diff --git a/bin/axiomcode b/bin/axiomcode
index 3e1d32c87..01c25295b 100755
--- a/bin/axiomcode
+++ b/bin/axiomcode
@@ -25,6 +25,8 @@
 #
 # Engine options:
 #   --dispatch-cap <N|off>   --lib-depth <N>   --jdk-depth <N>   --taint <on|off>
+#   --closed-world <on|off>  narrow the dispatch fan to constructed types (TypeScript), recording
+#                            each dropped edge as an assumption row
 #
 # Commands:
 #   parser <src-dir> <ir-dir> [--version V] [--exclude-tests]
@@ -195,7 +197,7 @@ case "$cmd" in
       --language) lang="$2"; shift 2;; --src) src="$2"; shift 2;; --out) out="$2"; shift 2;;
       --library) libs="$2"; shift 2;; --progress) progress="$2"; shift 2;;
       --version|--slug) version="$2"; shift 2;; --exclude-tests) popts+=(--exclude-tests); shift;;
-      --intermediate|--dispatch-cap|--lib-depth|--jdk-depth|--taint) rest+=("$1" "$2"); shift 2;;
+      --intermediate|--dispatch-cap|--lib-depth|--jdk-depth|--taint|--closed-world) rest+=("$1" "$2"); shift 2;;
       --debug) rest+=(--debug); shift;;
       --*) die "unknown option $1 (try --help)";;
       *) pos+=("$1"); shift;; esac; done
diff --git a/graph/bundle/SCHEMA.md b/graph/bundle/SCHEMA.md
index 625aac8d3..ff013e58b 100644
--- a/graph/bundle/SCHEMA.md
+++ b/graph/bundle/SCHEMA.md
@@ -215,6 +215,7 @@ What produced this bundle: one key/value row per fact about the run (language, e
 | `client_ir` | all | Path of the client IR directory the engine read. |
 | `library_roots` | all | Comma-separated library IR roots staged as the type oracle; empty for a client-only run. |
 | `dispatch_cap` | all | Fan-width cap on virtual dispatch in effect; `off` when uncapped. |
+| `dispatch_closed_world` | all | `on` when the dispatch fan was narrowed to types the analysed code constructs (a closed-world premise; each dropped edge is an assumption row); `off` otherwise. Read by TypeScript. |
 | `jdk_depth` | all | Platform-library hop cap (engine-ii). |
 | `lib_depth` | all | External-library hop cap; `uncapped` when unset. |
 | `engine_ii` | all | `on` when the library-frontier forward chain (engine-ii) was included; `off` for a client-only solve. |
diff --git a/graph/bundle/schema.ts b/graph/bundle/schema.ts
index 87b31156a..23e6b0adb 100644
--- a/graph/bundle/schema.ts
+++ b/graph/bundle/schema.ts
@@ -384,6 +384,7 @@ export const VOCAB: readonly VocabSpec[] = [
   { table: 'run', column: 'key', value: 'client_ir', languages: 'all', meaning: 'Path of the client IR directory the engine read.' },
   { table: 'run', column: 'key', value: 'library_roots', languages: 'all', meaning: 'Comma-separated library IR roots staged as the type oracle; empty for a client-only run.' },
   { table: 'run', column: 'key', value: 'dispatch_cap', languages: 'all', meaning: 'Fan-width cap on virtual dispatch in effect; `off` when uncapped.' },
+  { table: 'run', column: 'key', value: 'dispatch_closed_world', languages: 'all', meaning: '`on` when the dispatch fan was narrowed to types the analysed code constructs (a closed-world premise; each dropped edge is an assumption row); `off` otherwise. Read by TypeScript.' },
   { table: 'run', column: 'key', value: 'jdk_depth', languages: 'all', meaning: 'Platform-library hop cap (engine-ii).' },
   { table: 'run', column: 'key', value: 'lib_depth', languages: 'all', meaning: 'External-library hop cap; `uncapped` when unset.' },
   { table: 'run', column: 'key', value: 'engine_ii', languages: 'all', meaning: '`on` when the library-frontier forward chain (engine-ii) was included; `off` for a client-only solve.' },
diff --git a/graph/csharp/souffle/decls_all.dl b/graph/csharp/souffle/decls_all.dl
index 4372d0de6..25be747de 100644
--- a/graph/csharp/souffle/decls_all.dl
+++ b/graph/csharp/souffle/decls_all.dl
@@ -18,6 +18,7 @@
 // ============================================================================
 
 .decl dispatch_cap(c0:symbol)
+.decl dispatch_closed_world(c0:symbol)
 .decl jdk_max_depth(c0:number)
 .decl lib_max_depth(c0:number)
 .decl runtime_observed_edge(c0:symbol,c1:symbol,c2:symbol)
diff --git a/graph/csharp/souffle/gen_decls_all.py b/graph/csharp/souffle/gen_decls_all.py
index 4ccb74525..7a8f6cc07 100644
--- a/graph/csharp/souffle/gen_decls_all.py
+++ b/graph/csharp/souffle/gen_decls_all.py
@@ -69,6 +69,9 @@
     # --dispatch-cap K: refuse a virtual-dispatch fan wider than K. Recall-risky, so
     # opt-in; empty means uncapped, which is the answer that cannot be wrong.
     "dispatch_cap": ("symbol",),
+    # --closed-world on: narrow the dispatch fan to constructed types (#473). Staged
+    # for every language by the shared executor; no C# rule reads it yet.
+    "dispatch_closed_world": ("symbol",),
     # --lib-depth: how far a client->lib chain is expanded. Empty means uncapped.
     "lib_max_depth": ("number",),
     # The shared executor ALWAYS stages these two, for every language, and emits one
diff --git a/graph/java/souffle/decls_all.dl b/graph/java/souffle/decls_all.dl
index 625f6581d..0298ce49a 100644
--- a/graph/java/souffle/decls_all.dl
+++ b/graph/java/souffle/decls_all.dl
@@ -463,6 +463,7 @@
 .decl lib_dispatch_width_low(c0:symbol,c1:number)
 .decl lib_wide_dispatch(c0:symbol)
 .decl dispatch_cap(c0:symbol)
+.decl dispatch_closed_world(c0:symbol)
 .decl field_final(c0:symbol)
 .decl field_init_new_type(c0:symbol,c1:symbol)
 .decl field_multi_new(c0:symbol)
diff --git a/graph/javascript/souffle/decls_all.dl b/graph/javascript/souffle/decls_all.dl
index a126c63c0..cae221d9e 100644
--- a/graph/javascript/souffle/decls_all.dl
+++ b/graph/javascript/souffle/decls_all.dl
@@ -380,6 +380,7 @@
 .decl literal_contains_method_nested(c0:symbol, c1:symbol)
 // ── executor knobs (written by run-souffle.sh for every language; unread here) ──
 .decl dispatch_cap(c0:symbol)
+.decl dispatch_closed_world(c0:symbol)
 .decl jdk_max_depth(c0:number)
 .decl lib_max_depth(c0:number)
 .decl taint_gating(c0:symbol)
diff --git a/graph/pipeline/run-souffle.sh b/graph/pipeline/run-souffle.sh
index 4d47f08cc..0ec319717 100755
--- a/graph/pipeline/run-souffle.sh
+++ b/graph/pipeline/run-souffle.sh
@@ -45,7 +45,10 @@ DISPATCH_CAP="${DISPATCH_CAP:-20}"   # fan-width cap on virtual dispatch. DEFAUL
 LANG_ARG=""   # which rule set under graph/<lang>/ to run. Default java.
 TAINT=""      # --taint on → gate lib→lib GROW on client-seeded data flow (dataflow/taint.dl). Also
               # settable via env AXIOM_TAINT_GATING=on. Empty = ungated (default behavior).
-MODE="run"    # run | print-engine-id | emit-program — the last two need no IR and no souffle
+CLOSED_WORLD="" # --closed-world on → narrow the dispatch fan to types the program constructs (RTA),
+              # and record every edge that drops as an assumption row. Env AXIOM_DISPATCH_CLOSED_WORLD=on.
+              # Empty = the fan is every declared override (default). See #473.
+MODE="run"   # run | print-engine-id | emit-program — the last two need no IR and no souffle
 EMIT=""
 while [ $# -gt 0 ]; do case "$1" in
   --client-ir) CLIENT="$2"; shift 2;; --library) LIB="$2"; shift 2;;
@@ -54,6 +57,7 @@ while [ $# -gt 0 ]; do case "$1" in
   --dispatch-cap) DISPATCH_CAP="$2"; shift 2;;
   --lib-depth) LIB_DEPTH="$2"; shift 2;;
   --taint) TAINT="$2"; shift 2;;
+  --closed-world) CLOSED_WORLD="$2"; shift 2;;
   --language) LANG_ARG="$2"; shift 2;;
   --print-engine-id) MODE="print-engine-id"; shift;;
   --emit-program) MODE="emit-program"; EMIT="$2"; shift 2;;
@@ -195,7 +199,7 @@ write_program(){
   map_rels_su "$TPL/client-ir.map" || return 1
   map_rels_su "$TPL/lib.map" sig || return 1
   for r in $LIB_BODY; do _SU+=("$r"); done
-  _SU+=(jdk_max_depth lib_max_depth taint_gating dispatch_cap)
+  _SU+=(jdk_max_depth lib_max_depth taint_gating dispatch_cap dispatch_closed_world)
   sort_unique_su
   PROGRAM_INPUTS=(${_SU[@]+"${_SU[@]}"})
   # rfc4180=true: the IR is CSV, not TSV. The parser quotes any field containing a
@@ -247,7 +251,7 @@ write_program(){
 # the expected one, each exactly once, with nothing extra. Exit status only: no pipe to lose.
 verify_program(){
   awk -v cmap="$TPL/client-ir.map" -v lmap="$TPL/lib.map" -v man="$DL/export_manifest.tsv" \
-      -v libsig=" $LIB_SIG " -v extra="$LIB_BODY jdk_max_depth lib_max_depth taint_gating dispatch_cap" '
+      -v libsig=" $LIB_SIG " -v extra="$LIB_BODY jdk_max_depth lib_max_depth taint_gating dispatch_cap dispatch_closed_world" '
     function want(line) { if (!(line in need)) { need[line] = 1; n++ } }
     function inp(r) { want(".input " r "(IO=file, filename=\"" r ".facts\", delimiter=\"\\t\", rfc4180=true)") }
     function maprels(path, sigonly,   l, rc, r, k) {
@@ -504,6 +508,17 @@ echo "▶ taint gating = $( [ -s "$FACTS/taint_gating.facts" ] && echo 'on (opt-
 CAP_EFF="${AXIOM_DISPATCH_CAP:-$DISPATCH_CAP}"
 case "$CAP_EFF" in off|none|no|0|"") CAP_EFF="";; esac
 [ -n "$CAP_EFF" ] && printf '%s\n' "$CAP_EFF" > "$FACTS/dispatch_cap.facts"
+
+# dispatch_closed_world — OPT-IN RTA narrowing of the dispatch fan (#473). The file always exists
+# so its .input directive is generated; EMPTY = the fan is every declared override (the default,
+# and what every golden pins). "on" admits only overrides a constructed or escaping type can
+# reach, and exports each dropped edge as an assumption row: the narrowing is sound only when
+# every construction is in the analysed code, so the bundle says it was made. Only front ends
+# that read the relation change; the others ignore it.
+: > "$FACTS/dispatch_closed_world.facts"
+CW_EFF="${AXIOM_DISPATCH_CLOSED_WORLD:-$CLOSED_WORLD}"
+case "$CW_EFF" in on|yes|1|true) CW_EFF="on"; printf 'on\n' > "$FACTS/dispatch_closed_world.facts";; *) CW_EFF="off";; esac
+echo "▶ dispatch closed world = $CW_EFF"
 echo "▶ dispatch cap = $( [ -s "$FACTS/dispatch_cap.facts" ] && echo "$(cat "$FACTS/dispatch_cap.facts") (default; --dispatch-cap off for unbounded reachability)" || echo 'OFF — uncapped/sound (sink & taint traversal)' )"
 
 # engine-ii (lib-frontier forward-chain) is GATED — default OFF so the build is CLIENT-ONLY
@@ -803,7 +818,7 @@ BUNDLE_FLAGS=(); [ "$DEBUG_BUNDLE" = "1" ] && BUNDLE_FLAGS+=(--debug)
 "${BUNDLE[@]}" --language "$LANG_ARG" --src "$SRC" --client-ir "$CLIENT" --raw "$RAW" --out "$OUT" \
   --library "$LIB" --lib-facts "$LIBDIR" "${BUNDLE_FLAGS[@]}" \
   --meta "engine_commit=$ENGINE_COMMIT" \
-  --meta "dispatch_cap=${CAP_EFF:-off}" --meta "jdk_depth=$JDK_DEPTH" --meta "lib_depth=${LIB_DEPTH:-uncapped}" \
+  --meta "dispatch_cap=${CAP_EFF:-off}" --meta "dispatch_closed_world=$CW_EFF" --meta "jdk_depth=$JDK_DEPTH" --meta "lib_depth=${LIB_DEPTH:-uncapped}" \
   --meta "engine_ii=$ENGINE_II_MODE" --meta "solve_iterations=$iter" --meta "solve_seconds=$((SOLVE_EPOCH-START_EPOCH))" \
   ${EXTRA_META[@]+"${EXTRA_META[@]}"}
 
diff --git a/graph/python/souffle/decls_all.dl b/graph/python/souffle/decls_all.dl
index 64b71d8fe..09a7d62c2 100644
--- a/graph/python/souffle/decls_all.dl
+++ b/graph/python/souffle/decls_all.dl
@@ -1,4 +1,5 @@
 .decl dispatch_cap(c0:symbol)
+.decl dispatch_closed_world(c0:symbol)
 .decl jdk_max_depth(c0:number)
 .decl lib_max_depth(c0:number)
 .decl taint_gating(c0:symbol)
diff --git a/graph/test/typescript/cases/83-closed-world-dispatch/src/handlers.ts b/graph/test/typescript/cases/83-closed-world-dispatch/src/handlers.ts
new file mode 100644
index 000000000..864290cb5
--- /dev/null
+++ b/graph/test/typescript/cases/83-closed-world-dispatch/src/handlers.ts
@@ -0,0 +1,55 @@
+// A call through an interface-typed receiver fans to every declared implementor by
+// default. `--closed-world on` narrows that fan to what the program can build (#473).
+// Each class below is one shape of "can the program build it":
+
+export interface Handler {
+  handle(x: string): string;
+}
+
+// constructed with `new`: stays in the narrowed fan
+export class Built implements Handler {
+  handle(x: string): string { return "b" + x; }
+}
+
+// never written in a `new`, but handed to a registry as a class VALUE that constructs it:
+// stays, because a class that escapes as a value can be built where the parser cannot see
+export class Registered implements Handler {
+  handle(x: string): string { return "r" + x; }
+}
+
+// named only as a TYPE: nothing can build it, so the narrowed fan drops it
+export class Unused implements Handler {
+  handle(x: string): string { return "u" + x; }
+}
+
+// never constructed itself, but a constructed subclass inherits its body: stays
+export abstract class Base implements Handler {
+  handle(x: string): string { return "base" + x; }
+}
+export class Leaf extends Base {}
+
+// a subclass nobody constructs, overriding: dropped
+export class Orphan extends Base {
+  handle(x: string): string { return "o" + x; }
+}
+
+type HandlerClass = new () => Handler;
+const registry: HandlerClass[] = [];
+export function register(c: HandlerClass): void { registry.push(c); }
+register(Registered);
+
+export function dispatch(h: Handler, x: string): string {
+  return h.handle(x);
+}
+
+export function main(): void {
+  const built = new Built();
+  const leaf = new Leaf();
+  let later: Unused | undefined;
+  let other: Orphan | undefined;
+  dispatch(built, "1");
+  dispatch(leaf, "2");
+  for (const C of registry) dispatch(new C(), "3");
+  void later;
+  void other;
+}
diff --git a/graph/test/typescript/cases/83-closed-world-dispatch/src/impl.ts b/graph/test/typescript/cases/83-closed-world-dispatch/src/impl.ts
new file mode 100644
index 000000000..eaedd82a7
--- /dev/null
+++ b/graph/test/typescript/cases/83-closed-world-dispatch/src/impl.ts
@@ -0,0 +1,12 @@
+import { Handler } from "./handlers";
+
+// declared in one module, handed to a container as a class VALUE from another
+// (`useClass: Provided` in module.ts): stays in the narrowed fan
+export class Provided implements Handler {
+  handle(x: string): string { return "p" + x; }
+}
+
+// imported by module.ts too, but only ever named there as a TYPE: dropped
+export class TypeOnly implements Handler {
+  handle(x: string): string { return "t" + x; }
+}
diff --git a/graph/test/typescript/cases/83-closed-world-dispatch/src/module.ts b/graph/test/typescript/cases/83-closed-world-dispatch/src/module.ts
new file mode 100644
index 000000000..fda3351a2
--- /dev/null
+++ b/graph/test/typescript/cases/83-closed-world-dispatch/src/module.ts
@@ -0,0 +1,7 @@
+import { Provided, TypeOnly } from "./impl";
+
+// The container shape: the class crosses a module boundary as an imported value and is
+// constructed by code the analysis does not see.
+export const providers = [{ provide: "handler", useClass: Provided }];
+
+export let pending: TypeOnly | undefined;
diff --git a/graph/test/typescript/expected/83-closed-world-dispatch.edges b/graph/test/typescript/expected/83-closed-world-dispatch.edges
new file mode 100644
index 000000000..3e35361f4
--- /dev/null
+++ b/graph/test/typescript/expected/83-closed-world-dispatch.edges
@@ -0,0 +1,16 @@
+ambiguous_unknown	CONSTRUCTOR_CALL	handlers#main() @L52 -> -
+ambiguous_unknown	METHOD_CALL	handlers#register(HandlerClass) @L38 -> -
+known_edge	CONSTRUCTOR_CALL	handlers#main() @L46 -> Built#<new>()
+known_edge	CONSTRUCTOR_CALL	handlers#main() @L47 -> Base#<new>()
+known_edge	FUNCTION_CALL	handlers#<module-init>() @L39 -> handlers#register(HandlerClass)
+known_edge	FUNCTION_CALL	handlers#main() @L50 -> handlers#dispatch(Handler,string)
+known_edge	FUNCTION_CALL	handlers#main() @L51 -> handlers#dispatch(Handler,string)
+known_edge	FUNCTION_CALL	handlers#main() @L52 -> handlers#dispatch(Handler,string)
+multi_inferred	METHOD_CALL	handlers#dispatch(Handler,string) @L42 -> Base#handle(string)
+multi_inferred	METHOD_CALL	handlers#dispatch(Handler,string) @L42 -> Built#handle(string)
+multi_inferred	METHOD_CALL	handlers#dispatch(Handler,string) @L42 -> Handler#handle(string)
+multi_inferred	METHOD_CALL	handlers#dispatch(Handler,string) @L42 -> Orphan#handle(string)
+multi_inferred	METHOD_CALL	handlers#dispatch(Handler,string) @L42 -> Provided#handle(string)
+multi_inferred	METHOD_CALL	handlers#dispatch(Handler,string) @L42 -> Registered#handle(string)
+multi_inferred	METHOD_CALL	handlers#dispatch(Handler,string) @L42 -> TypeOnly#handle(string)
+multi_inferred	METHOD_CALL	handlers#dispatch(Handler,string) @L42 -> Unused#handle(string)
diff --git a/graph/test/typescript/expected/83-closed-world-dispatch.entries b/graph/test/typescript/expected/83-closed-world-dispatch.entries
new file mode 100644
index 000000000..37921bcc4
--- /dev/null
+++ b/graph/test/typescript/expected/83-closed-world-dispatch.entries
@@ -0,0 +1,2 @@
+── entry_point (1) ──
+  unimported_module module#<module>   module.ts:1
diff --git a/graph/test/typescript/expected/83-closed-world-dispatch.envelope b/graph/test/typescript/expected/83-closed-world-dispatch.envelope
new file mode 100644
index 000000000..d8c90f4ff
--- /dev/null
+++ b/graph/test/typescript/expected/83-closed-world-dispatch.envelope
@@ -0,0 +1,8 @@
+nominal	handlers#Base.handle -> handlers#Orphan.handle
+nominal	handlers#Handler.handle -> handlers#Base.handle
+nominal	handlers#Handler.handle -> handlers#Built.handle
+nominal	handlers#Handler.handle -> handlers#Orphan.handle
+nominal	handlers#Handler.handle -> handlers#Registered.handle
+nominal	handlers#Handler.handle -> handlers#Unused.handle
+nominal	handlers#Handler.handle -> impl#Provided.handle
+nominal	handlers#Handler.handle -> impl#TypeOnly.handle
diff --git a/graph/test/typescript/expected/83-closed-world-dispatch.fields b/graph/test/typescript/expected/83-closed-world-dispatch.fields
new file mode 100644
index 000000000..e69de29bb
diff --git a/graph/test/typescript/expected/83-closed-world-dispatch.fields-oracle b/graph/test/typescript/expected/83-closed-world-dispatch.fields-oracle
new file mode 100644
index 000000000..3355e7406
--- /dev/null
+++ b/graph/test/typescript/expected/83-closed-world-dispatch.fields-oracle
@@ -0,0 +1,7 @@
+83-closed-world-dispatch [fields]
+  precision 0.0000   (0 correct, 0 wrong)
+  recall    0.0000   (0 of 0 the compiler resolved)
+  sites 0   resolved 0 
+  tiers 
+  access 
+  not scored: 0 rows whose target is not a client declaration
diff --git a/graph/test/typescript/expected/83-closed-world-dispatch.known-missing b/graph/test/typescript/expected/83-closed-world-dispatch.known-missing
new file mode 100644
index 000000000..15bb2695f
--- /dev/null
+++ b/graph/test/typescript/expected/83-closed-world-dispatch.known-missing
@@ -0,0 +1,7 @@
+# Accepted gaps for 83-closed-world-dispatch — each line is an edge the TypeScript compiler
+# resolves and this engine does not. A NEW missing edge fails the suite;
+# a line here that STARTS working also fails, so the debt cannot rot.
+# `new C()` where C is typed by a construct-signature alias: the compiler names the
+# alias's signature, the engine leaves the site ambiguous_unknown. Unrelated to the
+# closed-world fan this case is about.
+handlers#main() -> handlers#<arrow@36>()
diff --git a/graph/test/typescript/expected/83-closed-world-dispatch.oracle b/graph/test/typescript/expected/83-closed-world-dispatch.oracle
new file mode 100644
index 000000000..7f00d858a
--- /dev/null
+++ b/graph/test/typescript/expected/83-closed-world-dispatch.oracle
@@ -0,0 +1,9 @@
+oracle=6 engine=12 agree=5 missing=1 (known 1, NEW 0) extra=7
+  known    handlers#main() -> handlers#<arrow@36>()
+  extra    handlers#dispatch(Handler,string) -> Base#handle(string)
+  extra    handlers#dispatch(Handler,string) -> Built#handle(string)
+  extra    handlers#dispatch(Handler,string) -> Orphan#handle(string)
+  extra    handlers#dispatch(Handler,string) -> Provided#handle(string)
+  extra    handlers#dispatch(Handler,string) -> Registered#handle(string)
+  extra    handlers#dispatch(Handler,string) -> TypeOnly#handle(string)
+  extra    handlers#dispatch(Handler,string) -> Unused#handle(string)
diff --git a/graph/test/typescript/expected/83-closed-world-dispatch.type-use b/graph/test/typescript/expected/83-closed-world-dispatch.type-use
new file mode 100644
index 000000000..b398f762a
--- /dev/null
+++ b/graph/test/typescript/expected/83-closed-world-dispatch.type-use
@@ -0,0 +1,18 @@
+ambiguous_unknown	OBJECT_CREATION_TYPE	0	handlers [EXPRESSION] -> -
+known_edge	IMPLEMENTS_INTERFACE	0	Base [HERITAGE] -> Handler
+known_edge	IMPLEMENTS_INTERFACE	0	Built [HERITAGE] -> Handler
+known_edge	IMPLEMENTS_INTERFACE	0	Provided [HERITAGE] -> Handler
+known_edge	IMPLEMENTS_INTERFACE	0	Registered [HERITAGE] -> Handler
+known_edge	IMPLEMENTS_INTERFACE	0	TypeOnly [HERITAGE] -> Handler
+known_edge	IMPLEMENTS_INTERFACE	0	Unused [HERITAGE] -> Handler
+known_edge	METHOD_PARAM	0	handlers [METHOD_PARAM] -> Handler
+known_edge	METHOD_PARAM	0	handlers [METHOD_PARAM] -> HandlerClass
+known_edge	METHOD_RETURN	1	HandlerClass [TYPE] -> Handler
+known_edge	OBJECT_CREATION_TYPE	0	handlers [EXPRESSION] -> Built
+known_edge	OBJECT_CREATION_TYPE	0	handlers [EXPRESSION] -> Leaf
+known_edge	SUPER_TYPE	0	Leaf [HERITAGE] -> Base
+known_edge	SUPER_TYPE	0	Orphan [HERITAGE] -> Base
+known_edge	TYPE_ELEMENT	1	handlers [VARIABLE] -> HandlerClass
+known_edge	TYPE_ELEMENT	1	handlers [VARIABLE] -> Orphan
+known_edge	TYPE_ELEMENT	1	handlers [VARIABLE] -> Unused
+known_edge	TYPE_ELEMENT	1	module [VARIABLE] -> TypeOnly
diff --git a/graph/test/typescript/expected/83-closed-world-dispatch.types-oracle b/graph/test/typescript/expected/83-closed-world-dispatch.types-oracle
new file mode 100644
index 000000000..9f55c300b
--- /dev/null
+++ b/graph/test/typescript/expected/83-closed-world-dispatch.types-oracle
@@ -0,0 +1,7 @@
+83-closed-world-dispatch [types]
+  precision 1.0000   (16 correct, 0 wrong)
+  recall    1.0000   (16 of 16 the compiler resolved)
+  sites 18   resolved 17 (94.4%)
+  tiers ambiguous_unknown=1  known_edge=17
+  contexts IMPLEMENTS_INTERFACE=6  METHOD_PARAM=2  METHOD_RETURN=1  OBJECT_CREATION_TYPE=3  SUPER_TYPE=2  TYPE_ELEMENT=4
+  not scored: 1 rows whose target is not a client declaration
diff --git a/graph/test/typescript/run-tests.sh b/graph/test/typescript/run-tests.sh
index ae67e28e8..145cb86bb 100755
--- a/graph/test/typescript/run-tests.sh
+++ b/graph/test/typescript/run-tests.sh
@@ -247,6 +247,14 @@ if ! bash "$HERE/tools/envelope-merge-test.sh"; then
   exit 1
 fi
 PARSER="${AXIOM_PARSER:-$ROOT/parser/dist/index.js}"
+# ── --closed-world on narrows the dispatch fan and records it (#473) ─────────
+# The goldens pin the default (CHA) fan; this solves case 82 with the flag on and checks
+# that exactly the never-constructed implementors drop, each with an assumption row, and
+# that a class built through `new`, through a registry, or through a subclass stays.
+if ! bash "$HERE/tools/closed-world-dispatch-test.sh"; then
+  echo "aborting: --closed-world does not narrow the fan the way it claims"
+  exit 1
+fi
 WORK="$HERE/.work"
 # shellcheck source=../tools/case-pool.sh
 . "$ROOT/graph/test/tools/case-pool.sh"
diff --git a/graph/test/typescript/tools/closed-world-dispatch-test.sh b/graph/test/typescript/tools/closed-world-dispatch-test.sh
new file mode 100644
index 000000000..c7070d159
--- /dev/null
+++ b/graph/test/typescript/tools/closed-world-dispatch-test.sh
@@ -0,0 +1,75 @@
+#!/usr/bin/env bash
+# ─────────────────────────────────────────────────────────────────────────────
+# `--closed-world on` NARROWS THE DISPATCH FAN, AND SAYS SO (#473).
+#
+# By default an interface-typed call fans to every declared implementor (CHA). With the
+# flag the fan is narrowed to the implementors a value the program can build could run
+# (RTA), and every edge the premise removed is exported as a
+# dispatch_assumes_closed_world row. The default is pinned by the ordinary golden of case
+# 83-closed-world-dispatch; this solves the same case with the flag on and checks:
+#
+#   dropped   Unused (named only as a type), Orphan (a subclass nobody constructs),
+#             TypeOnly (imported into another module, but named there only as a type)
+#   KEPT      Built (a `new`), Registered (handed to a registry as a class VALUE — the
+#             DI/factory shape), Base (never constructed, but its body runs on a Leaf),
+#             Provided (imported into another module and handed over as `useClass:` —
+#             the container shape, where the value is an import binding, not the class)
+#   and the assumption file names exactly the three dropped targets, while the flag-off
+#   run writes none.
+# The four kept targets are the controls: each is a way a class is built without the
+# engine seeing a typed `new` of it, and losing any one would be a wrong narrowing.
+# ─────────────────────────────────────────────────────────────────────────────
+set -uo pipefail
+HERE="$(cd "$(dirname "$0")" && pwd)"
+ROOT="$(d="$(cd "$(dirname "$0")" && pwd)"; while [ "$d" != / ] && { [ ! -f "$d/package.json" ] || [ ! -d "$d/graph" ]; }; do d="$(dirname "$d")"; done; echo "$d")"  # the repository root, found by its marker
+PARSER="${AXIOM_PARSER:-$ROOT/parser/dist/index.js}"
+CASE="$HERE/../cases/83-closed-world-dispatch"
+
+fail=0; checks=0
+ok(){  checks=$((checks+1)); return 0; }
+bad(){ checks=$((checks+1)); printf '  FAIL  %s\n' "$1"; fail=1; }
+
+W="$(mktemp -d)"; trap 'rm -rf "$W"' EXIT
+mkdir -p "$W/ir" "$W/empty"
+if ! node "$PARSER" "$CASE/src" cw false "$W/ir" >"$W/parse.log" 2>&1; then
+  echo "  FAIL  parse — see the log below"; sed 's/^/        /' "$W/parse.log" | tail -20
+  echo "closed-world-dispatch: FAILED"; exit 1
+fi
+for mode in off on; do
+  if ! bash "$ROOT/graph/pipeline/run-souffle.sh" --debug --language typescript --closed-world "$mode" \
+       --client-ir "$W/ir" --library "$W/empty" --intermediate "$W/$mode/int" --output "$W/$mode/out" \
+       >"$W/$mode.log" 2>&1; then
+    echo "  FAIL  solve ($mode)"; tail -20 "$W/$mode.log" | sed 's/^/        /'
+    echo "closed-world-dispatch: FAILED"; exit 1
+  fi
+  python3 "$HERE/normalize_edges.py" "$W/ir" "$W/$mode/out/raw" > "$W/$mode.edges"
+done
+
+site='handlers#dispatch(Handler,string) @L42 -> '
+has(){ grep -qF "multi_inferred	METHOD_CALL	$site$2" "$W/$1.edges"; }
+
+kept='Built#handle(string) Registered#handle(string) Base#handle(string) Provided#handle(string)'
+dropped='Unused#handle(string) Orphan#handle(string) TypeOnly#handle(string)'
+for t in $kept $dropped; do
+  has off "$t" && ok || bad "flag off: the CHA fan lost $t — the default must not move"
+done
+for t in $kept; do
+  has on "$t" && ok || bad "flag on: $t was narrowed away, but the program can build a value that runs it"
+done
+for t in $dropped; do
+  has on "$t" && bad "flag on: $t is still in the fan, though nothing constructs it" || ok
+done
+
+gone="$(comm -23 <(sort "$W/off.edges") <(sort "$W/on.edges") | wc -l | tr -d ' ')"
+added="$(comm -13 <(sort "$W/off.edges") <(sort "$W/on.edges") | wc -l | tr -d ' ')"
+[ "$gone" = 3 ] && [ "$added" = 0 ] && ok || bad "flag on moved $gone edge(s) out and $added in; expected exactly the 3 dropped fan edges"
+
+aoff="$W/off/out/raw/assumption-dispatch-closed-world.csv"
+aon="$W/on/out/raw/assumption-dispatch-closed-world.csv"
+[ -f "$aoff" ] && [ ! -s "$aoff" ] && ok || bad "flag off wrote assumption rows (or no file): the default makes no closed-world step"
+n="$(wc -l < "$aon" 2>/dev/null | tr -d ' ')"
+[ "${n:-0}" = 3 ] && ok || bad "flag on wrote ${n:-no} assumption row(s); expected one per dropped edge (3)"
+grep -q "dispatch closed world = on" "$W/on.log" && ok || bad "the solve log does not report the closed-world mode"
+
+if [ "$fail" != 0 ]; then echo "closed-world-dispatch: FAILED ($checks checks)"; exit 1; fi
+echo "closed-world-dispatch: ok ($checks checks)"
diff --git a/graph/typescript/engine/expression-resolution/callee-resolution.dl b/graph/typescript/engine/expression-resolution/callee-resolution.dl
index db0a0bd17..6fe5e6801 100644
--- a/graph/typescript/engine/expression-resolution/callee-resolution.dl
+++ b/graph/typescript/engine/expression-resolution/callee-resolution.dl
@@ -799,6 +799,7 @@ expr_call_dispatch(ce, m) :- call_site("client", _, cn, rk, recv, ce, _),
     !call_super_receiver(ce),
     !dispatch_too_wide(rt, cn),
     implementors(rt, sub),
+    dispatch_admits(sub),
     declared_method_direct(sub, cn, "false", m).
 
 // ── THE STRUCTURAL FAN ──────────────────────────────────────────────────────
@@ -843,6 +844,7 @@ call_super_receiver(ce) :- call_site("client", _, _, "SUPER", _, ce, _).
 dispatch_width(rt, cn, n) :- implementor_member(rt, cn, _),
     n = count : { implementor_member(rt, cn, _) }.
 implementor_member(rt, cn, m) :- implementors(rt, sub),
+    dispatch_admits(sub),
     declared_method_direct(sub, cn, "false", m).
 implementor_member(rt, cn, m) :- structural_implementor(rt, sub),
     declared_method_direct(sub, cn, "false", m).
@@ -851,6 +853,59 @@ dispatch_too_wide(rt, cn) :- dispatch_width(rt, cn, n),
     k = to_number(c),
     n > k.
 
+// ── the closed-world narrowing (#473) — OPT-IN ──────────────────────────────
+// By default the nominal fan is every declared override the hierarchy admits (CHA),
+// bounded only by the cap. With `--closed-world on` it is narrowed to the overrides a
+// value the program can build could run (RTA), which is how Python's self-dispatch is
+// already bounded. The two are different claims under one tier, so the default is
+// unchanged and the narrowed run says it was narrowed: `run.dispatch_closed_world`, and
+// one dispatch_assumes_closed_world row per edge the premise removed.
+//
+// NARROWING IS SOUND ONLY IF EVERY CONSTRUCTION IS VISIBLE, and TypeScript has two
+// common ways to build a class without a `new` the parser can type: a framework or
+// container instantiates a class it was HANDED (`providers: [OrderService]`,
+// `register(Handler)`), and a factory calls `new C()` on a class it received as a
+// value. Both hand the class around as a VALUE, so a class referenced as a value
+// anywhere counts as constructible, alongside every typed `new`. What is left out is a
+// class that is only ever named as a TYPE, or not named at all — the case RTA exists for.
+//
+// A SUBTYPE IS LIVE IF A CONSTRUCTIBLE TYPE CONFORMS TO IT, not only if it is itself
+// constructed: `class Mid { run() {} }` extended by a constructed `Leaf` that does not
+// redeclare `run` executes Mid.run, and dropping Mid would lose an edge a run takes. The
+// conformance closure (not the member-inheritance one) is used so an interface that
+// only a constructed class implements stays in the fan exactly as it is today.
+closed_world_dispatch() :- dispatch_closed_world("on").
+type_constructible(t) :- type_instantiated(t, _).
+type_constructible(t) :- expr_referenced("client", "TYPE", t, _).
+// ...and from ANOTHER module the same value is an IMPORT_BINDING, not a TYPE: a Nest
+// module's `useClass: FileRelationalRepository` names the class it imported. Followed
+// through import_binds directly, not expr_static_type, which sits inside the call
+// resolution this narrowing feeds (dispatch_too_wide negates it: a stratification cycle).
+type_constructible(t) :- expr_referenced("client", "IMPORT_BINDING", ih, _),
+    import_binds(ih, _, "TYPE", t).
+type_live(t) :- type_constructible(t).
+type_live(anc) :- type_constructible(t), type_subtype_star(t, anc).
+type_live(sib) :- type_live(t), scope_sibling(t, sib).
+dispatch_admits(sub) :- implementors(_, sub), !closed_world_dispatch().
+dispatch_admits(sub) :- implementors(_, sub), closed_world_dispatch(), type_live(sub).
+
+// ── dispatch_assumes_closed_world(CallExprHash, DroppedMethodHash) ──────────
+// THE ASSUMPTION IS A ROW, NOT A FOOTNOTE — the counterpart of Python's
+// self_dispatch_assumes_closed_world. Each row is an edge the CHA fan had and the
+// narrowed fan does not, so a consumer can count what the premise cost and restore it
+// for a library whose subclasses live in someone else's code. Empty unless the flag is on.
+dispatch_assumes_closed_world(ce, m) :- closed_world_dispatch(),
+    call_site("client", _, cn, rk, recv, ce, _),
+    receiver_kind_is_value(rk),
+    cn != "",
+    expr_type(recv, _, rt),
+    !call_exact_receiver(ce),
+    !call_super_receiver(ce),
+    !dispatch_too_wide(rt, cn),
+    implementors(rt, sub),
+    !type_live(sub),
+    declared_method_direct(sub, cn, "false", m).
+
 // ── the merged candidate set ────────────────────────────────────────────────
 expr_call_candidate(ce, m) :- expr_call_dispatch(ce, m).
 
diff --git a/graph/typescript/souffle/decls_all.dl b/graph/typescript/souffle/decls_all.dl
index 22d38679a..36d89cb37 100644
--- a/graph/typescript/souffle/decls_all.dl
+++ b/graph/typescript/souffle/decls_all.dl
@@ -97,6 +97,7 @@
 .decl declared_method_direct(c0:symbol,c1:symbol,c2:symbol,c3:symbol)
 .decl demanded_qualified_name(c0:symbol)
 .decl dispatch_cap(c0:symbol)
+.decl dispatch_closed_world(c0:symbol)
 .decl dispatch_too_wide(c0:symbol,c1:symbol)
 .decl dispatch_width(c0:symbol,c1:symbol,c2:number)
 .decl dynamic_import_site(c0:symbol)
@@ -703,3 +704,8 @@
 .decl remote_undetermined(c0:symbol,c1:symbol,c2:symbol)
 .decl remote_unsent(c0:symbol,c1:symbol,c2:symbol)
 .decl remote_unserved(c0:symbol,c1:symbol,c2:symbol)
+.decl closed_world_dispatch()
+.decl dispatch_admits(c0:symbol)
+.decl dispatch_assumes_closed_world(c0:symbol,c1:symbol)
+.decl type_constructible(c0:symbol)
+.decl type_live(c0:symbol)
diff --git a/graph/typescript/souffle/export_manifest.tsv b/graph/typescript/souffle/export_manifest.tsv
index 23b265dfb..f319cddf5 100644
--- a/graph/typescript/souffle/export_manifest.tsv
+++ b/graph/typescript/souffle/export_manifest.tsv
@@ -54,3 +54,4 @@ remote_edge	remote-edge.csv
 remote_unserved	remote-unserved.csv
 remote_unsent	remote-unsent.csv
 remote_undetermined	remote-undetermined.csv
+dispatch_assumes_closed_world	assumption-dispatch-closed-world.csv