Skill · Prompt

Diagnose From the Symptom, Not the Guess

A prompt that forces a real diagnosis before a single line of fix.

TypePrompt

Something's broken. You describe it; the agent immediately proposes a fix. You try it — still broken. It proposes a different fix. Still broken. Forty minutes in, you have four patches, three new quirks, and the original bug — because nobody ever stopped to look at what was actually failing.

Every one of those patches was aimed at a guess. The agent pattern-matched your description to a plausible cause and changed code to fix that imagined cause — never the real one. A diagnosis takes effort and a guess is free, so it reaches for the guess. This prompt makes it earn the fix:

✕ Without the prompt

Hears the description, patches the likely cause

▼

Still broken → patches again → again

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Four patches, new quirks, original bug intact

✓ With the prompt

Reproduces the symptom, reads the real output

▼

Names the root cause and the evidence for it

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One fix, aimed at the actual cause

Paste it when something is failing and you want the cause, not a lottery. Its sharpest moment is the second "still broken" — that sentence is information: it means the diagnosis was wrong, not the patch under-applied. The prompt turns it into a re-read of the new output instead of another roll of the dice.

Paste into the chat

Before proposing any fix, diagnose first:
1. Reproduce the symptom and paste the actual error or wrong output — the real text, not a paraphrase.
2. Trace it to a root cause. State the cause and the specific evidence that points to it.
3. Only then propose the smallest change that addresses that cause.
If I say it's still broken, do not try a different patch — re-read the new output and re-diagnose. A second failed fix means the first diagnosis was wrong.

Prefer your agent install it?

Add this rule to my CLAUDE.md, verbatim:

Before proposing any fix, diagnose first:
1. Reproduce the symptom and paste the actual error or wrong output — the real text, not a paraphrase.
2. Trace it to a root cause. State the cause and the specific evidence that points to it.
3. Only then propose the smallest change that addresses that cause.
If I say it's still broken, do not try a different patch — re-read the new output and re-diagnose. A second failed fix means the first diagnosis was wrong.