DEV Community

Leena Malhotra
Leena Malhotra

Posted on

I Tried Building an AI Agent and It Failed Halfway Through. Here's Why

I spent three weeks building an AI agent to automate our code review process. The demo was impressive. It could parse pull requests, identify potential bugs, suggest improvements, and even comment directly on GitHub. My team was excited. Leadership was impressed. I was convinced this was going to save us dozens of hours every week.

Then I deployed it to production.

Within two days, developers were muting its notifications. Within a week, they were ignoring it entirely. Within two weeks, I shut it down. The agent didn't fail because of bugs or performance issues. It failed because I fundamentally misunderstood what makes AI agents actually useful in real workflows.

Here's what I learned from building an AI agent that nobody wanted to use.

The Fantasy vs. The Reality

The fantasy of AI agents is seductive: autonomous systems that handle complex workflows without human intervention. You describe what you want, the agent figures out how to do it, and you wake up to completed work. It's the developer's dream—automation that actually understands context.

The reality is that most AI agents fail not because they're technically insufficient, but because they're built around the wrong assumptions.

Assumption 1: "If it works in demos, it works in production."

My code review agent worked flawlessly in demos because I tested it on carefully selected pull requests. Clean code, clear changes, obvious improvements to suggest. In production, it encountered messy legacy code, unclear requirements, and PRs that were architectural experiments rather than feature work.

The agent didn't know how to handle ambiguity. It treated every PR the same way—suggesting refactors on throwaway prototypes and nitpicking formatting on urgent hotfixes. It had no concept of context or priority.

Assumption 2: "Developers want fully automated code review."

Turns out they don't. They want assistance with code review, not replacement. They want help catching bugs they might miss, not prescriptive style enforcement. They want augmentation of their judgment, not substitution.

My agent tried to do everything, so developers trusted it to do nothing. A tool that attempts full automation creates more cognitive load than it removes—because now you have to review the AI's work instead of the code directly.

Assumption 3: "More intelligence means more value."

I used the most capable models available, thinking that more sophisticated AI would produce better results. But sophistication without constraints is just noise. The agent generated thoughtful, nuanced feedback that was often correct but always too verbose.

Developers stopped reading the feedback because parsing three paragraphs of AI-generated analysis took longer than just reviewing the code themselves.

What Actually Makes AI Agents Work

After the failure, I talked to teams successfully using AI agents in production. The pattern that emerged was clear: working agents are narrowly scoped, explicitly bounded, and deeply integrated into existing workflows.

Successful agents solve one problem well, not many problems poorly. Instead of "automate code review," think "flag potential security vulnerabilities in authentication code." Instead of "write documentation," think "generate API endpoint summaries from code."

Successful agents augment human decisions, not replace them. The best agents I've seen act as advisors that surface information humans would miss, not executors that make decisions autonomously. They highlight, suggest, and warn—but humans remain in control.

Successful agents fail gracefully and explicitly. When my agent encountered something it couldn't handle, it either tried anyway (creating noise) or failed silently (losing trust). Good agents say "I don't have enough context to help with this" instead of guessing.

Successful agents integrate into existing tools, not create new workflows. Developers didn't want to visit a separate dashboard to see agent feedback. They wanted feedback inline in GitHub, in their editor, in tools they already use daily.

The Architecture That Actually Works

When I rebuilt the agent with these lessons, the architecture changed completely.

Narrow scope: Security vulnerability detection only. Instead of general code review, the agent focused exclusively on identifying potential security issues—SQL injection risks, authentication bypass vulnerabilities, insecure data handling.

Human-in-the-loop: Flags issues, doesn't fix them. When the agent detected a potential vulnerability, it added a comment with: 1) the specific issue, 2) why it's concerning, 3) a reference to the OWASP guideline, 4) a question asking if this is intentional. Developers maintained full control.

Explicit uncertainty: Confidence scoring. Every flag included a confidence score. "High confidence: this SQL query is vulnerable to injection" versus "Low confidence: this authentication check might be bypassable." Developers learned which flags to prioritize.

Contextual awareness: Different rules for different code. The agent learned to recognize authentication code, payment processing, user input handling, and third-party integrations. It applied different security checks to different contexts instead of one-size-fits-all rules.

Integration: GitHub Actions + inline comments. The agent ran automatically on every PR as part of the existing CI pipeline. Feedback appeared inline on the exact lines of code in question. No separate dashboards, no new tools to learn.

The rebuilt agent got adopted immediately. Developers trusted it because it was narrow, accurate, and respectful of their judgment.

The Technical Challenges You'll Actually Face

Building agents that work in production requires solving problems that never appear in tutorials.

Context extraction is harder than reasoning. Your agent needs to understand not just the code, but the broader system architecture, the team's conventions, the project requirements, and the specific circumstances of this particular change. Extracting that context reliably is harder than any inference task.

Tools like the Data Extractor help pull structured information from unstructured sources—commit messages, PR descriptions, linked issues. The AI Literature Review Assistant can synthesize documentation and best practices relevant to the code being reviewed.

Confidence calibration matters more than accuracy. An agent that's right 95% of the time but can't tell you which 5% it's uncertain about is worse than an agent that's right 90% of the time and accurately flags its uncertainty. Spending time on confidence scoring is never wasted.

Feedback clarity beats feedback completeness. Long, thorough explanations get ignored. Short, actionable feedback gets adopted. Use tools like Make It Small to distill verbose AI outputs into essential insights. Then use Improve Text to ensure the condensed version is clear and specific.

Integration effort exceeds agent logic. You'll spend 20% of your time building the agent's intelligence and 80% integrating it into existing tools, handling edge cases, managing API rate limits, and making the user experience seamless. The Task Prioritizer becomes invaluable for managing this complexity.

Iteration based on user feedback is mandatory. Your first version will miss the mark. Your second version will be closer. Your tenth version might actually work. Building agents requires tight feedback loops with actual users, not just technical validation.

The Mistakes That Kill Agent Projects

Most agent projects fail for predictable reasons. Here's what kills them:

Scope creep destroys focus. "Let's also have it check code style, suggest refactors, and estimate task complexity!" No. Every additional capability reduces trust in the core capability. Start narrow, prove value, then expand carefully.

Over-automation breeds resentment. Users need control. Agents that act without asking permission, or require elaborate overrides to ignore, get disabled. Opt-in beats opt-out. Suggestions beat mandates.

Poor error handling destroys trust. When your agent crashes on edge cases or produces obviously wrong output, users lose confidence in everything it does. One bad suggestion makes them question all future suggestions. Fail explicitly and gracefully, or don't ship.

Ignoring the integration cost. If using your agent requires learning new tools, changing workflows, or adding steps to existing processes, adoption will be slow or nonexistent. The best agents disappear into existing workflows.

Solving problems users don't have. I built an agent to automate code review because I thought it would save time. What developers actually wanted was help catching security vulnerabilities they might miss. I built what I thought was valuable, not what users actually needed.

The Future of Agents That Actually Ship

The agents that will succeed in production aren't the ones that try to be fully autonomous. They're the ones that augment human work in narrow, well-defined ways.

Specialized over general. An agent that generates API documentation from code signatures will get more adoption than an agent that "writes all your documentation." Specialization enables trust because the scope is clear and the failure modes are bounded.

Transparent over opaque. Users need to understand what the agent is doing and why. Black box agents that produce outputs without explanation don't build confidence. Show your work. Make the reasoning visible.

Interruptible over autonomous. The ability to stop, redirect, or override the agent at any point is more valuable than fully autonomous operation. Human judgment remains the ultimate authority.

Integrated over standalone. Agents that live inside existing tools (IDE, GitHub, Slack, etc.) get used. Agents that require separate dashboards or new workflows get ignored.

What I'd Do Differently

If I were starting over, here's what I'd change:

Start by observing workflows for a week. Don't build what you think would be useful. Watch how people actually work, identify the most repetitive or error-prone parts, and build agents that target those specific friction points.

Build the integration first, intelligence second. Prove you can deliver feedback in the right place, at the right time, in the right format before investing heavily in agent sophistication. A simple heuristic delivered well beats sophisticated AI delivered poorly.

Use multiple models for different tasks. Don't assume one AI model is best for everything. Use platforms like [Crompt AI] to compare how different models handle your specific use cases. GPT-5 might be better at creative suggestions. Claude Opus 4.1 might be better at rigorous analysis. Gemini 2.5 Pro might be better at synthesizing documentation.

Ship a minimal version to three users first. Don't build for the whole team. Find three early adopters who'll give honest feedback, iterate rapidly based on their input, and only expand when they can't imagine working without it.

Measure adoption, not capability. The question isn't "can the agent do this?" It's "do people actually use it?" Usage metrics reveal whether you're solving a real problem or building impressive technology nobody wants.

The Real Lesson

Building AI agents that work in production isn't about having access to the best models or the most sophisticated architecture. It's about deeply understanding the human workflows you're trying to augment and building the narrowest possible tool that adds value without adding friction.

My failed code review agent taught me that autonomous AI is a solution looking for a problem. What developers actually need are smart assistants that make their existing work faster and more accurate—not replacements that try to do everything.

The agents that succeed are boring. They do one thing, they do it reliably, and they integrate so seamlessly into existing workflows that people forget they're using AI at all.

That's the goal. Not impressive demos. Not autonomous systems. Just useful tools that make real work easier.

-Leena:)

Top comments (0)