diff --git a/packages/cli/src/commands/scale.test.ts b/packages/cli/src/commands/scale.test.ts
index e4c3b6bb..ccf5c722 100644
--- a/packages/cli/src/commands/scale.test.ts
+++ b/packages/cli/src/commands/scale.test.ts
@@ -11,6 +11,9 @@ import {
   saveFleet,
   loadRollouts,
   saveRollouts,
+  parsePositiveSafeInteger,
+  parseNonNegativeSafeInteger,
+  parsePositiveFiniteNumber,
 } from './scale.js';
 
 // Helper to create a temp dir and override CREDS_FILE path
@@ -28,6 +31,30 @@ afterEach(() => {
   }
 });
 
+describe('scale numeric option parsers', () => {
+  it('accepts safe integer counts and rejects invalid count values', () => {
+    expect(parsePositiveSafeInteger('3')).toBe(3);
+    for (const invalid of ['nope', '1.5', '0', '-1', 'Infinity', '9007199254740992']) {
+      expect(() => parsePositiveSafeInteger(invalid)).toThrow('positive safe integer');
+    }
+  });
+
+  it('allows zero only for non-negative safe integer options', () => {
+    expect(parseNonNegativeSafeInteger('0')).toBe(0);
+    expect(parseNonNegativeSafeInteger('4')).toBe(4);
+    for (const invalid of ['-1', '1.5', 'NaN', 'Infinity']) {
+      expect(() => parseNonNegativeSafeInteger(invalid)).toThrow('non-negative safe integer');
+    }
+  });
+
+  it('accepts positive finite prices and rejects non-finite or non-positive values', () => {
+    expect(parsePositiveFiniteNumber('1.25')).toBe(1.25);
+    for (const invalid of ['nope', '0', '-1', 'Infinity', '-Infinity']) {
+      expect(() => parsePositiveFiniteNumber(invalid)).toThrow('positive finite number');
+    }
+  });
+});
+
 // ---------------------------------------------------------------------------
 // getNextId
 // ---------------------------------------------------------------------------
diff --git a/packages/cli/src/commands/scale.ts b/packages/cli/src/commands/scale.ts
index 5b433a10..7d2e52e1 100644
--- a/packages/cli/src/commands/scale.ts
+++ b/packages/cli/src/commands/scale.ts
@@ -1,4 +1,4 @@
-import { Command } from 'commander';
+import { Command, InvalidArgumentError } from 'commander';
 import kleur from 'kleur';
 import { readFileSync, writeFileSync, existsSync, mkdirSync } from 'node:fs';
 import { homedir } from 'node:os';
@@ -12,6 +12,30 @@ import { deployCmd } from './deploy.js';
 const CREDS_FILE = join(homedir(), '.sh1pt', 'credentials.json');
 const ROLLOUTS_FILE = join(homedir(), '.sh1pt', 'rollouts.json');
 
+export function parsePositiveSafeInteger(value: string): number {
+  const parsed = Number(value);
+  if (!Number.isSafeInteger(parsed) || parsed < 1) {
+    throw new InvalidArgumentError('must be a positive safe integer');
+  }
+  return parsed;
+}
+
+export function parseNonNegativeSafeInteger(value: string): number {
+  const parsed = Number(value);
+  if (!Number.isSafeInteger(parsed) || parsed < 0) {
+    throw new InvalidArgumentError('must be a non-negative safe integer');
+  }
+  return parsed;
+}
+
+export function parsePositiveFiniteNumber(value: string): number {
+  const parsed = Number(value);
+  if (!Number.isFinite(parsed) || parsed <= 0) {
+    throw new InvalidArgumentError('must be a positive finite number');
+  }
+  return parsed;
+}
+
 export interface FleetEntry {
   id: string;
   provider: string;
@@ -165,9 +189,9 @@ scaleCmd.addCommand(deployCmd);
 scaleCmd
   .command('up')
   .description('Buy more instances of the current SKU (via sh1pt deploy under the hood)')
-  .option('--instances <n>', 'how many to add', Number, 1)
+  .option('--instances <n>', 'how many to add', parsePositiveSafeInteger, 1)
   .option('--provider <id>', 'which cloud provider to add to (default: same as existing fleet, or first in pricing table)')
-  .option('--max-hourly-price <usd>', 'abort if the new instances would push above this total/hr', Number)
+  .option('--max-hourly-price <usd>', 'abort if the new instances would push above this total/hr', parsePositiveFiniteNumber)
   .option('--dry-run', 'show the plan without modifying state')
   .action((opts: {
     instances: number;
@@ -262,7 +286,7 @@ scaleCmd
 scaleCmd
   .command('down')
   .description('Tear down instances (cheapest / least-healthy first)')
-  .option('--instances <n>', 'number of instances to destroy', Number, 1)
+  .option('--instances <n>', 'number of instances to destroy', parsePositiveSafeInteger, 1)
   .option('--provider <id>', 'only remove instances from this cloud provider')
   .option('--dry-run', 'show the plan without modifying state')
   .option('--json', 'machine-readable output')
@@ -371,10 +395,10 @@ scaleCmd
 scaleCmd
   .command('auto')
   .description('Set auto-scale rules (sh1pt cloud polls metrics and runs scale up/down on your behalf)')
-  .option('--min <n>', 'minimum instances', Number, 1)
-  .option('--max <n>', 'maximum instances', Number, 10)
-  .option('--target-cpu <percent>', 'target CPU utilization to maintain', Number, 70)
-  .option('--cooldown <seconds>', 'minimum time between scale events', Number, 300)
+  .option('--min <n>', 'minimum instances', parseNonNegativeSafeInteger, 1)
+  .option('--max <n>', 'maximum instances', parsePositiveSafeInteger, 10)
+  .option('--target-cpu <percent>', 'target CPU utilization to maintain', parsePositiveSafeInteger, 70)
+  .option('--cooldown <seconds>', 'minimum time between scale events', parsePositiveSafeInteger, 300)
   .option('--status', 'show current auto-scale rules')
   .option('--dry-run', 'show the rules without saving')
   .option('--json', 'machine-readable output')
@@ -497,7 +521,7 @@ scaleCmd
   .description('Wire round-robin DNS so traffic spreads across the fleet')
   .requiredOption('--provider <id>', 'dns-porkbun | dns-cloudflare')
   .requiredOption('--domain <fqdn>', 'e.g. api.example.com')
-  .option('--ttl <seconds>', 'TTL for DNS records', Number, 60)
+  .option('--ttl <seconds>', 'TTL for DNS records', parsePositiveSafeInteger, 60)
   .option('--proxied', 'cloudflare only — route through the CF edge (orange cloud)')
   .option('--dry-run', 'show the DNS records that would be created/updated')
   .option('--json', 'machine-readable output')
@@ -609,7 +633,7 @@ scaleCmd
   .description('Stage a new version across the fleet (canary / blue-green / rolling)')
   .requiredOption('--version <id>', 'version identifier to deploy (e.g. v2.1.0)')
   .option('--strategy <kind>', 'canary | blue-green | rolling', 'canary')
-  .option('--percent <n>', 'canary only — start at N% of traffic', Number, 5)
+  .option('--percent <n>', 'canary only — start at N% of traffic', parsePositiveSafeInteger, 5)
   .option('--dry-run', 'show the plan without modifying state')
   .option('--status', 'show active rollouts and their state')
   .option('--rollback <id>', 'roll back a previously completed rollout by ID')