Rate Decomposition (Nominal = Real + Breakeven)

Every nominal Treasury yield is a real yield plus inflation compensation. This operator makes that identity operational: levels per tenor, a rolling attribution whose two legs sum exactly to the nominal change, and a named driver leg — so "yields rose" always comes with "because the real leg / the inflation leg moved".

Reading it

• Real-driven rise — growth/term-premium repricing; the inflation anchor is intact.
• Inflation-driven rise — compensation is moving; check the breakeven monitor legs (5Y/10Y pair separates a spot scare from de-anchoring).
• The self-check row reports the computed breakevens against FRED's own published series — the identity audited against the source.

Conventions, honestly

The 2Y leg rides the Fed Board's GSW fitted zero-coupon curve (weekly file). It is a slightly different convention from the par cash series — declared in meta.tenor_sources, never mixed within a tenor. Breakevens are cash-market compensation, not inflation swaps and not expectations.