| name | cross-validate |
| description | Format a result, derivation, or numerical value for independent verification by a second model. Use when you want a cross-check on an important or contested result. |
/cross-validate
Format a physics or mathematics claim for cross-model validation.
Use this when Claude has produced a result you want to check against a second AI
model (Gemini, ChatGPT, or a fresh Claude context). Different models fail in
different ways on the same physics, so agreement between models is meaningful
evidence; disagreement tells you exactly where to look harder.
Inspired by the "hallucination orthogonality" principle and council-mode
verification in flonat/claude-research,
and the physics-specific failure modes documented by Tim Andersen
(How to use Claude to do physics).
Usage
/cross-validate "the Gaussian integral sqrt(pi) follows from squaring and polar coordinates"
/cross-validate (no argument — validate the last substantial result)
Steps
Step 1 — State the claim precisely.
Write the claim as a self-contained statement including:
- The exact formula or result
- All notation and conventions needed to read it (do not assume the other model
shares your conventions)
- The domain of validity or the specific input values
Example:
Claim: The Gaussian integral I = ∫_{-∞}^{∞} e^{-x²} dx equals √π.
Check this by computing I² = ∫∫ e^{-(x²+y²)} dx dy in polar coordinates,
and confirm the radial integral gives π.
Step 2 — List the specific checkpoints.
Identify what a second model should verify. Focus on the known Claude weak spots:
- Dimensional analysis: are all quantities dimensionally consistent?
- Sign conventions: which sign convention is being used and is it applied consistently?
- Formula provenance: is this formula standard? Does it appear (with the same
normalisation) in a named reference?
- Special-case check: does the result reduce correctly at a known special value?
- Step that looks too easy: any step summarised as "one computes" or "it follows
that" — ask the other model to expand it.
Step 3 — Output the validation prompt.
Produce a prompt ready to paste into another model. Format:
I want to verify a specific mathematical claim. Please check it independently —
do not try to agree with me, just derive it yourself from scratch.
[Exact statement from Step 1]
Please check:
1. [Checkpoint from Step 2]
2. [Checkpoint from Step 2]
...
If you reach a different answer, say so and explain where the derivations diverge.
Step 4 — After the user returns with the second model's answer.
Compare the two answers:
| Outcome | Interpretation |
|---|
| Both agree | High confidence — proceed |
| Disagree on a sign or factor | Check the normalisation convention; one model is using a different definition |
| Disagree on the method | Both might be right via different routes — or one is wrong; trace the discrepancy |
| Second model refuses or is vague | Try a fresh Claude session instead |
Report which specific step or factor differs and what the most likely source of
the discrepancy is.
Free scriptable option
The Gemini CLI can be called from
the terminal:
gemini -p "$(cat /tmp/validation_prompt.txt)"
This lets you run the second-model check from the same terminal without switching
context. The cross-validate skill can write the prompt to /tmp/validation_prompt.txt
automatically if you pass --write-prompt.
