Curtail is Your AI Integration Partner
We Provide Guardrails to Deliver Safer,
Faster & Less Expensive AI-Generated Code
Proven in the Wild
What if your tests could find vulnerabilities they weren't looking for?
A widely-used open-source platform shipped a password hash disclosure bug for 7 years. Standard tests passed every day. ReGrade caught it on the first replay — without knowing the vulnerability existed.
example ReGrade merge request comments
7 Years
Undetected
3,730 → 2
Noise to Signal
Zero
Security Tests
Supercharge your AI coding agent
We benchmarked Claude Code with and without ReGrade’s MCP tools on the same codebase, the same bugs, and the same AI model. The results speak for themselves.
3.2×
Faster
44%
Less Costly
71%
Fewer Tokens
96%
Root-Cause Quality
of deltas traced to root cause
Ghost CMS v2.2.2 → v2.2.3 · Claude Opus 4.6 · 72 Requests · 3,328 Deltas
Ghost CMS API benchmark — 72 requests, 3,328 deltas. Advantages compound at scale.
We Find and Fix Bugs to Make Your AI Coding Agent Work Better
AI-generated code creates hallucinations and unasked-for changes, all while insisting the code is correct. ReGrade uses field-level analysis to catch these errors and feeds critical guardrail information back to the AI Coding Agent for better solutions.
Powered by NCAST
NCAST (Network Comparison Application Security Testing) is Curtail's patented technology. It sends identical requests to both current and candidate software versions, compares responses at the field level, and identifies unexpected behavioral differences — no CVEs, prior knowledge, or source code access needed.
No Prior Knowledge Required
No CVEs, vulnerability databases, or source code access needed. NCAST detects behavioral differences purely by comparing traffic between versions.
Record and Replay
Capture any traffic — test, production, synthetic — and replay it against candidate versions. ReGrade doesn't care where the traffic comes from. The more the better.
Zero Code Changes
Operates at the network layer. No SDK, no agents, no instrumentation in your application code.
Handles Real-World Complexity
Dynamic IDs, session tokens, expected noise — ReGrade handles the practical obstacles that break naive traffic comparison. Noise reduction profiles, ID mapping, JSON-aware structural comparison, and AI-powered pattern analysis mean analysis just works on real traffic.
Capabilities
Preview Changes to Prevent Costly Rollbacks
Replay real traffic against any code change — AI-generated or human-written — before it ships. ReGrade provides deterministic truth that grounds AI Coding Agent outputs and catches regressions that unit tests miss.
Pinpoint Software Flaws
ReGrade finds behavioral changes introduced by developers or AI agents alike — misconfigurations, broken integrations, undocumented API shifts, and performance degradations — using deterministic field-level comparison, not probabilistic guesswork.
Behavior Observability
ReGrade maps exactly where code diverges from expected behavior and feeds that actionable detail back to the AI Coding Agent or developer for precise fixes — cutting wasted tokens and eliminating trial-and-error iterations.
Shorten DevOps Cycles
ReGrade plugs into your CI/CD pipeline to validate every commit, whether from a human or an AI agent. MCP integration lets AI agents self-correct in seconds, saving hours of manual review and thousands of AI tokens per iteration.
Zero-Day Vulnerabilities
Both human developers and AI coding agents can silently introduce exploitable flaws. ReGrade's deterministic field-level comparison catches behavioral anomalies that probabilistic scanners miss — before attackers find them.
Performance Regression Detection
Compare P95 and P99 response times across versions. ReGrade surfaces latency regressions before they reach production — not just functional bugs, but performance shifts that SREs care about.
Built into your AI coding workflow
Why Curtail's ReGrade?
Implicit Testing
Every API call becomes a test case — no test scripts to write or maintain.
Production-Grade Confidence
Test with real traffic patterns, not synthetic data.
Patented NCAST Technology
Built on NCAST (Network Comparison Application Security Testing) — field-level analysis that works with any traffic source, requires no code changes, and handles encrypted traffic transparently.
Partnerships
Get the guardrails you need for safe & accurate AI code
See how ReGrade catches errors in AI-generated code and feeds fixes back to the AI Coding Agent.