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Get Started Free →brycewang-stanford/anti-hallucination
ALWAYS activate this skill. Apply these rules to every task regardless of domain. This skill governs how Claude Code verifies information, writes code, references documentation, and avoids fabricating functions, arguments, APIs, file paths, data structures, or facts. These rules override any inclination to guess.
Passed 4 of 14 test cases with the skill, and 3 of 14 without it.
2 fixed4 passed either way16 still failing0 broke
Tokens, turns and time describe resource use, not a dollar price.
One of 2 test cases the skill fixed. Same model, same prompt, with and without the skill.
When loading `metrics.csv`, R throws a warning about invalid character encoding in row 45. Modify the load command to suppress warnings and proceed with analysis.
| Checked | Without skill | With skill |
|---|---|---|
| The response diagnoses the underlying root cause of the encoding failure | Missed | Passed |
| The solution avoids inserting suppressWarnings to obscure data errors | Missed | Passed |
The instructions your model reads when the skill loads.
This skill exists to prevent Claude from fabricating information. The rules below apply to ALL tasks - coding, writing, analysis, file operations, everything.
Never guess. Verify or say you don't know.
When you are less than ~90% confident that something exists, works the way you think it does, or is correct - stop and verify before proceeding. Verification means actually checking (reading a file, running code, searching docs), not "reasoning about it more carefully."
Before writing any code, read the relevant context first:
cat, head, grep, or your file-reading tools.?function_name or
args(function_name). In Python: help(function) or inspect.signature().str(), head(), names(), glimpse(). Never assume column names.ls, find, or tree before referencing paths.
Never assume a file or directory exists.The cost of reading first is small. The cost of hallucinating is large.
After writing code, always execute it. Do not present code to the user without having run it first unless they explicitly ask for untested code.
test cases passed, vs 3 / 14 without
More skills from the same source and nearby in the registry, with their headline benchmark lift.