false; error: string };
+
+export type MonthlyRunResult =
+  | {
+      ok: true;
+      kind: "monthly";
+      monthKey: string;
+      daysInMonth: number;
+      schedule: MonthlySchedule;
+    }
+  | { ok: false; error: string };
+
+export async function runDebugScheduleDaily(
+  opts: ScheduleOptions,
+): Promise<DailyRunResult> {
+  const today = new Date();
+  const tomorrow = new Date(
+    today.getFullYear(),
+    today.getMonth(),
+    today.getDate() + 1,
+  );
+  const dateKey = formatDateKey(tomorrow);
+
+  const brain = await Brain.createDebug({ personality: opts.personality });
+
+  const scheduleSpinner = ora(
+    `Generating daily schedule for ${dateKey}...`,
+  ).start();
+  const schedule = await brain.createDailySchedule(today, opts.message);
+  if (!schedule) {
+    scheduleSpinner.fail("Daily schedule generation failed");
+    return { ok: false, error: "Daily schedule generation failed" };
+  }
+  scheduleSpinner.succeed(
+    `Daily schedule generated (${schedule.length} slots)`,
+  );
+
+  printSection(
+    `Daily Schedule — ${dateKey} (${tomorrow.toLocaleDateString("en-US", { weekday: "long" })})`,
+  );
+  console.log(JSON.stringify(schedule, null, 2));
+
+  const availSpinner = ora("Deriving availability...").start();
+  const availability = await brain.deriveAvailabilityFromSchedule(schedule);
+  if (!availability) {
+    availSpinner.fail("Availability derivation failed");
+    return { ok: false, error: "Availability derivation failed" };
+  }
+  availSpinner.succeed(
+    `Availability derived (${availability.length} windows)`,
+  );
+
+  printSection(`Availability — ${dateKey}`);
+  console.log(JSON.stringify(availability, null, 2));
+
+  logger.info("Debug run complete. Nothing was written to disk.");
+
+  return {
+    ok: true,
+    kind: "daily",
+    dateKey,
+    tomorrow,
+    schedule,
+    availability,
+  };
+}
+
+export async function runDebugScheduleMonthly(
+  opts: ScheduleOptions,
+): Promise<MonthlyRunResult> {
+  const today = new Date();
+  const next = nextMonth(today);
+  const monthKey = `${next.year}-${pad2(next.month + 1)}`;
+
+  const brain = await Brain.createDebug({ personality: opts.personality });
+
+  const scheduleSpinner = ora(
+    `Generating monthly schedule for ${monthKey} (${next.daysInMonth} days)...`,
+  ).start();
+  const schedule = await brain.createMonthlySchedule(today, opts.message);
+  if (!schedule) {
+    scheduleSpinner.fail("Monthly schedule generation failed");
+    return { ok: false, error: "Monthly schedule generation failed" };
+  }
+  scheduleSpinner.succeed(
+    `Monthly schedule generated (${schedule.length} day summaries)`,
+  );
+
+  printSection(`Monthly Schedule — ${monthKey} (${next.daysInMonth} days)`);
+  console.log(JSON.stringify(schedule, null, 2));
+
+  logger.info(
+    "Debug run complete. Nothing was written to disk. (Availability applies per-day and is not generated for the monthly view.)",
+  );
+
+  return {
+    ok: true,
+    kind: "monthly",
+    monthKey,
+    daysInMonth: next.daysInMonth,
+    schedule,
+  };
+}
+
+export function addScheduleSubcommand(parent: Command): Command {
+  const cmd = parent
+    .command("schedule")
+    .description("Generate a test schedule (no disk writes)");
+
+  cmd.command("daily")
+    .description(
+      "Generate a daily schedule for tomorrow and print schedule + availability",
+    )
+    .requiredOption("-m, --message <text>", "User direction for the schedule")
+    .requiredOption("-p, --personality <text>", "Brain personality to use")
+    .action(async (opts: ScheduleOptions) => {
+      const result = await runDebugScheduleDaily(opts);
+      if (!result.ok) {
+        logger.error(result.error);
+        process.exit(1);
+      }
+    });
+
+  cmd.command("monthly")
+    .description("Generate a monthly schedule for next month and print it")
+    .requiredOption("-m, --message <text>", "User direction for the schedule")
+    .requiredOption("-p, --personality <text>", "Brain personality to use")
+    .action(async (opts: ScheduleOptions) => {
+      const result = await runDebugScheduleMonthly(opts);
+      if (!result.ok) {
+        logger.error(result.error);
+        process.exit(1);
+      }
+    });
+
+  return cmd;
+}
+
+function printSection(title: string): void {
+  const line = "─".repeat(Math.max(40, title.length + 4));
+  console.log(`\n┌${line}┐`);
+  console.log(`│  ${title}`);
+  console.log(`└${line}┘`);
+}
diff --git a/src/commands/index.test.ts b/src/commands/index.test.ts
new file mode 100644
index 0000000..abb6265
--- /dev/null
+++ b/src/commands/index.test.ts
@@ -0,0 +1,50 @@
+import { describe, expect, test } from "bun:test";
+import { Command } from "commander";
+import { registerCommand } from "./index";
+
+describe("registerCommand", () => {
+  test("attaches a subcommand with the given name and description", () => {
+    const program = new Command();
+    const cmd = registerCommand(program, {
+      name: "foo",
+      description: "Foo command",
+    });
+    expect(cmd).toBeDefined();
+    expect(cmd.name()).toBe("foo");
+    expect(cmd.description()).toBe("Foo command");
+  });
+
+  test("returns the newly-created subcommand", () => {
+    const program = new Command();
+    const cmd = registerCommand(program, {
+      name: "bar",
+      description: "Bar command",
+    });
+    expect(program.commands.find((c) => c.name() === "bar")).toBe(cmd);
+  });
+
+  test("invokes the configure callback with the new subcommand", () => {
+    const program = new Command();
+    let received: Command | undefined;
+    registerCommand(program, {
+      name: "baz",
+      description: "Baz command",
+      configure: (cmd) => {
+        received = cmd;
+        cmd.option("-x, --xtra <value>", "extra");
+      },
+    });
+    expect(received).toBeDefined();
+    expect(received!.name()).toBe("baz");
+    const baz = program.commands.find((c) => c.name() === "baz");
+    expect(baz?.options.find((o) => o.long === "--xtra")).toBeDefined();
+  });
+
+  test("omitting configure is allowed and does not throw", () => {
+    const program = new Command();
+    expect(() =>
+      registerCommand(program, { name: "qux", description: "Qux" }),
+    ).not.toThrow();
+    expect(program.commands.find((c) => c.name() === "qux")).toBeDefined();
+  });
+});
diff --git a/src/commands/index.ts b/src/commands/index.ts
new file mode 100644
index 0000000..1ea0559
--- /dev/null
+++ b/src/commands/index.ts
@@ -0,0 +1,16 @@
+import type { Command } from "commander";
+
+export interface CommandConfig {
+  name: string;
+  description: string;
+  configure?: (cmd: Command) => void;
+}
+
+export function registerCommand(
+  program: Command,
+  config: CommandConfig,
+): Command {
+  const cmd = program.command(config.name).description(config.description);
+  config.configure?.(cmd);
+  return cmd;
+}
diff --git a/src/commands/run.ts b/src/commands/run.ts
index 418a302..3845ed8 100644
--- a/src/commands/run.ts
+++ b/src/commands/run.ts
@@ -1,3 +1,11 @@
-// Run brain
+import type { Command } from "commander";
+import { registerCommand } from "@/commands";
 
 export async function run() {}
+
+export function register(program: Command): Command {
+  return registerCommand(program, {
+    name: "run",
+    description: "Run BrainBox",
+  }).action(run);
+}
diff --git a/src/index.ts b/src/index.ts
index 507513b..2805cb9 100755
--- a/src/index.ts
+++ b/src/index.ts
@@ -4,8 +4,9 @@ import { readFileSync } from "fs";
 import { fileURLToPath } from "url";
 import { dirname, join } from "path";
 import { logger } from "@/utils/logger";
-import { run } from "@/commands/run";
-import { brain } from "@/commands/brain";
+import { register as run } from "@/commands/run";
+import { register as brain } from "@/commands/brain";
+import { register as debug } from "@/commands/debug";
 
 const __filename = fileURLToPath(import.meta.url);
 const __dirname = dirname(__filename);
@@ -32,8 +33,9 @@ program
     outputError: (str) => logger.error(str.replace("error: ", "")),
   });
 
-program.command("run").description("Run BrainBox").action(run);
-program.command("brain").description("Manage brains").action(brain);
+run(program);
+brain(program);
+debug(program);
 
 program.on("command:*", () => {
   logger.error(`Unknown command: ${program.args.join(" ")}`);