DEV Community

Cover image for The Bug AI Can't Find Isn't in the Code
synthaicode
synthaicode

Posted on

The Bug AI Can't Find Isn't in the Code

AI checked the code. Checked the tests. Checked the code again. Everything looks fine—but the bug persists.

Sound familiar?

The problem isn't that AI is bad at analysis. The problem is outside AI's context entirely.

When "Check Harder" Doesn't Work

Without additional context, AI can enter a loop:

  1. Check the code → looks fine
  2. Check the tests → looks fine
  3. Check the code again → still fine
  4. Check the tests again → still fine
  5. Stuck

The problem exists. AI can't find it. Not because AI is bad at analysis—because the cause is outside its context.

What AI Can't See

AI has a field of vision. It sees what's in context: code, requirements, conversation history.

What it doesn't see: everything outside that context.

AI's visible context:

    ┌───────────────┐
    │ AI's Context  │  ← AI searches here
    │               │
    │  (code)       │
    │  (tests)      │
    │  (logs)       │
    └───────────────┘

    The blind spot remains dark.
Enter fullscreen mode Exit fullscreen mode
With human guidance:

    ┌───────────────┐
    │ AI's Context  │
    │               │
    │  (code)       │
    │  (tests)      │
    │  (logs)       │
    └───────────────┘
            │
            ▼  "Also consider X"
    ┌───────────────┐
    │ Illuminated   │  ← Now visible
    │ blind spot    │
    └───────────────┘
Enter fullscreen mode Exit fullscreen mode

You're not telling AI how to analyze. You're showing it where to look.

Case Study: The OHLC Bar Test Mystery

Real example from financial data processing.

Situation:

  • Building OHLC (Open-High-Low-Close) bar aggregation
  • 1-minute bars: tests pass ✓
  • 5-minute bars: tests fail intermittently ✗

AI's Response:

The AI checked:

  • Aggregation logic → correct
  • Time window calculations → correct
  • Data structures → correct
  • Edge cases → handled

Every review found nothing wrong. The code was logically sound.

But tests kept failing. Sometimes. Not always.

AI was stuck. It had examined everything in its context multiple times. No issues found.

The Human Intervention:

"Could the execution time affect the results?"

This single question injected new context.

The Discovery:

Test data was generated based on system clock time. The code used DateTime.Now to create test fixtures.

  • Run at 10:01 → 5-minute window aligns one way
  • Run at 10:03 → 5-minute window aligns differently

The test wasn't flaky. It was time-dependent. Same logic, different execution moments, different boundary conditions.

Why AI Missed It:

The system clock wasn't in the conversation. It wasn't in the code review scope. It wasn't mentioned in requirements.

It was outside AI's context entirely.

No amount of "check harder" would have found it. The AI needed someone to illuminate the blind spot.

Context-Outside Events

This pattern has a name: context-outside events.

In Context Outside Context
Source code System environment
Test code Execution timing
Error messages Infrastructure state
Documentation Runtime dependencies

When AI spins on a problem without progress, ask: What isn't AI seeing?

The answer is usually something environmental, temporal, or infrastructural—things that don't appear in code.

Your Job: Expand the Frame

This clarifies what humans uniquely contribute:

AI Strength Human Strength
Deep analysis within context Awareness beyond context
Pattern matching in visible data Intuition about invisible factors
Exhaustive checking "What if it's not in the code?"

You don't need to out-analyze AI. You need to expand the frame.

In Practice: Good vs. Bad Guidance

Good: Expanding Context

"Consider that this runs in a containerized environment 
with shared network resources."

"The database connection pool is limited to 10 connections."

"This service restarts nightly at 3 AM."
Enter fullscreen mode Exit fullscreen mode

These add context. They illuminate factors AI wouldn't know to consider.

Bad: Micromanaging Implementation

"Use a for loop, not a foreach."

"Put the null check on line 47."

"Name the variable 'tempCounter'."
Enter fullscreen mode Exit fullscreen mode

These control implementation. They remove AI judgment without adding visibility.

The Difference

Question Micromanagement Scope Expansion
What are you specifying? Implementation details Environmental context
What's the effect on AI? Constrains choices Expands awareness
When is it useful? Rarely When AI is stuck
What does it add? Your preferences Your visibility

Signs AI Needs Context, Not More Analysis

Watch for these patterns:

  • Same checks repeated with same results
  • "I don't see any issues in the code"
  • Intermittent failures with no pattern
  • Works locally, fails in CI
  • Passes alone, fails in suite

These all suggest: the cause is outside AI's current context.

Your job: figure out what's outside, and bring it in.

Top comments (0)