diff --git a/conductor/tech-stack.md b/conductor/tech-stack.md
index 4e79325c..d631d31a 100644
--- a/conductor/tech-stack.md
+++ b/conductor/tech-stack.md
@@ -1,8 +1,10 @@
 # Technology Stack: Manual Slop
 
+> **Core Value (added 2026-06-25):** C11/Odin/Jai semantics in this Python runtime. See `conductor/product-guidelines.md` "Core Value", `conductor/code_styleguides/data_oriented_design.md` §8.5, and `conductor/code_styleguides/python.md` §17. Banned: `dict[str, Any]`, `Any`, `Optional[T]`, `hasattr()` for entity dispatch, `.get()` on known fields. Use typed `@dataclass(frozen=True, slots=True)` with explicit fields. Use `Result[T]` + `NIL_T` sentinels.
+
 ## Core Language
 
-- **Python 3.11+**
+- **Python 3.11+** (used for practical reasons; the convention is to make it behave like a statically-typed value-typed language; see Core Value above)
 
 ## GUI Frameworks