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AI Red Teaming: How to Test an LLM App Before Attackers Do

November 4, 2026
AI Red Teaming: How to Test an LLM App Before Attackers Do

AI red teaming is structured, adversarial testing of an AI system. You try to make it fail, leak data or misbehave before a real attacker or an unlucky customer does. It covers more than the model: prompts, guardrails, data pipelines, APIs and every tool the model can call. If you ship an LLM feature in a B2B product, it is one of the cheapest ways to find out what will embarrass you in production.

I'm Hanad, a senior engineer who builds AI features and MVPs for founders at a fixed price. This guide is how I think about red teaming for a small product team: what it is, what to test, how a round runs, and where it stops being useful.

Hanad Kubat
Build LLM Features With Care
Hanad builds AI features and working software for founders, with fixed scope and code ownership from the first commit.
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Key Takeaways

  • AI red teaming means attacking your own AI system on purpose to find security, safety and trust failures before launch, then fixing them and testing again.
  • Test the whole system, not just the model. Most serious findings come from the connections: retrieved documents, tools, APIs and permissions.
  • Start with a threat model. It defines what "harmful" means for your product and keeps the exercise from becoming random prompt poking.
  • Mix automated attack tooling with human creativity, and treat red teaming as a loop that repeats after every significant change.
  • Architecture beats clever filters. Limit what the model can do, so a successful attack has little to steal or break.

Table of Contents

What AI red teaming actually is

Microsoft describes red teaming for generative AI as a structured approach that combines human expertise with automation to uncover vulnerabilities and risks in AI systems, with a focus on safety, security and trust. Microsoft's guidance on planning red teaming for LLMs also calls it a best practice for responsible development, because the findings feed systematic measurement and show whether your mitigations work.

The OWASP GenAI Red Teaming Guide lists the kinds of problems it targets: prompt injection, toxic outputs and hallucinations, among others. OWASP's guide frames the practice as simulating adversarial behavior to expose weaknesses across security, safety and trust at once.

In plain terms, you play the attacker, or the careless user, or the user who simply asks something nobody planned for. You write down what breaks. Then someone fixes it and you run the same attacks again.

Two other phrases mean nearly the same thing. "LLM red teaming" is the version aimed at language-model applications. "AI adversarial testing" is the research-flavored name for deliberately feeding a system hostile or tricky inputs. The method is the same in all three cases.

What AI red teaming actually is

The three kinds of risk

Security. Can an attacker make the system reveal secrets, run an action it should not, or pull private data out? Prompt injection is the classic route. I wrote about the architectural side in my piece on prompt injection defense.

Safety. Will the system produce content that is harmful, biased or prohibited? IBM Research describes red teaming as provoking a model into prohibited behavior or surfacing unknown biases, and then using those findings to build new instruction data for re-alignment. Read their overview of red teaming for generative AI for the model-builder's view.

Trust. Does it make things up, contradict your documentation or give confident wrong answers? For a B2B product, a hallucinated contract term or invented compliance claim is a trust failure even if nobody "attacked" anything. Retrieval alone does not solve this, which I cover in reducing AI hallucinations in production.

Security safety and trust risks in LLM apps

How it differs from traditional red teaming and normal evaluation

Founders often hear "red team" and picture a penetration test. The two overlap, but they are not the same job.

Researchers at Georgetown's Center for Security and Emerging Technology point out that traditional cybersecurity red teaming focuses on network hacking and infrastructure infiltration. Prompt-based red teaming targets interactions with the language model. They address different risks and call for different expertise, so the CSET analysis of AI red-teaming argues the terms should be kept apart.

The difference from ordinary evaluation matters too. A benchmark runs a fixed set of questions and gives you a score. Red teaming pushes beyond static model-level benchmarks by emulating real-world, context-dependent attacks against complete systems, a point made in the paper Lessons From Red Teaming 100 Generative AI Products.

The U.S. Cybersecurity and Infrastructure Security Agency adds a useful framing. It treats AI red teaming as a subset of testing, evaluation, verification and validation, and says AI systems are software systems that belong inside established software testing practice. Read the CISA article on applying software TEVV to AI if you need a government-grade reference for your security questionnaire.

That last point is practical. Your AI feature is still a web app with authentication, a database and an API. The usual disciplines still apply, and the same thinking runs through vibe coding best practices for controlled AI builds, where speed only works when testing keeps pace.

Traditional red teamStandard AI evaluationAI red teaming
Main targetNetworks, infrastructure, peopleModel or feature qualityThe full AI system under attack
Typical inputExploits, phishing, lateral movementFixed test setsAdversarial prompts, poisoned content, tool abuse
OutputAccess gained, paths foundScores and regression checksReproducible failures with severity
Question answeredCan they get in?Does it work well?Can it be made to fail, and how badly?

What to test: the whole system

The model is the most visible part of an AI product and often not the weakest. OWASP's guide says a red team should look at the base model, the guardrails and prompt templates, the supporting infrastructure and data pipelines, and the runtime interactions between the model, users and any connected APIs or agents. See the OWASP GenAI Red Teaming Guide for the full breakdown.

The OWASP AI Exchange recommends combining conventional pentesting, such as attacking databases, networks and the environment, with specialized AI input attacks like prompt injection. Its AI security testing page is a good checklist anchor.

For a typical B2B SaaS feature, I split the scope into five layers:

  1. System prompt and templates. Can a user extract or override them?
  2. Retrieval and documents. Can content from an uploaded file, web page or email carry instructions the model obeys?
  3. Tools and APIs. What can the model do on a user's behalf, and with whose permissions?
  4. Data handling. What personal or confidential data reaches the prompt, logs and third-party providers? My notes on keeping raw PII out of prompts go deeper.
  5. Output handling. Does your code trust model output, for example rendering it as HTML or passing it to a database query?

If your product browses the web or automates actions, indirect injection deserves extra attention. This write-up on reducing prompt injection risk in web automation covers the browsing side of the problem.

A concrete example

CSET's Evelyn Yee gives a clear scenario: an enterprise AI assistant that can read email. The red team tries to manipulate it with malicious emails so it sends private company data, such as financial or customer information, to an attacker. The CSET piece on red-teaming design uses this to show why the threat model matters.

Notice what is being tested. Nobody is trying to make the model say a rude word. The question is whether untrusted text from an inbox can steer an assistant that holds real permissions. That is a system problem, and a better system prompt will not fully fix it. Limiting what the assistant can send, and to whom, will.

How a red-teaming round works

The process is iterative. According to the Frontier Model Forum's overview of AI red teaming, results set the priorities for measurement and mitigations at scale, and then the evaluations are rerun to see whether the mitigations worked.

Here is the sequence I use on a small product.

1. Write the threat model

CSET describes the threat model as the core design feature of a red-teaming exercise: it bounds the scope and defines what counts as harmful in a specific context. Write it down in a page:

  • What does the system do, and for whom?
  • What assets matter: customer data, API keys, money movement, reputation?
  • Who are the adversaries: a curious customer, a competitor, a malicious third party whose content your system reads?
  • What would a bad outcome look like for your business?

A legal-tech tool and a recipe app have different answers, so they should have different test plans.

2. Build the attack list

Turn the threat model into test cases. Group them by category (prompt injection, data leakage, tool abuse, harmful content, hallucination on critical facts) and write what "failure" means for each. Stanford's AI measurement textbook recommends structured red teaming with test specifications, categories, difficulty targets and standardized scoring rubrics. Its chapter on application is worth reading if you want rigor.

3. Attack manually first

Spend a few hours as a human. Humans find the strange failures: the odd language switch, the polite social-engineering framing, the multi-turn setup. The Stanford text notes that unstructured red teaming relies on human creativity to find unexpected failure modes, but lacks the systematic coverage needed for standardized measurement. That is why you do it first and then structure what you learn.

4. Scale with automation

Automated tools generate many attack variants, run them against your endpoint and grade the responses. The tool list in the next section covers this.

5. Triage by severity and exploitability

Not every failure matters equally. A jailbreak that makes the bot write a poem in a pirate voice is low. A prompt that makes it return another tenant's records is a launch blocker. Rank by impact on the assets in your threat model.

6. Fix, then retest

Fix at the right layer. Permissions and architecture first, then input and output controls, then prompt wording. After that, rerun the same attacks and keep them as regression tests. My article on AI evaluation metrics that stop regressions explains how to wire this into a routine.

Tools and metrics, and where they fall short

A survey of building safe GenAI applications by Alberto Purpura lists the toolbox: frameworks such as Garak, automated attack generators and LLM-as-judge systems for scoring responses. The same paper notes the limits: judges can struggle with domain-specific judgments, and inference can take a long time. Details are in the arXiv overview.

The paper also names two common metrics. Attack Success Rate is the share of attempts that got the system to misbehave. Attack Effectiveness Rate looks at collective responses across safety and helpfulness. Track them over time, not as one-off scores, so you can tell whether a change helped.

Two cautions from the research shape how I use tools:

  • An LLM grading another LLM is a tool, not an oracle. Spot-check its verdicts by hand, especially in a specialized field such as medicine or law.
  • IBM Research observes that red-team models focused only on prompts likely to trigger toxic replies may miss rarer, more serious failure modes, which is why novelty-seeking attack generation exists. Variety in your attack set matters more than volume. The IBM Research overview explains the idea.

If your product uses retrieval, pair red teaming with a small, curated question set that checks answer quality. My RAG evaluation playbook covers how to build one with 50 to 150 golden queries.

Trade-offs to plan for

Red teaming is not a one-time certificate. A few realities to plan around:

  • Coverage versus creativity. Manual testing finds surprises, automation finds breadth. OWASP's recommendation is to combine automated tooling with human expertise and cross-functional collaboration for the more nuanced risks.
  • It decays. Models update, prompts change and new tools get connected. A mature function, per OWASP, involves multidisciplinary teams and iterative processes that adapt to evolving threats. A small team can do the same in miniature: rerun the suite on every significant change.
  • Scope creep. Without a threat model, a red-team exercise turns into endless prompt tinkering. Keep it tied to the assets you wrote down.
  • Third parties. If your feature depends on an external model provider or vendor, their behavior is part of your risk. A structured AI vendor risk assessment belongs next to your red-team plan.

Perspective

I build AI features for small product teams, and the same pattern shows up again and again: the model is rarely where the damage happens. The damage happens where an overly trusting integration meets a model that can be talked into things.

So my view is that red teaming should begin before the first line of feature code. I draw the threat model while I design the architecture: which data the model sees, which actions it can take, and what happens when it is wrong. Then the attack tests I write are checks against decisions I already made, not a panic exercise the week before launch.

I also think a small product does not need a large security program to do this well. It needs a clear scope, a few hundred well-chosen test cases, a person who actually reads the failures, and a habit of rerunning them. I work on fixed price and fixed scope, so I put the evaluation and attack suite inside the build and hand it over with the code. You own it from the first commit, and the next developer can keep running it.

My stack is deliberately boring and widely known for the same reason. Security work only survives if the people who come after me can read it.

Hanad Kubat

A practical plan for a team of one to five

If you do not have a security department, this is a realistic sequence before you put an LLM feature in front of paying customers:

  1. Day 1: scope. Draft the one-page threat model. List assets, adversaries and the actions your model can trigger.
  2. Day 2: reduce power. Remove permissions the feature does not need. Separate read access from write access. Require confirmation for irreversible actions. This shrinks the damage of every later finding.
  3. Days 3 to 4: manual attacks. Spend an afternoon attacking your own feature, ideally with someone who did not build it. Log every failure with the exact input.
  4. Day 5: automate. Run an open-source attack framework against your staging endpoint and combine the results with your manual cases.
  5. Following week: fix and retest. Fix by severity. Add every confirmed failure to a regression suite.
  6. Rollout. Release in stages and watch for new failure types in real traffic. My phased AI feature rollout plan and five guardrails for SaaS founders lay out how.

If you want a broader review that goes beyond attacks, my AI audit checklist is something a team can run on its own. For EU-facing products, the privacy documentation side is covered in my AI DPIA template.

Work with me on the build

I build the first real version of software products and AI features as a single senior engineer: fixed price, fixed scope, usually two to four weeks, and you own the code from the first commit. Builds start from €12,000, and the price is possible because there is no agency overhead, no project-manager layer and no offshore markup. If you have a prototype built in an AI app builder that now needs hardening, or an AI feature you want shipped with testing built in, see my app development offer and tell me what you have. If an off-the-shelf tool fits your case better, I will say so.

FAQ

What is an example of red teaming in AI?

A standard example is an AI assistant that reads company email. The tester sends it a malicious message designed to make it forward financial or customer data to an outside address. If the assistant complies, you have found a real vulnerability, and the fix is usually to limit its permissions and outbound actions.

Is AI red teaming the same as penetration testing?

No, though they complement each other. Penetration testing targets networks, servers and applications. AI red teaming adds attacks on model behavior, such as prompt injection and jailbreaks, and on how the model connects to tools and data. OWASP recommends combining both for AI systems.

Can automated tools replace human red teamers?

Not fully. Automation gives breadth and repeatability, and it is how you run regression checks. Humans find unexpected failure modes and judge domain-specific harm. Guidance from OWASP recommends combining the two.

How often should I red team an LLM application?

Run a full round before launch and whenever you change the model, the system prompt, the retrieval sources or the tools the model can call. Keep a regression suite of past failures that runs on every release. Treat it as a loop, not a one-time project.

Sources