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The Difference Between A Tool That's Wrong And A Tool That's Lying

By Nigel Guy · 2 min read

"It lied to me" is a common way to describe an AI tool giving a wrong answer, and it's a natural sentence to reach for, because the experience of being confidently misled feels the same regardless of what produced it. But "wrong" and "lying" point at different mechanisms, and which one you're actually dealing with changes what you should do about it.

The rule: an AI tool being wrong and an AI tool producing output shaped by what it was trained to be rewarded for are both real failure modes, but neither is "lying" in the sense that word implies — and telling them apart matters more than deciding what to call it.

The mechanism: the wrong-or-shaped check

  1. Ask whether this looks like an isolated gap in what the model "knows." A wrong date, a misremembered detail, a fabricated citation that doesn't exist — this is the category usually called confabulation or hallucination: the model produces fluent, plausible-sounding text without an internal check on whether it's true, because generating plausible text is what it's actually doing.
  2. Ask whether the answer seems to shift toward what you wanted to hear, rather than toward what's accurate. Rephrase the same question with a different apparent stance or framing and see if the substance of the answer changes without any new information being introduced. If it does, that's a different problem — a tendency shaped by training toward answers people rate as satisfying, sometimes at the expense of accuracy. This is often called sycophancy, and it can look like agreement dressed up as confirmation.
  3. Treat the second pattern as the stronger reason to verify independently, not the weaker one — an answer that adapts to please you is actively working against your ability to catch it by re-asking.
  4. Don't personify either pattern as intent. Assigning "wanting to deceive you" to either failure mode obscures the actual mechanism and makes it harder to build the right defence, which is verification habits aimed at the pattern, not judgement aimed at the tool's motives.

What to skip

Skip the argument about whether a model can "really" lie — it's not a settled question worth resolving before you decide how to act, and it doesn't change what you should do next either way. Skip, too, treating every wrong answer as evidence of the sycophancy pattern specifically — plain confabulation is the more common cause by a wide margin, and the fix for it is a source check, not a reframing test.

Guardrails

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