math-identity-check — numerically audit elementary identities

Two expressions in, one verdict out. Heavy lifting lives in skills/_shared/eml_core/identity.py; this skill is the user-facing entry point.

When this skill triggers

Triggers on: "is identity X true?", "does LHS equal RHS?", "verify sin(x)^2 + cos(x)^2 = 1", "check this trig identity", "is the LLM right that sqrt(x^2+y^2) = x+y?", "audit this step of a derivation".

Does not trigger on: requests for symbolic proof, simplification, or factoring (use sympy/CAS); requests to fit a formula from data (that's /eml-fit); requests to verify an EML tree specifically (that's /eml-check).

How to run

All commands below assume cwd is the repo root. From an installed plugin's root, drop the leading eml-skill/; from this skill's own directory, drop eml-skill/skills/math-identity-check/.

python eml-skill/skills/math-identity-check/scripts/check.py \
    --lhs "sin(x)**2 + cos(x)**2" \
    --rhs "1" \
    --out-dir ./