diff --git a/docs/design/INDEX.md b/docs/design/INDEX.md
index fe13ef7..e7411f5 100644
--- a/docs/design/INDEX.md
+++ b/docs/design/INDEX.md
@@ -742,6 +742,32 @@ notation — superseding the cycle-0017 flat-ascii model and its renderer-defect
 workaround. The DOT/SVG are Graphviz-version-dependent and not golden-tested; the
 deterministic JSON model is the asserted contract.
 
+**Realization (cycle 0034 — structural-constant bind: a knob *removed* from
+param_space, #55).** `PrimitiveBuilder::bind(slot, value)` adds the **third** param
+category beside the topology factory-arg (C7/C19) and the tuning param (the
+cycle-0016 value-pin): a **structural constant**. The cycle-0016 binding *pins* a
+value in the injected vector while the knob **stays** in `param_space` (a tuning
+param the sweep varies); `bind` instead **removes** the slot from `param_space`
+entirely — the knob is gone, not fixed. The discriminator is the #55
+deform-vs-tune test: a value whose variation yields another valid point of the
+*same* strategy is a **tuning param** (stays in `param_space`); a value whose
+variation *deforms* the strategy into a different one (e.g. the `2` of an
+"SMA2-entry" bound to its two-candle construction) is a **structural constant**
+(bound out), so a sweep never enumerates deformed strategies as valid family
+members. Mechanically `bind` shrinks the builder's declared param surface
+(`schema.params`) and wraps its build closure to re-splice the constant at its
+original positional slot; the construction layer
+(`collect_params`/`lower_items`/`param_space`/`compile_with_params`) is
+**byte-unchanged** — both dock sites already key off `builder.params()`, so the
+shrink propagates for free, and chained binds reconstruct the correct positional
+vector because each layer computes its slot index relative to the param list it
+sees. C23 is unaffected: `bind` resolves the param **name** to a position at
+**authoring** time (the by-name authoring address space, the 0032 amendment) and
+the compilat stays wired by raw index — the name never reaches it. The
+complementary question — exporting a **named frozen** strategy (all/most knobs
+bound) as a reusable blueprint *value* — is deferred (#60); `bind` ships only the
+per-knob overlay, no registry (C9/C10 intact).
+
 ### C20 — Strategy ↔ harness; the harness is the root sim graph
 **Guarantee.** A **strategy** is a reusable composite-node blueprint (C9):
 broker-, data-, and viz-independent, with inputs declared as named **roles**