diff --git a/src/cli/commands/baseline.ts b/src/cli/commands/baseline.ts
index 556f20c..e26b0cf 100644
--- a/src/cli/commands/baseline.ts
+++ b/src/cli/commands/baseline.ts
@@ -11,6 +11,10 @@ import type { CliContext } from '../index.js';
 
 import { BaselineStorageService } from '../../services/baseline-storage.js';
 import { createTaskId } from '../../types/index.js';
+import {
+  formatDuration,
+  formatOpsPerSecond,
+} from '../../utils/reporter-utils.js';
 
 /**
  * Options for baseline analyze command
@@ -62,38 +66,6 @@ interface BaselineShowOptions extends BaselineBaseOptions {
   name: string;
 }
 
-/**
- * Format duration in human-readable format
- */
-const formatDuration = (nanoseconds: number): string => {
-  if (nanoseconds < 1000) {
-    return `${nanoseconds.toFixed(2)}ns`;
-  }
-  if (nanoseconds < 1_000_000) {
-    return `${(nanoseconds / 1000).toFixed(2)}μs`;
-  }
-  if (nanoseconds < 1_000_000_000) {
-    return `${(nanoseconds / 1_000_000).toFixed(2)}ms`;
-  }
-  return `${(nanoseconds / 1_000_000_000).toFixed(2)}s`;
-};
-
-/**
- * Format operations per second
- */
-const formatOpsPerSec = (ops: number): string => {
-  if (ops < 1000) {
-    return `${ops.toFixed(2)} ops/sec`;
-  }
-  if (ops < 1_000_000) {
-    return `${(ops / 1000).toFixed(2)}K ops/sec`;
-  }
-  if (ops < 1_000_000_000) {
-    return `${(ops / 1_000_000).toFixed(2)}M ops/sec`;
-  }
-  return `${(ops / 1_000_000_000).toFixed(2)}B ops/sec`;
-};
-
 /**
  * Format date in readable format
  */
@@ -337,7 +309,9 @@ export const handleShowCommand = async (
         for (const [taskId, data] of tasks) {
           console.log(`    ${taskId}`);
           console.log(`      Mean:    ${formatDuration(data.mean)}`);
-          console.log(`      Ops/sec: ${formatOpsPerSec(data.opsPerSecond)}`);
+          console.log(
+            `      Ops/sec: ${formatOpsPerSecond(data.opsPerSecond)}`,
+          );
           if (data.p99) {
             console.log(`      P99:     ${formatDuration(data.p99)}`);
           }
diff --git a/src/cli/commands/history.ts b/src/cli/commands/history.ts
index 827eb5c..a20a714 100644
--- a/src/cli/commands/history.ts
+++ b/src/cli/commands/history.ts
@@ -22,6 +22,7 @@ import {
   parseDate,
 } from '../../services/history/query.js';
 import { TrendAnalysisService } from '../../services/history/trend-analysis.js';
+import { formatBytes } from '../../utils/reporter-utils.js';
 
 /**
  * Base options shared by all history subcommands
@@ -94,22 +95,6 @@ interface HistoryTrendsOptions extends BaseHistoryOptions {
   until?: string | undefined;
 }
 
-/**
- * Format bytes in human-readable format
- */
-const formatBytes = (bytes: number): string => {
-  const units = ['B', 'KB', 'MB', 'GB'];
-  let size = bytes;
-  let unitIndex = 0;
-
-  while (size >= 1024 && unitIndex < units.length - 1) {
-    size /= 1024;
-    unitIndex++;
-  }
-
-  return `${size.toFixed(1)} ${units[unitIndex]}`;
-};
-
 /**
  * Resolve a partial run ID to a full ID by checking prefix match
  *
diff --git a/src/cli/handlers.ts b/src/cli/handlers.ts
index e0d7507..f909827 100644
--- a/src/cli/handlers.ts
+++ b/src/cli/handlers.ts
@@ -8,8 +8,8 @@
  */
 
 import { ABORT_TIMEOUT, ExitCodes } from '../constants.js';
-import { isError } from '../errors/base.js';
 import { isModestBenchError, UnknownError } from '../errors/index.js';
+import { isError } from '../utils/type-guards.js';
 
 /**
  * Handle process signals gracefully
@@ -65,5 +65,12 @@ export const setupSignalHandlers = (abortController: AbortController): void => {
  * @returns The exit code
  */
 const computeExitCode = (signal: NodeJS.Signals): number => {
-  return 128 + (signal === 'SIGINT' ? 2 : signal === 'SIGQUIT' ? 3 : 15);
+  switch (signal) {
+    case 'SIGINT':
+      return 130; // 128 + 2
+    case 'SIGQUIT':
+      return 131; // 128 + 3
+    default:
+      return 143; // 128 + 15 (SIGTERM)
+  }
 };
diff --git a/src/errors/base.ts b/src/errors/base.ts
index 8020b7f..6cbb599 100644
--- a/src/errors/base.ts
+++ b/src/errors/base.ts
@@ -6,6 +6,7 @@
  */
 
 import { SITE_URL } from '../constants.js';
+import { isError } from '../utils/type-guards.js';
 
 /**
  * Base URL for error documentation
@@ -150,13 +151,3 @@ export const isModestBenchError = (
     (error as { code: string }).code.startsWith('ERR_MB_')
   );
 };
-
-/**
- * Type guard to check if an error is a standard Error
- *
- * @param error - The error to check
- * @returns `true` if the error is an `Error`
- */
-export const isError = (error: unknown): error is Error => {
-  return error instanceof Error;
-};