diff --git a/selfhost/cmd/w6c/main.combined.ww b/selfhost/cmd/w6c/main.combined.ww
index d7b62c49..d51948d5 100644
--- a/selfhost/cmd/w6c/main.combined.ww
+++ b/selfhost/cmd/w6c/main.combined.ww
@@ -8663,6 +8663,32 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 				};
 			};
 		};
+		// len(x) / append(s,...) / free(p) — Hare pseudo-builtins.
+		// Mirror cstage cmd/wcc/check.c:896-1011 (rule 10 requires
+		// stage byte-id; both stages stamp the same shape). No shadow
+		// guard: cstage's len/append/free intercepts have none either
+		// (check.c:901/962/1005), and the names are seeded into c.top
+		// at L85-88 so a user same-module decl dup-silences. Harec
+		// models these as dedicated AST kinds — EXPR_LEN at
+		// ref/harec/src/check.c:2630 (result `&builtin_type_size`),
+		// EXPR_APPEND at :745 (result `(nomem | void)`), EXPR_FREE at
+		// :2443 (result `&builtin_type_void`). The cstage divergence
+		// (len → i32 not size, append → void not tagged) pre-dates
+		// this task; #19 (Drew's δ — dedicated AST kinds) is the
+		// Hare-faithful path. This is the intercept-shim minimum to
+		// unblock #15 (A.6.2.1e assertion enable).
+		if (callee.kind == nkind.N_IDENT) {
+			if (streq(callee.str, "len")) {
+				let tn: *node = mktname(c, "i32");
+				e.type_ = tinfofornode(c, tn): *void;
+				return tn;
+			};
+			if (streq(callee.str, "append") || streq(callee.str, "free")) {
+				let tn: *node = mktname(c, "void");
+				e.type_ = tinfofornode(c, tn): *void;
+				return tn;
+			};
+		};
 		let nm: str;
 		nm.ptr = nil; nm.len = 0;
 		if (callee.kind == nkind.N_IDENT) { nm = callee.str; };
diff --git a/selfhost/cmd/wcc/check.ww b/selfhost/cmd/wcc/check.ww
index 4e8e6a73..cf1e2e94 100644
--- a/selfhost/cmd/wcc/check.ww
+++ b/selfhost/cmd/wcc/check.ww
@@ -1699,6 +1699,32 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 				};
 			};
 		};
+		// len(x) / append(s,...) / free(p) — Hare pseudo-builtins.
+		// Mirror cstage cmd/wcc/check.c:896-1011 (rule 10 requires
+		// stage byte-id; both stages stamp the same shape). No shadow
+		// guard: cstage's len/append/free intercepts have none either
+		// (check.c:901/962/1005), and the names are seeded into c.top
+		// at L85-88 so a user same-module decl dup-silences. Harec
+		// models these as dedicated AST kinds — EXPR_LEN at
+		// ref/harec/src/check.c:2630 (result `&builtin_type_size`),
+		// EXPR_APPEND at :745 (result `(nomem | void)`), EXPR_FREE at
+		// :2443 (result `&builtin_type_void`). The cstage divergence
+		// (len → i32 not size, append → void not tagged) pre-dates
+		// this task; #19 (Drew's δ — dedicated AST kinds) is the
+		// Hare-faithful path. This is the intercept-shim minimum to
+		// unblock #15 (A.6.2.1e assertion enable).
+		if (callee.kind == nkind.N_IDENT) {
+			if (streq(callee.str, "len")) {
+				let tn: *node = mktname(c, "i32");
+				e.type_ = tinfofornode(c, tn): *void;
+				return tn;
+			};
+			if (streq(callee.str, "append") || streq(callee.str, "free")) {
+				let tn: *node = mktname(c, "void");
+				e.type_ = tinfofornode(c, tn): *void;
+				return tn;
+			};
+		};
 		let nm: str;
 		nm.ptr = nil; nm.len = 0;
 		if (callee.kind == nkind.N_IDENT) { nm = callee.str; };
diff --git a/selfhost/cmd/wwdump/main.combined.ww b/selfhost/cmd/wwdump/main.combined.ww
index 522d2841..6cedc0eb 100644
--- a/selfhost/cmd/wwdump/main.combined.ww
+++ b/selfhost/cmd/wwdump/main.combined.ww
@@ -8663,6 +8663,32 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 				};
 			};
 		};
+		// len(x) / append(s,...) / free(p) — Hare pseudo-builtins.
+		// Mirror cstage cmd/wcc/check.c:896-1011 (rule 10 requires
+		// stage byte-id; both stages stamp the same shape). No shadow
+		// guard: cstage's len/append/free intercepts have none either
+		// (check.c:901/962/1005), and the names are seeded into c.top
+		// at L85-88 so a user same-module decl dup-silences. Harec
+		// models these as dedicated AST kinds — EXPR_LEN at
+		// ref/harec/src/check.c:2630 (result `&builtin_type_size`),
+		// EXPR_APPEND at :745 (result `(nomem | void)`), EXPR_FREE at
+		// :2443 (result `&builtin_type_void`). The cstage divergence
+		// (len → i32 not size, append → void not tagged) pre-dates
+		// this task; #19 (Drew's δ — dedicated AST kinds) is the
+		// Hare-faithful path. This is the intercept-shim minimum to
+		// unblock #15 (A.6.2.1e assertion enable).
+		if (callee.kind == nkind.N_IDENT) {
+			if (streq(callee.str, "len")) {
+				let tn: *node = mktname(c, "i32");
+				e.type_ = tinfofornode(c, tn): *void;
+				return tn;
+			};
+			if (streq(callee.str, "append") || streq(callee.str, "free")) {
+				let tn: *node = mktname(c, "void");
+				e.type_ = tinfofornode(c, tn): *void;
+				return tn;
+			};
+		};
 		let nm: str;
 		nm.ptr = nil; nm.len = 0;
 		if (callee.kind == nkind.N_IDENT) { nm = callee.str; };