AI Coding Cost Per Security Audit: The Token Math of Automated Pentesting
By Eric Bush · July 29, 2026 · 5 min read
A professional penetration test costs $5,000-$50,000. An AI-powered security scan costs $12-$35. The ROI math is obvious — but how many tokens does it actually take?
Let's break down the token economics of having an AI agent audit your code for security vulnerabilities, from first read to fix generation.
The Three Phases of an AI Security Audit
A complete automated security scan has three token-heavy phases:
Phase 1: Code Reading (Input-Heavy)
The agent reads your entire codebase to build a mental model of data flows, trust boundaries, and attack surface. For a 10K LOC app:
- ~50K tokens of source code (5 tokens/line avg)
- ~30K tokens of system prompt + security rules
- Multiple passes over critical files: auth, API routes, data access
- Total input: ~1.5M tokens
Phase 2: Vulnerability Analysis (Reasoning-Heavy)
The model reasons about attack vectors, data flows, and edge cases. This generates significant output:
- Context from Phase 1 carried forward: ~500K input tokens
- Structured vulnerability report generation: ~200K output tokens
- Cross-referencing findings across files: ~300K additional input
- Total: ~800K input + 200K output
Phase 3: Fix Generation (Output-Heavy)
For confirmed vulnerabilities, the agent generates patches:
- Context per fix: ~100K input tokens (file + surrounding code)
- Generated fix code: ~50K output tokens per major vulnerability
- Assuming 3-5 findings needing fixes
- Total: ~500K input + 200K output
Total Cost by Model
Grand total for a 10K LOC app: ~2.8M input tokens + ~600K output tokens
| Model | Input Cost | Output Cost | Total |
|---|---|---|---|
| Claude Opus 5 ($5/$25) | $14.00 | $15.00 | $29.00 |
| Claude Sonnet 5 ($2/$10) | $5.60 | $6.00 | $11.60 |
| GPT-5.6 Sol ($5/$30) | $14.00 | $18.00 | $32.00 |
| Claude Fable 5 ($10/$50) | $28.00 | $30.00 | $58.00 |
ROI: AI Scan vs. Human Pentest
| Approach | Cost | Frequency | Annual Cost |
|---|---|---|---|
| AI scan (Opus 5), weekly | $29/scan | 52x/year | $1,508 |
| AI scan (Sonnet 5), daily | $12/scan | 260x/year | $3,016 |
| Human pentest, quarterly | $10,000/test | 4x/year | $40,000 |
Recommended Strategy
The optimal approach layers both AI and human auditing:
- Per-PR: lightweight Sonnet 5 scan (~$3-5 per scan, focused on changed files)
- Weekly: full Opus 5 audit (~$29, comprehensive codebase scan)
- Quarterly: human pentest ($5,000-15,000, finds business logic flaws AI misses)
Total annual cost: ~$3,000-5,000 in AI tokens + one quarterly human pentest. Compare to relying solely on quarterly human testing: continuous AI scanning catches 80% of issues within days instead of waiting 3 months.
Budget security tokens as a fixed percentage of your AI coding spend. We recommend 15-20%. Use our AI Cost Calculator to estimate your project's total token consumption.
Want to calculate exact costs for your project?
Frequently Asked Questions
How much does an AI security audit cost in tokens?
A full security scan of a 10K-line application costs approximately 2.8M input + 600K output tokens — about $29 with Claude Opus 5 or $12 with Sonnet 5.
Can AI replace human penetration testing?
Not entirely. AI scans catch common vulnerability patterns (access control, injection, XSS) but miss complex business logic flaws. The recommended approach is continuous AI scanning plus quarterly human pentests.
How often should I run AI security scans?
Lightweight scans (Sonnet 5, $3-5) on every PR. Full comprehensive scans (Opus 5, $29) weekly. This catches most issues within days of introduction rather than waiting for quarterly audits.
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