diff --git a/pkg/urbit/include/all.h b/pkg/urbit/include/all.h
index b138c6d408..ae647d865a 100644
--- a/pkg/urbit/include/all.h
+++ b/pkg/urbit/include/all.h
@@ -1,7 +1,3 @@
-/* include/all.h
-**
-** This file is in the public domain.
-*/
 #   include "config.h"
   /** c3: C environment.
   **/
diff --git a/pkg/urbit/include/c/defs.h b/pkg/urbit/include/c/defs.h
index 8dda9b126e..245bfcf2fc 100644
--- a/pkg/urbit/include/c/defs.h
+++ b/pkg/urbit/include/c/defs.h
@@ -1,7 +1,6 @@
-/* include/c/defs.h
-**
-** This file is in the public domain.
-*/
+#ifndef C3_DEFS_H
+#define C3_DEFS_H
+
   /** Loobeans - inverse booleans to match nock.
   **/
 #     define c3y      0
@@ -122,3 +121,5 @@
           c3_assert(!"memory lost");                            \
         }                                                       \
         rut;})
+
+#endif /* ifndef C3_DEFS_H */
diff --git a/pkg/urbit/include/c/motes.h b/pkg/urbit/include/c/motes.h
index 789fd209f8..cda80b557f 100644
--- a/pkg/urbit/include/c/motes.h
+++ b/pkg/urbit/include/c/motes.h
@@ -1,7 +1,6 @@
-/* include/lib/motes.h
-**
-** This file is in the public domain.
-*/
+#ifndef C3_MOTES_H
+#define C3_MOTES_H
+
   /** Definitions.
   **/
 
@@ -1313,3 +1312,5 @@
 #   define c3__zpzp   c3_s4('z','p','z','p')
 #   define c3__zuse   c3_s4('z','u','s','e')
 #   define c3__zush   c3_s4('z','u','s','h')
+
+#endif /* ifndef C3_MOTES_H */
diff --git a/pkg/urbit/include/c/portable.h b/pkg/urbit/include/c/portable.h
index f3edc95b44..0f082ccada 100644
--- a/pkg/urbit/include/c/portable.h
+++ b/pkg/urbit/include/c/portable.h
@@ -1,7 +1,5 @@
-/* include/c/portable.h
-**
-** This file is in the public domain.
-*/
+#ifndef C3_PORTABLE_H
+#define C3_PORTABLE_H
 
 #include "config.h"
 
@@ -242,3 +240,5 @@
 #     define ASSERT_CONCAT(a, b) ASSERT_CONCAT_(a, b)
 #     define STATIC_ASSERT(e,m) \
         ;enum { ASSERT_CONCAT(assert_line_, __LINE__) = 1/(int)(!!(e)) }
+
+#endif /* ifndef C3_PORTABLE_H */
diff --git a/pkg/urbit/include/c/types.h b/pkg/urbit/include/c/types.h
index a7d74901cd..b333ff1158 100644
--- a/pkg/urbit/include/c/types.h
+++ b/pkg/urbit/include/c/types.h
@@ -1,7 +1,6 @@
-/* include/c/types.h
-**
-** This file is in the public domain.
-*/
+#ifndef C3_TYPES_H
+#define C3_TYPES_H
+
   /** Integer typedefs.
   **/
     /* Canonical integers.
@@ -28,3 +27,5 @@
       typedef int       c3_i;      // int - really bad
       typedef uintptr_t c3_p;      // pointer-length uint - really really bad
       typedef intptr_t c3_ps;      // pointer-length int - really really bad
+
+#endif /* ifndef C3_TYPES_H */
diff --git a/pkg/urbit/include/jets/g.h b/pkg/urbit/include/jets/g.h
deleted file mode 100644
index aa0731f1c0..0000000000
--- a/pkg/urbit/include/jets/g.h
+++ /dev/null
@@ -1,264 +0,0 @@
-/* include/f/qjet.h
-**
-** This file is in the public domain.
-*/
-  /** Tier 1.
-  **/
-    u3_noun u3ga_add(u3_atom, u3_atom);
-    u3_noun u3ga_dec(u3_atom);
-    u3_noun u3ga_div(u3_atom, u3_atom);
-    u3_noun u3ga_gte(u3_atom, u3_atom);
-    u3_noun u3ga_gth(u3_atom, u3_atom);
-    u3_noun u3ga_inc(u3_atom);
-    u3_noun u3ga_lte(u3_atom, u3_atom);
-    u3_noun u3ga_lth(u3_atom, u3_atom);
-    u3_noun u3ga_mod(u3_atom, u3_atom);
-    u3_noun u3ga_mul(u3_atom, u3_atom);
-    u3_noun u3ga_sub(u3_atom, u3_atom);
-
-  /** Tier 2.
-  **/
-    u3_noun u3gb_bind(u3_noun, u3_noun);
-    u3_noun u3gb_clap(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gb_drop(u3_noun);
-    u3_noun u3gb_flop(u3_noun);
-    u3_noun u3gb_lent(u3_noun);
-    u3_noun u3gb_levy(u3_noun, u3_noun);
-    u3_noun u3gb_lien(u3_noun, u3_noun);
-    u3_noun u3gb_murn(u3_noun, u3_noun);
-    u3_noun u3gb_need(u3_noun);
-    u3_noun u3gb_reap(u3_atom, u3_noun);
-    u3_noun u3gb_reel(u3_noun, u3_noun);
-    u3_noun u3gb_roll(u3_noun, u3_noun);
-    u3_noun u3gb_skid(u3_noun, u3_noun);
-    u3_noun u3gb_skim(u3_noun, u3_noun);
-    u3_noun u3gb_skip(u3_noun, u3_noun);
-    u3_noun u3gb_scag(u3_atom, u3_noun);
-    u3_noun u3gb_slag(u3_atom, u3_noun);
-    u3_noun u3gb_snag(u3_atom, u3_noun);
-    u3_noun u3gb_sort(u3_noun, u3_noun);
-    u3_noun u3gb_turn(u3_noun, u3_noun);
-    u3_noun u3gb_weld(u3_noun, u3_noun);
-
-  /** Tier 3.
-  **/
-    u3_noun u3gc_bex(u3_atom);
-    u3_noun u3gc_xeb(u3_atom);
-    u3_noun u3gc_can(u3_atom, u3_noun);
-    u3_noun u3gc_cap(u3_atom);
-    u3_noun u3gc_cat(u3_atom, u3_atom, u3_atom);
-    u3_noun u3gc_con(u3_atom, u3_atom);
-    u3_noun u3gc_cut(u3_atom, u3_atom, u3_atom, u3_atom);
-    u3_noun u3gc_dis(u3_atom, u3_atom);
-    u3_noun u3gc_dor(u3_atom, u3_atom);
-    u3_noun u3gc_dvr(u3_atom, u3_atom);
-    u3_noun u3gc_end(u3_atom, u3_atom, u3_atom);
-    u3_noun u3gc_gor(u3_atom, u3_atom);
-    u3_noun u3gc_hor(u3_atom, u3_atom);
-    u3_noun u3gc_lsh(u3_atom, u3_atom, u3_atom);
-    u3_noun u3gc_mas(u3_atom);
-    u3_noun u3gc_met(u3_atom, u3_atom);
-    u3_noun u3gc_mix(u3_atom, u3_atom);
-    u3_noun u3gc_muk(u3_atom, u3_atom, u3_atom);
-    u3_noun u3gc_peg(u3_atom, u3_atom);
-    u3_noun u3gc_pow(u3_atom, u3_atom);
-    u3_noun u3gc_rap(u3_atom, u3_noun);
-    u3_noun u3gc_rep(u3_atom, u3_noun);
-    u3_noun u3gc_rip(u3_atom, u3_atom);
-    u3_noun u3gc_rsh(u3_atom, u3_atom, u3_atom);
-    u3_noun u3gc_sqt(u3_atom);
-    u3_noun u3gc_vor(u3_atom, u3_atom);
-
-  /** Tier 4.
-  **/
-    u3_noun u3gdb_bif(u3_noun, u3_noun);
-    u3_noun u3gdb_dif(u3_noun, u3_noun);
-    u3_noun u3gdb_gas(u3_noun, u3_noun);
-    u3_noun u3gdb_get(u3_noun, u3_noun);
-    u3_noun u3gdb_has(u3_noun, u3_noun);
-    u3_noun u3gdb_int(u3_noun, u3_noun);
-    u3_noun u3gdb_put(u3_noun, u3_noun, u3_noun);
-#   define u3gdb_tap u3gdi_tap
-    u3_noun u3gdb_uni(u3_noun, u3_noun);
-
-    u3_noun u3gdi_bif(u3_noun, u3_noun);
-    u3_noun u3gdi_dif(u3_noun, u3_noun);
-    u3_noun u3gdi_gas(u3_noun, u3_noun);
-    u3_noun u3gdi_has(u3_noun, u3_noun);
-    u3_noun u3gdi_int(u3_noun, u3_noun);
-    u3_noun u3gdi_mer(u3_noun, u3_noun);
-    u3_noun u3gdi_put(u3_noun, u3_noun);
-    u3_noun u3gdi_tap(u3_noun);
-    u3_noun u3gdi_uni(u3_noun, u3_noun);
-    u3_noun u3gdi_wyt(u3_noun);
-
-  /** Tier 5.
-  **/
-    u3_noun u3ge_cue(u3_atom);
-    u3_noun u3ge_jam(u3_atom);
-    u3_noun u3ge_mat(u3_atom);
-    u3_noun u3ge_rub(u3_atom, u3_atom);
-    u3_noun u3ge_lore(u3_atom);
-    u3_noun u3ge_loss(u3_noun, u3_noun);
-    u3_noun u3ge_lune(u3_atom);
-    u3_noun u3ge_repg(u3_noun, u3_noun, u3_noun);
-    u3_noun u3ge_rexp(u3_noun, u3_noun);
-    u3_noun u3ge_trip(u3_atom);
-
-    u3_noun u3gea_ecba_en(u3_atom, u3_atom);
-    u3_noun u3gea_ecba_de(u3_atom, u3_atom);
-    u3_noun u3gea_ecbb_en(u3_atom, u3_atom);
-    u3_noun u3gea_ecbb_de(u3_atom, u3_atom);
-    u3_noun u3gea_ecbc_en(u3_atom, u3_atom);
-    u3_noun u3gea_ecbc_de(u3_atom, u3_atom);
-
-    u3_noun u3gea_cbca_en(u3_atom, u3_atom, u3_atom);
-    u3_noun u3gea_cbca_de(u3_atom, u3_atom, u3_atom);
-    u3_noun u3gea_cbcb_en(u3_atom, u3_atom, u3_atom);
-    u3_noun u3gea_cbcb_de(u3_atom, u3_atom, u3_atom);
-    u3_noun u3gea_cbcc_en(u3_atom, u3_atom, u3_atom);
-    u3_noun u3gea_cbcc_de(u3_atom, u3_atom, u3_atom);
-
-    u3_noun u3gea_de(u3_atom, u3_atom);
-    u3_noun u3gea_en(u3_atom, u3_atom);
-
-    u3_noun u3ges_hsh(u3_atom, u3_atom, u3_atom, u3_atom, u3_atom, u3_atom);
-    u3_noun u3ges_hsl(u3_atom, u3_atom, u3_atom, u3_atom, u3_atom,
-                      u3_atom, u3_atom, u3_atom);
-    u3_noun u3ges_pbk(u3_atom, u3_atom, u3_atom, u3_atom);
-    u3_noun u3ges_pbl(u3_atom, u3_atom, u3_atom, u3_atom, u3_atom, u3_atom);
-
-    u3_noun u3ge_shax(u3_atom);
-    u3_noun u3ge_shay(u3_atom, u3_atom);
-    u3_noun u3ge_shas(u3_atom, u3_atom);
-    u3_noun u3ge_shal(u3_atom, u3_atom);
-
-    u3_noun u3geo_raw(u3_atom, u3_atom);
-
-    u3_noun u3gef_drg(u3_noun, u3_atom);
-    u3_noun u3gef_lug(u3_noun, u3_noun, u3_atom, u3_atom);
-
-    u3_noun u3ger_add(u3_atom, u3_atom, u3_atom);
-    u3_noun u3ger_sub(u3_atom, u3_atom, u3_atom);
-    u3_noun u3ger_mul(u3_atom, u3_atom, u3_atom);
-    u3_noun u3ger_div(u3_atom, u3_atom, u3_atom);
-    u3_noun u3ger_sqt(u3_atom, u3_atom);
-    u3_noun u3ger_fma(u3_atom, u3_atom, u3_atom, u3_atom);
-    u3_noun u3ger_lth(u3_atom, u3_atom);
-    u3_noun u3ger_lte(u3_atom, u3_atom);
-    u3_noun u3ger_equ(u3_atom, u3_atom);
-    u3_noun u3ger_gte(u3_atom, u3_atom);
-    u3_noun u3ger_gth(u3_atom, u3_atom);
-
-    u3_noun u3get_add(u3_atom, u3_atom, u3_atom);
-    u3_noun u3get_sub(u3_atom, u3_atom, u3_atom);
-    u3_noun u3get_mul(u3_atom, u3_atom, u3_atom);
-    u3_noun u3get_div(u3_atom, u3_atom, u3_atom);
-    u3_noun u3get_sqt(u3_atom, u3_atom);
-    u3_noun u3get_fma(u3_atom, u3_atom, u3_atom, u3_atom);
-    u3_noun u3get_lth(u3_atom, u3_atom);
-    u3_noun u3get_lte(u3_atom, u3_atom);
-    u3_noun u3get_equ(u3_atom, u3_atom);
-    u3_noun u3get_gte(u3_atom, u3_atom);
-    u3_noun u3get_gth(u3_atom, u3_atom);
-
-    u3_noun u3geq_add(u3_atom, u3_atom, u3_atom);
-    u3_noun u3geq_sub(u3_atom, u3_atom, u3_atom);
-    u3_noun u3geq_mul(u3_atom, u3_atom, u3_atom);
-    u3_noun u3geq_div(u3_atom, u3_atom, u3_atom);
-    u3_noun u3geq_sqt(u3_atom, u3_atom);
-    u3_noun u3geq_fma(u3_atom, u3_atom, u3_atom, u3_atom);
-    u3_noun u3geq_lth(u3_atom, u3_atom);
-    u3_noun u3geq_lte(u3_atom, u3_atom);
-    u3_noun u3geq_equ(u3_atom, u3_atom);
-    u3_noun u3geq_gte(u3_atom, u3_atom);
-    u3_noun u3geq_gth(u3_atom, u3_atom);
-
-    u3_noun u3ges_add(u3_atom, u3_atom, u3_atom);
-    u3_noun u3ges_sub(u3_atom, u3_atom, u3_atom);
-    u3_noun u3ges_mul(u3_atom, u3_atom, u3_atom);
-    u3_noun u3ges_div(u3_atom, u3_atom, u3_atom);
-    u3_noun u3ges_sqt(u3_atom, u3_atom);
-    u3_noun u3ges_fma(u3_atom, u3_atom, u3_atom, u3_atom);
-    u3_noun u3ges_lth(u3_atom, u3_atom);
-    u3_noun u3ges_lte(u3_atom, u3_atom);
-    u3_noun u3ges_equ(u3_atom, u3_atom);
-    u3_noun u3ges_gte(u3_atom, u3_atom);
-    u3_noun u3ges_gth(u3_atom, u3_atom);
-
-  /** Tier 6.
-  **/
-    u3_noun u3gf_bull(u3_noun, u3_noun);
-    u3_noun u3gf_cell(u3_noun, u3_noun);
-    u3_noun u3gf_comb(u3_noun, u3_noun);
-    u3_noun u3gf_cons(u3_noun, u3_noun);
-    u3_noun u3gf_core(u3_noun, u3_noun);
-    u3_noun u3gf_cube(u3_noun, u3_noun);
-    u3_noun u3gf_face(u3_noun, u3_noun);
-    u3_noun u3gf_fine(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gf_fitz(u3_noun, u3_noun);
-    u3_noun u3gf_flan(u3_noun, u3_noun);
-    u3_noun u3gf_flay(u3_noun);
-    u3_noun u3gf_flip(u3_noun);
-    u3_noun u3gf_flor(u3_noun, u3_noun);
-    u3_noun u3gf_forq(u3_noun, u3_noun);
-    u3_noun u3gf_fork(u3_noun);
-    u3_noun u3gf_grof(u3_noun);
-    u3_noun u3gf_help(u3_noun, u3_noun);
-    u3_noun u3gf_hike(u3_noun, u3_noun);
-    u3_noun u3gf_look(u3_noun, u3_noun);
-    u3_noun u3gf_loot(u3_noun, u3_noun);
-    u3_noun u3gf_slot(u3_atom, u3_noun);
-    u3_noun u3gf_type(u3_noun);
-
-    u3_noun u3gfl_bunt(u3_noun, u3_noun);
-    u3_noun u3gfl_whip(u3_noun, u3_noun, u3_noun);
-
-    u3_noun u3gfp_hack(u3_noun, u3_noun);
-    u3_noun u3gfp_late(u3_noun);
-    u3_noun u3gfp_open(u3_noun, u3_noun);
-    u3_noun u3gfp_rake(u3_noun);
-
-#   define u3gfu_van_fan  28
-#   define u3gfu_van_rib  58
-#   define u3gfu_van_vrf  59
-#   define u3gfu_van_vet  118
-#   define u3gfu_van_fab  119
-
-    u3_noun u3gfu_burn(u3_noun, u3_noun);
-    u3_noun u3gfu_busk(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_buss(u3_noun, u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_bust(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_crop(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_cull(u3_noun, u3_noun, u3_noun, u3_atom, u3_noun);
-    u3_noun u3gfu_duck(u3_noun, u3_noun);
-    u3_noun u3gfu_dung(u3_noun, u3_noun cap, u3_noun);
-    u3_noun u3gfu_dunq(u3_noun, const c3_c*, u3_noun);
-    void    u3gfu_dump(u3_noun, const c3_c*, u3_noun);
-    u3_noun u3gfu_fond(u3_noun, u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_finc(u3_noun, u3_noun, u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_fink(u3_noun, u3_noun, u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_fire(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_firm(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_fish(u3_noun, u3_noun, u3_atom);
-    u3_noun u3gfu_fuse(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_gain(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_heal(u3_noun, u3_noun, u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_lose(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_mint(u3_noun, u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_mull(u3_noun, u3_noun, u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_nest(u3_noun, u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_nost(u3_noun, u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_orth(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_peek(u3_noun, u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_peel(u3_noun, u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_play(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_repo(u3_noun, u3_noun);
-    u3_noun u3gfu_rest(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_shep(u3_noun, const c3_c*, u3_noun, u3_noun);
-    u3_noun u3gfu_shew(u3_noun, u3_noun);
-    u3_noun u3gfu_sift(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_snub(u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_tack(u3_noun, u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_toss(u3_noun, u3_noun, u3_noun, u3_noun, u3_noun);
-    u3_noun u3gfu_wrap(u3_noun, u3_noun, u3_noun);
diff --git a/pkg/urbit/include/jets/k.h b/pkg/urbit/include/jets/k.h
index 1f15a3866c..f8cce61cf8 100644
--- a/pkg/urbit/include/jets/k.h
+++ b/pkg/urbit/include/jets/k.h
@@ -1,7 +1,6 @@
-/* include/f/kjet.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_JETS_K_H
+#define U3_JETS_K_H
+
   /** Tier 1.
   **/
     u3_noun u3ka_add(u3_noun a, u3_noun b);
@@ -161,3 +160,5 @@
   */
     u3_noun
     u3kfu_repo(u3_noun, u3_noun);
+
+#endif /* ifndef U3_JETS_K_H */
diff --git a/pkg/urbit/include/jets/l.h b/pkg/urbit/include/jets/l.h
deleted file mode 100644
index e242ef6712..0000000000
--- a/pkg/urbit/include/jets/l.h
+++ /dev/null
@@ -1,115 +0,0 @@
-/* include/f/kjet.h
-**
-** This file is in the public domain.
-*/
-  /** Tier 1.
-  **/
-    u3_noun u3la_add(u3_noun a, u3_noun b);
-    u3_noun u3la_sub(u3_noun a, u3_noun b);
-    u3_noun u3la_mul(u3_noun a, u3_noun b);
-    u3_noun u3la_gth(u3_noun a, u3_noun b);
-    u3_noun u3la_lte(u3_noun a, u3_noun b);
-
-  /** Tier 2.
-  **/
-    u3_noun u3lb_lent(u3_noun a);
-    u3_noun u3lb_weld(u3_noun a, u3_noun b);
-    u3_noun u3lb_flop(u3_noun a);
-
-/* u3lc: tier 3 functions
-*/
-  /* u3lc_lsh(): left shift.
-  */
-    u3_noun
-    u3lc_lsh(u3_noun a, u3_noun b, u3_noun c);
-
-  /* u3lc_rsh(): right shift.
-  */
-    u3_noun
-    u3lc_rsh(u3_noun a, u3_noun b, u3_noun c);
-
-/* u3ld: tier 4 functions
-*/
-  /* u3ldb_get(): map get for key `b` in map `a` with u3_none.
-  */
-    u3_weak
-    u3ldb_get(u3_noun a, u3_noun b);
-
-  /* u3ldb_got(): map get for key `b` in map `a` with bail.
-  */
-    u3_noun
-    u3ldb_got(u3_noun a, u3_noun b);
-
-  /* u3ldb_put(): map put for key `b`, value `c` in map `a`.
-  */
-    u3_weak
-    u3ldb_put(u3_noun a, u3_noun b, u3_noun c);
-
-  /* u3ldb_has(): test for get.
-  */
-    u3_noun
-    u3ldb_has(u3_noun a, u3_noun b);
-
-  /* u3ldb_gas(): list to map.
-  */
-    u3_noun
-    u3ldb_gas(u3_noun a, u3_noun b);
-
-  /* u3ldi_gas(): list to map.
-  */
-    u3_noun
-    u3ldi_gas(u3_noun a, u3_noun b);
-
-  /* u3ldi_has(): test for presence.
-  */
-    u3_noun
-    u3ldi_has(u3_noun a, u3_noun b);
-
-  /* u3ldi_tap(): map/set convert to list.  (solves by_tap also.)
-  */
-    u3_noun
-    u3ldi_tap(u3_noun a);
-
-  /* u3ldi_put(): put in set.
-  */
-    u3_weak
-    u3ldi_put(u3_noun a, u3_noun b);
-
-  /* u3ldi_uni(): set union.
-  */
-    u3_noun
-    u3ldi_uni(u3_noun a, u3_noun b);
-
-#   define u3ldb_tap(a) u3ldi_tap(a)
-
-/* u3le: tier 5 functions
-*/
-  /* u3le_cue(): expand saved pill.
-  */
-    u3_noun
-    u3le_cue(u3_atom a);
-
-  /* u3le_jam(): pack noun as atom.
-  */
-    u3_atom
-    u3le_jam(u3_noun a);
-
-  /* u3le_trip(): atom to tape.
-  */
-    u3_noun
-    u3le_trip(u3_noun a);
-
-  /* u3lf_fork(): build %fork span.
-  */
-    u3_noun
-    u3lf_fork(u3_noun yed);
-
-  /* u3kz_fork(): build %fork span.
-  */
-    u3_noun
-    u3kz_fork(u3_noun yed);
-
-  /* u3lfu_repo():
-  */
-    u3_noun
-    u3lfu_repo(u3_noun, u3_noun);
diff --git a/pkg/urbit/include/jets/q.h b/pkg/urbit/include/jets/q.h
index 0f83cf3817..305164fb89 100644
--- a/pkg/urbit/include/jets/q.h
+++ b/pkg/urbit/include/jets/q.h
@@ -1,7 +1,6 @@
-/* include/f/qjet.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_JETS_Q_H
+#define U3_JETS_Q_H
+
   /** Tier 1.
   **/
     u3_noun u3qa_add(u3_atom, u3_atom);
@@ -241,3 +240,5 @@
 #   define u3qfu_van_vet  59
 
     void u3qf_test(const c3_c*, u3_noun);
+
+#endif /* ifndef U3_JETS_Q_H */
diff --git a/pkg/urbit/include/jets/w.h b/pkg/urbit/include/jets/w.h
index 4cc8473433..a3cbedd785 100644
--- a/pkg/urbit/include/jets/w.h
+++ b/pkg/urbit/include/jets/w.h
@@ -1,7 +1,6 @@
-/* include/f/qjet.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_JETS_W_H
+#define U3_JETS_W_H
+
   /** Tier 1.
   **/
     u3_noun u3wa_add(u3_noun);
@@ -318,3 +317,5 @@
     u3_noun u3wfu_play(u3_noun);
     u3_noun u3wfu_repo(u3_noun);
     u3_noun u3wfu_rest(u3_noun);
+
+#endif /* ifndef U3_JETS_W_H */
diff --git a/pkg/urbit/include/jets/y.h b/pkg/urbit/include/jets/y.h
deleted file mode 100644
index de009619fd..0000000000
--- a/pkg/urbit/include/jets/y.h
+++ /dev/null
@@ -1,328 +0,0 @@
-/* include/f/qjet.h
-**
-** This file is in the public domain.
-*/
-  /** Tier 1.
-  **/
-    u3_noun u3ya_add(u3_noun);
-    u3_noun u3ya_dec(u3_noun);
-    u3_noun u3ya_div(u3_noun);
-    u3_noun u3ya_gte(u3_noun);
-    u3_noun u3ya_gth(u3_noun);
-    u3_noun u3ya_lte(u3_noun);
-    u3_noun u3ya_lth(u3_noun);
-    u3_noun u3ya_mod(u3_noun);
-    u3_noun u3ya_mul(u3_noun);
-    u3_noun u3ya_sub(u3_noun);
-
-  /** Tier 2.
-  **/
-    u3_noun u3yb_bind(u3_noun);
-    u3_noun u3yb_clap(u3_noun);
-    u3_noun u3yb_drop(u3_noun);
-    u3_noun u3yb_flop(u3_noun);
-    u3_noun u3yb_lent(u3_noun);
-    u3_noun u3yb_levy(u3_noun);
-    u3_noun u3yb_lien(u3_noun);
-    u3_noun u3yb_murn(u3_noun);
-    u3_noun u3yb_need(u3_noun);
-    u3_noun u3yb_reap(u3_noun);
-    u3_noun u3yb_reel(u3_noun);
-    u3_noun u3yb_roll(u3_noun);
-    u3_noun u3yb_skid(u3_noun);
-    u3_noun u3yb_skim(u3_noun);
-    u3_noun u3yb_skip(u3_noun);
-    u3_noun u3yb_scag(u3_noun);
-    u3_noun u3yb_slag(u3_noun);
-    u3_noun u3yb_snag(u3_noun);
-    u3_noun u3yb_sort(u3_noun);
-    u3_noun u3yb_turn(u3_noun);
-    u3_noun u3yb_weld(u3_noun);
-
-  /** Tier 3.
-  **/
-    u3_noun u3yc_bex(u3_noun);
-    u3_noun u3yc_xeb(u3_noun);
-    u3_noun u3yc_can(u3_noun);
-    u3_noun u3yc_cap(u3_noun);
-    u3_noun u3yc_cat(u3_noun);
-    u3_noun u3yc_con(u3_noun);
-    u3_noun u3yc_cut(u3_noun);
-    u3_noun u3yc_dis(u3_noun);
-    u3_noun u3yc_dor(u3_noun);
-    u3_noun u3yc_dvr(u3_noun);
-    u3_noun u3yc_end(u3_noun);
-    u3_noun u3yc_gor(u3_noun);
-    u3_noun u3yc_hor(u3_noun);
-    u3_noun u3yc_lsh(u3_noun);
-    u3_noun u3yc_mas(u3_noun);
-    u3_noun u3yc_met(u3_noun);
-    u3_noun u3yc_mix(u3_noun);
-    u3_noun u3yc_mug(u3_noun);
-    u3_noun u3yc_muk(u3_noun);
-    u3_noun u3yc_peg(u3_noun);
-    u3_noun u3yc_pow(u3_noun);
-    u3_noun u3yc_rap(u3_noun);
-    u3_noun u3yc_rep(u3_noun);
-    u3_noun u3yc_rip(u3_noun);
-    u3_noun u3yc_rsh(u3_noun);
-    u3_noun u3yc_sqt(u3_noun);
-    u3_noun u3yc_vor(u3_noun);
-
-    u3_noun u3ycp_ins(u3_noun);
-    u3_noun u3ycp_ind(u3_noun);
-    u3_noun u3ycp_tos(u3_noun);
-    u3_noun u3ycp_tod(u3_noun);
-
-  /** Tier 4.
-  **/
-    u3_noun u3ydb_bif(u3_noun);
-    u3_noun u3ydb_dif(u3_noun);
-    u3_noun u3ydb_gas(u3_noun);
-    u3_noun u3ydb_get(u3_noun);
-    u3_noun u3ydb_has(u3_noun);
-    u3_noun u3ydb_int(u3_noun);
-    u3_noun u3ydb_put(u3_noun);
-#   define u3ydb_tap u3ydi_tap
-    u3_noun u3ydb_uni(u3_noun);
-
-    u3_noun u3ydi_bif(u3_noun);
-    u3_noun u3ydi_dif(u3_noun);
-    u3_noun u3ydi_gas(u3_noun);
-    u3_noun u3ydi_has(u3_noun);
-    u3_noun u3ydi_int(u3_noun);
-    u3_noun u3ydi_mer(u3_noun);
-    u3_noun u3ydi_put(u3_noun);
-    u3_noun u3ydi_tap(u3_noun);
-    u3_noun u3ydi_uni(u3_noun);
-    u3_noun u3ydi_wyt(u3_noun);
-
-  /** Tier 5.
-  **/
-    u3_noun u3ye_cue(u3_noun);
-    u3_noun u3ye_jam(u3_noun);
-    u3_noun u3ye_mat(u3_noun);
-    u3_noun u3ye_rub(u3_noun);
-    u3_noun u3ye_lore(u3_noun);
-    u3_noun u3ye_loss(u3_noun);
-    u3_noun u3ye_lune(u3_noun);
-    u3_noun u3ye_mink(u3_noun);
-    u3_noun u3ye_mule(u3_noun);
-    u3_noun u3ye_repg(u3_noun);
-    u3_noun u3ye_rexp(u3_noun);
-    u3_noun u3ye_trip(u3_noun);
-
-    u3_noun u3ye_pfix(u3_noun);
-    u3_noun u3ye_plug(u3_noun);
-    u3_noun u3ye_pose(u3_noun);
-    u3_noun u3ye_sfix(u3_noun);
-
-    u3_noun u3yea_ecba_en(u3_noun);
-    u3_noun u3yea_ecba_de(u3_noun);
-    u3_noun u3yea_ecbb_en(u3_noun);
-    u3_noun u3yea_ecbb_de(u3_noun);
-    u3_noun u3yea_ecbc_en(u3_noun);
-    u3_noun u3yea_ecbc_de(u3_noun);
-
-    u3_noun u3yea_cbca_en(u3_noun);
-    u3_noun u3yea_cbca_de(u3_noun);
-    u3_noun u3yea_cbcb_en(u3_noun);
-    u3_noun u3yea_cbcb_de(u3_noun);
-    u3_noun u3yea_cbcc_en(u3_noun);
-    u3_noun u3yea_cbcc_de(u3_noun);
-
-    u3_noun u3yea_de(u3_noun);
-    u3_noun u3yea_en(u3_noun);
-
-    u3_noun u3yes_hsh(u3_noun);
-    u3_noun u3yes_hsl(u3_noun);
-    u3_noun u3yes_pbk(u3_noun);
-    u3_noun u3yes_pbl(u3_noun);
-
-    u3_noun u3ye_shax(u3_noun);
-    u3_noun u3ye_shay(u3_noun);
-    u3_noun u3ye_shas(u3_noun);
-    u3_noun u3ye_shal(u3_noun);
-
-    u3_noun u3yeo_raw(u3_noun);
-
-    u3_noun u3yee_puck(u3_noun);
-    u3_noun u3yee_sign(u3_noun);
-    u3_noun u3yee_veri(u3_noun);
-    u3_noun u3yee_shar(u3_noun);
-
-    u3_noun u3ye_bend_fun(u3_noun);
-    u3_noun u3ye_cold_fun(u3_noun);
-    u3_noun u3ye_cook_fun(u3_noun);
-    u3_noun u3ye_comp_fun(u3_noun);
-    u3_noun u3ye_easy_fun(u3_noun);
-    u3_noun u3ye_glue_fun(u3_noun);
-    u3_noun u3ye_here_fun(u3_noun);
-    u3_noun u3ye_just_fun(u3_noun);
-    u3_noun u3ye_mask_fun(u3_noun);
-    u3_noun u3ye_shim_fun(u3_noun);
-    u3_noun u3ye_stag_fun(u3_noun);
-    u3_noun u3ye_stew_fun(u3_noun);
-    u3_noun u3ye_stir_fun(u3_noun);
-
-    u3_noun u3yef_drg(u3_noun);
-    u3_noun u3yef_lug(u3_noun);
-
-    u3_noun u3yer_add(u3_noun);
-    u3_noun u3yer_sub(u3_noun);
-    u3_noun u3yer_mul(u3_noun);
-    u3_noun u3yer_div(u3_noun);
-    u3_noun u3yer_sqt(u3_noun);
-    u3_noun u3yer_fma(u3_noun);
-    u3_noun u3yer_lth(u3_noun);
-    u3_noun u3yer_lte(u3_noun);
-    u3_noun u3yer_equ(u3_noun);
-    u3_noun u3yer_gte(u3_noun);
-    u3_noun u3yer_gth(u3_noun);
-
-    u3_noun u3yet_add(u3_noun);
-    u3_noun u3yet_sub(u3_noun);
-    u3_noun u3yet_mul(u3_noun);
-    u3_noun u3yet_div(u3_noun);
-    u3_noun u3yet_sqt(u3_noun);
-    u3_noun u3yet_fma(u3_noun);
-    u3_noun u3yet_lth(u3_noun);
-    u3_noun u3yet_lte(u3_noun);
-    u3_noun u3yet_equ(u3_noun);
-    u3_noun u3yet_gte(u3_noun);
-    u3_noun u3yet_gth(u3_noun);
-
-    u3_noun u3yeq_add(u3_noun);
-    u3_noun u3yeq_sub(u3_noun);
-    u3_noun u3yeq_mul(u3_noun);
-    u3_noun u3yeq_div(u3_noun);
-    u3_noun u3yeq_sqt(u3_noun);
-    u3_noun u3yeq_fma(u3_noun);
-    u3_noun u3yeq_lth(u3_noun);
-    u3_noun u3yeq_lte(u3_noun);
-    u3_noun u3yeq_equ(u3_noun);
-    u3_noun u3yeq_gte(u3_noun);
-    u3_noun u3yeq_gth(u3_noun);
-
-    u3_noun u3yes_add(u3_noun);
-    u3_noun u3yes_sub(u3_noun);
-    u3_noun u3yes_mul(u3_noun);
-    u3_noun u3yes_div(u3_noun);
-    u3_noun u3yes_sqt(u3_noun);
-    u3_noun u3yes_fma(u3_noun);
-    u3_noun u3yes_lth(u3_noun);
-    u3_noun u3yes_lte(u3_noun);
-    u3_noun u3yes_equ(u3_noun);
-    u3_noun u3yes_gte(u3_noun);
-    u3_noun u3yes_gth(u3_noun);
-
-  /** Tier 6.
-  **/
-    u3_noun u3yf_bull(u3_noun);
-    u3_noun u3yf_cell(u3_noun);
-    u3_noun u3yf_comb(u3_noun);
-    u3_noun u3yf_cons(u3_noun);
-    u3_noun u3yf_core(u3_noun);
-    u3_noun u3yf_cube(u3_noun);
-    u3_noun u3yf_face(u3_noun);
-    u3_noun u3yf_fine(u3_noun);
-    u3_noun u3yf_fitz(u3_noun);
-    u3_noun u3yf_flan(u3_noun);
-    u3_noun u3yf_flay(u3_noun);
-    u3_noun u3yf_flip(u3_noun);
-    u3_noun u3yf_flor(u3_noun);
-    u3_noun u3yf_forq(u3_noun);
-    u3_noun u3yf_fork(u3_noun);
-    u3_noun u3yf_help(u3_noun);
-    u3_noun u3yf_hike(u3_noun);
-    u3_noun u3yf_look(u3_noun);
-    u3_noun u3yf_loot(u3_noun);
-
-    u3_noun u3yfl_bunt(u3_noun);
-    u3_noun u3yfl_whip(u3_noun);
-
-    u3_noun u3yfp_hack(u3_noun);
-    u3_noun u3yfp_late(u3_noun);
-    u3_noun u3yfp_open(u3_noun);
-    u3_noun u3yfp_rake(u3_noun);
-
-    u3_noun u3yfu_burn(u3_noun);
-    u3_noun u3yfu_busk(u3_noun);
-    u3_noun u3yfu_bust(u3_noun);
-    u3_noun u3yfu_crop(u3_noun);
-    u3_noun u3yfu_cull(u3_noun);
-    u3_noun u3yfu_duck(u3_noun);
-    u3_noun u3yfu_find(u3_noun);
-    u3_noun u3yfu_fond(u3_noun);
-    u3_noun u3yfu_fink(u3_noun);
-    u3_noun u3yfu_fire(u3_noun);
-    u3_noun u3yfu_firm(u3_noun);
-    u3_noun u3yfu_fish(u3_noun);
-    u3_noun u3yfu_fuse(u3_noun);
-    u3_noun u3yfu_heal(u3_noun);
-    u3_noun u3yfu_mint(u3_noun);
-    u3_noun u3yfu_mull(u3_noun);
-    u3_noun u3yfu_nest(u3_noun);
-    u3_noun u3yfu_peek(u3_noun);
-    u3_noun u3yfu_peel(u3_noun);
-    u3_noun u3yfu_play(u3_noun);
-    u3_noun u3yfu_repo(u3_noun);
-    u3_noun u3yfu_rest(u3_noun);
-    u3_noun u3yfu_snub(u3_noun);
-    u3_noun u3yfu_toss(u3_noun);
-    u3_noun u3yfu_wrap(u3_noun);
-
-    u3_noun u3wz_bull(u3_noun);
-    u3_noun u3wz_cell(u3_noun);
-    u3_noun u3wz_comb(u3_noun);
-    u3_noun u3wz_cons(u3_noun);
-    u3_noun u3wz_core(u3_noun);
-    u3_noun u3wz_cube(u3_noun);
-    u3_noun u3wz_face(u3_noun);
-    u3_noun u3wz_fine(u3_noun);
-    u3_noun u3wz_fitz(u3_noun);
-    u3_noun u3wz_flan(u3_noun);
-    u3_noun u3wz_flay(u3_noun);
-    u3_noun u3wz_flip(u3_noun);
-    u3_noun u3wz_flor(u3_noun);
-    u3_noun u3wz_forq(u3_noun);
-    u3_noun u3wz_fork(u3_noun);
-    u3_noun u3wz_help(u3_noun);
-    u3_noun u3wz_hike(u3_noun);
-    u3_noun u3wz_look(u3_noun);
-    u3_noun u3wz_loot(u3_noun);
-
-    u3_noun u3wzl_bunt(u3_noun);
-    u3_noun u3wzl_whip(u3_noun);
-
-    u3_noun u3wzp_hack(u3_noun);
-    u3_noun u3wzp_late(u3_noun);
-    u3_noun u3wzp_open(u3_noun);
-    u3_noun u3wzp_rake(u3_noun);
-
-    u3_noun u3wzu_burn(u3_noun);
-    u3_noun u3wzu_busk(u3_noun);
-    u3_noun u3wzu_bust(u3_noun);
-    u3_noun u3wzu_conk(u3_noun);
-    u3_noun u3wzu_crop(u3_noun);
-    u3_noun u3wzu_cull(u3_noun);
-    u3_noun u3wzu_duck(u3_noun);
-    u3_noun u3wzu_find(u3_noun);
-    u3_noun u3wzu_fond(u3_noun);
-    u3_noun u3wzu_fink(u3_noun);
-    u3_noun u3wzu_fire(u3_noun);
-    u3_noun u3wzu_firm(u3_noun);
-    u3_noun u3wzu_fish(u3_noun);
-    u3_noun u3wzu_fuse(u3_noun);
-    u3_noun u3wzu_heal(u3_noun);
-    u3_noun u3wzu_mint(u3_noun);
-    u3_noun u3wzu_mull(u3_noun);
-    u3_noun u3wzu_nest(u3_noun);
-    u3_noun u3wzu_peek(u3_noun);
-    u3_noun u3wzu_peel(u3_noun);
-    u3_noun u3wzu_play(u3_noun);
-    u3_noun u3wzu_repo(u3_noun);
-    u3_noun u3wzu_rest(u3_noun);
-    u3_noun u3wzu_snub(u3_noun);
-    u3_noun u3wzu_toss(u3_noun);
-    u3_noun u3wzu_wrap(u3_noun);
diff --git a/pkg/urbit/include/noun/aliases.h b/pkg/urbit/include/noun/aliases.h
index 5e98714d48..9304563a43 100644
--- a/pkg/urbit/include/noun/aliases.h
+++ b/pkg/urbit/include/noun/aliases.h
@@ -1,7 +1,6 @@
-/* i/n/u.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_ALIASES_H
+#define U3_ALIASES_H
+
   /**  Constants.
   **/
     /* u3_none - u3_noun which is not a noun.
@@ -112,3 +111,5 @@
 #     define  u3tn(type, x) (x == 0) ? (void *)0 :  ((type *) u3a_into(x))
 #     define  u3of(type, x) (u3a_outa((type *)x))
 
+
+#endif /* ifndef U3_ALIASES_H */
diff --git a/pkg/urbit/include/noun/allocate.h b/pkg/urbit/include/noun/allocate.h
index fa84df233a..7b9d843157 100644
--- a/pkg/urbit/include/noun/allocate.h
+++ b/pkg/urbit/include/noun/allocate.h
@@ -1,10 +1,10 @@
-/* i/n/a.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_ALLOCATE_H
+#define U3_ALLOCATE_H
 
 #include <openssl/opensslv.h>
 
+#include "manage.h"
+
   /**  Constants.
   **/
     /* u3a_bits: number of bits in word-addressed pointer.  29 == 2GB.
@@ -400,12 +400,6 @@
             return u3a_peek(pil_u);
           }
 
-        //  we have to forward-declare u3m_bail() here, as our
-        //  headers don't have the necessary guards.
-        //
-          c3_i
-          u3m_bail(c3_m how_m) __attribute__((noreturn));
-
         /* u3a_pile_sane(): bail on invalid road stack state.
         */
           inline void
@@ -721,3 +715,5 @@
         */
           c3_c*
           u3a_string(u3_atom a);
+
+#endif /* ifndef U3_ALLOCATE_H */
diff --git a/pkg/urbit/include/noun/events.h b/pkg/urbit/include/noun/events.h
index bee2d8ad57..47ee9afc38 100644
--- a/pkg/urbit/include/noun/events.h
+++ b/pkg/urbit/include/noun/events.h
@@ -1,7 +1,6 @@
-/* i/n/e.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_EVENTS_H
+#define U3_EVENTS_H
+
   /** Data structures.
   **/
     /* u3e_line: control line.
@@ -89,3 +88,5 @@
     */
       void
       u3e_foul(void);
+
+#endif /* ifndef U3_EVENTS_H */
diff --git a/pkg/urbit/include/noun/hashtable.h b/pkg/urbit/include/noun/hashtable.h
index e69a060d2c..8c69b13b95 100644
--- a/pkg/urbit/include/noun/hashtable.h
+++ b/pkg/urbit/include/noun/hashtable.h
@@ -1,7 +1,6 @@
-/* include/n/h.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_HASHTABLE_H
+#define U3_HASHTABLE_H
+
   /**  Data structures.
   **/
     /**  Straightforward implementation of the classic Bagwell
@@ -182,3 +181,5 @@
       */
         c3_w
         u3h_wyt(u3p(u3h_root) har_p);
+
+#endif /* ifndef U3_HASHTABLE_H */
diff --git a/pkg/urbit/include/noun/imprison.h b/pkg/urbit/include/noun/imprison.h
index d4d28a87e8..c68088eee4 100644
--- a/pkg/urbit/include/noun/imprison.h
+++ b/pkg/urbit/include/noun/imprison.h
@@ -1,7 +1,5 @@
-/* include/noun/imprison.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_IMPRISON_H
+#define U3_IMPRISON_H
 
   /**  Structures.
   **/
@@ -157,3 +155,5 @@
         */
           u3_noun
           u3i_molt(u3_noun som, ...);
+
+#endif /* ifndef U3_IMPRISON_H */
diff --git a/pkg/urbit/include/noun/jets.h b/pkg/urbit/include/noun/jets.h
index 6a9d277566..5b1c4f03c8 100644
--- a/pkg/urbit/include/noun/jets.h
+++ b/pkg/urbit/include/noun/jets.h
@@ -1,7 +1,6 @@
-/* include/n/j.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_JETS_H
+#define U3_JETS_H
+
   /** Noun semantics.
   **/
 #if 0
@@ -301,3 +300,5 @@
       */
         void
         u3j_rewrite_compact();
+
+#endif /* ifndef U3_JETS_H */
diff --git a/pkg/urbit/include/noun/log.h b/pkg/urbit/include/noun/log.h
index 07ab2296cb..e786eff5f8 100644
--- a/pkg/urbit/include/noun/log.h
+++ b/pkg/urbit/include/noun/log.h
@@ -1,6 +1,5 @@
-/* noun/log.h
-**
-*/
+#ifndef U3_LOG_H
+#define U3_LOG_H
 
 /* u3l_log(): logs to stderr or redirects to configured function.
 */
@@ -17,3 +16,5 @@
  */
   u3_weak
   u3l_punt(const char* name, u3_weak pro);
+
+#endif /* ifndef U3_LOG_H */
diff --git a/pkg/urbit/include/noun/manage.h b/pkg/urbit/include/noun/manage.h
index 4f676e6655..5c522bcd17 100644
--- a/pkg/urbit/include/noun/manage.h
+++ b/pkg/urbit/include/noun/manage.h
@@ -1,7 +1,6 @@
-/* i/n/m.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_MANAGE_H
+#define U3_MANAGE_H
+
     /** System management.
     **/
       /* u3m_boot(): start the u3 system. return next event, starting from 1.
@@ -149,3 +148,5 @@
       */
         c3_w
         u3m_pack(void);
+
+#endif /* ifndef U3_MANAGE_H */
diff --git a/pkg/urbit/include/noun/nock.h b/pkg/urbit/include/noun/nock.h
index 1e7c6430ea..561cb7585f 100644
--- a/pkg/urbit/include/noun/nock.h
+++ b/pkg/urbit/include/noun/nock.h
@@ -1,7 +1,6 @@
-/* i/n/n.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_NOCK_H
+#define U3_NOCK_H
+
   /** Data structures.
   ***
   **/
@@ -136,3 +135,5 @@
     */
       void
       u3n_ream(void);
+
+#endif /* ifndef U3_NOCK_H */
diff --git a/pkg/urbit/include/noun/options.h b/pkg/urbit/include/noun/options.h
index 5aecc17580..f73dba264d 100644
--- a/pkg/urbit/include/noun/options.h
+++ b/pkg/urbit/include/noun/options.h
@@ -1,7 +1,6 @@
-/* i/n/o.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_OPTIONS_H
+#define U3_OPTIONS_H
+
   /** Data structures.
   **/
     /* u3o_config: process / system configuration.
@@ -40,3 +39,5 @@
       c3_global u3o_config u3o_Config;
 #     define u3C u3o_Config
 
+
+#endif /* ifndef U3_OPTIONS_H */
diff --git a/pkg/urbit/include/noun/retrieve.h b/pkg/urbit/include/noun/retrieve.h
index f5e047ee6d..edd2275bfa 100644
--- a/pkg/urbit/include/noun/retrieve.h
+++ b/pkg/urbit/include/noun/retrieve.h
@@ -1,7 +1,6 @@
-/* i/n/r.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_RETRIEVE_H
+#define U3_RETRIEVE_H
+
     /** u3r_*: read without ever crashing.
     **/
 #if 1
@@ -462,3 +461,5 @@
       */
         c3_y*
         u3r_tape(u3_noun a);
+
+#endif /* ifndef U3_RETRIEVE_H */
diff --git a/pkg/urbit/include/noun/serial.h b/pkg/urbit/include/noun/serial.h
index dca9e0ac77..89a835b992 100644
--- a/pkg/urbit/include/noun/serial.h
+++ b/pkg/urbit/include/noun/serial.h
@@ -1,6 +1,6 @@
-/* i/n/serial.h
-**
-*/
+#ifndef U3_SERIAL_H
+#define U3_SERIAL_H
+
     /*  opaque handles
     */
       /* u3_cue_xeno: handle for cue-ing with an off-loom dictionary.
@@ -75,3 +75,5 @@
       */
         u3_weak
         u3s_sift_ud(u3_atom a);
+
+#endif /* ifndef U3_SERIAL_H */
diff --git a/pkg/urbit/include/noun/trace.h b/pkg/urbit/include/noun/trace.h
index 28b42151d7..663a7eeaae 100644
--- a/pkg/urbit/include/noun/trace.h
+++ b/pkg/urbit/include/noun/trace.h
@@ -1,7 +1,6 @@
-/* i/n/t.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_TRACE_H
+#define U3_TRACE_H
+
   /** Data structures.
   **/
     /* u3t_trace: fast execution flags.
@@ -138,3 +137,5 @@
       c3_global u3t_trace u3t_Trace;
 #     define u3T u3t_Trace
 
+
+#endif /* ifndef U3_TRACE_H */
diff --git a/pkg/urbit/include/noun/urth.h b/pkg/urbit/include/noun/urth.h
index d837a72291..3fe29792e5 100644
--- a/pkg/urbit/include/noun/urth.h
+++ b/pkg/urbit/include/noun/urth.h
@@ -1,5 +1,6 @@
-/* include/noun/urth.h
-*/
+#ifndef U3_URTH_H
+#define U3_URTH_H
+
     /**  Functions.
     **/
       /* u3u_meld(): globally deduplicate memory.
@@ -35,3 +36,5 @@
       */
         c3_o
         u3u_munmap(c3_d len_d, c3_y* byt_y);
+
+#endif /* ifndef U3_URTH_H */
diff --git a/pkg/urbit/include/noun/vortex.h b/pkg/urbit/include/noun/vortex.h
index d5e261d787..90c1774d22 100644
--- a/pkg/urbit/include/noun/vortex.h
+++ b/pkg/urbit/include/noun/vortex.h
@@ -1,7 +1,6 @@
-/* include/g/v.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_VORTEX_H
+#define U3_VORTEX_H
+
   /**  Data structures.
   **/
     /* u3v_arvo: modern arvo structure.
@@ -112,3 +111,5 @@
     */
       void
       u3v_rewrite_compact();
+
+#endif /* ifndef U3_VORTEX_H */
diff --git a/pkg/urbit/include/noun/xtract.h b/pkg/urbit/include/noun/xtract.h
index 5e22a90bb6..3c26e5e4ca 100644
--- a/pkg/urbit/include/noun/xtract.h
+++ b/pkg/urbit/include/noun/xtract.h
@@ -1,7 +1,6 @@
-/* i/n/x.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_XTRACT_H
+#define U3_XTRACT_H
+
   /**  Constants.
   **/
     /* Conventional axes for gate call.
@@ -157,3 +156,5 @@
                    u3_noun* e,
                    u3_noun* f,
                    u3_noun* g);
+
+#endif /* ifndef U3_XTRACT_H */
diff --git a/pkg/urbit/include/noun/zave.h b/pkg/urbit/include/noun/zave.h
index dd48befba4..2f637c0eae 100644
--- a/pkg/urbit/include/noun/zave.h
+++ b/pkg/urbit/include/noun/zave.h
@@ -1,7 +1,6 @@
-/* i/n/z.h
-**
-** This file is in the public domain.
-*/
+#ifndef U3_ZAVE_H
+#define U3_ZAVE_H
+
   /**  Memoization.
   ***
   ***  The memo cache is keyed by an arbitrary symbolic function
@@ -37,3 +36,5 @@
     */
       u3_noun
       u3z_uniq(u3_noun som);
+
+#endif /* ifndef U3_ZAVE_H */
diff --git a/pkg/urbit/include/ur/defs.h b/pkg/urbit/include/ur/defs.h
index c16a7e153e..f6c0b00cd5 100644
--- a/pkg/urbit/include/ur/defs.h
+++ b/pkg/urbit/include/ur/defs.h
@@ -81,4 +81,4 @@ ur_met0_bytes_unsafe(uint64_t len, uint8_t *byt)
 #define ur_met3_32(a)  ur_bloq_up3(ur_met0_32(a))
 #define ur_met3_64(a)  ur_bloq_up3(ur_met0_64(a))
 
-#endif
+#endif /* ifndef UR_DEFS_H */
diff --git a/pkg/urbit/include/ur/hashcons.h b/pkg/urbit/include/ur/hashcons.h
index 01e295ddf0..f1d5b075f1 100644
--- a/pkg/urbit/include/ur/hashcons.h
+++ b/pkg/urbit/include/ur/hashcons.h
@@ -254,4 +254,4 @@ ur_walk_fore_with(ur_walk_fore_t *w,
 void
 ur_walk_fore_done(ur_walk_fore_t *w);
 
-#endif
+#endif /* ifndef UR_HASHCONS_H */
diff --git a/pkg/urbit/include/ur/serial.h b/pkg/urbit/include/ur/serial.h
index e1cf9e39f4..6010df6b68 100644
--- a/pkg/urbit/include/ur/serial.h
+++ b/pkg/urbit/include/ur/serial.h
@@ -108,4 +108,4 @@ ur_cue_test_with(ur_cue_test_t   *t,
 void
 ur_cue_test_done(ur_cue_test_t *t);
 
-#endif
+#endif /* ifndef UR_SERIAL_H */
diff --git a/pkg/urbit/include/ur/ur.h b/pkg/urbit/include/ur/ur.h
index 5b1bb222eb..5665a3cc42 100644
--- a/pkg/urbit/include/ur/ur.h
+++ b/pkg/urbit/include/ur/ur.h
@@ -1,9 +1,9 @@
-#ifndef UR_UR_H
-#define UR_UR_H
+#ifndef UR_H
+#define UR_H
 
 #include "ur/defs.h"
 #include "ur/bitstream.h"
 #include "ur/hashcons.h"
 #include "ur/serial.h"
 
-#endif
+#endif /* ifndef UR_H */
diff --git a/pkg/urbit/include/vere/db/lmdb.h b/pkg/urbit/include/vere/db/lmdb.h
index 7476b12bea..573a68fa44 100644
--- a/pkg/urbit/include/vere/db/lmdb.h
+++ b/pkg/urbit/include/vere/db/lmdb.h
@@ -1,5 +1,5 @@
-/* include/vere/db/lmdb-impl.h
-*/
+#ifndef U3_VERE_DB_LMDB_H
+#define U3_VERE_DB_LMDB_H
 
 #include <lmdb.h>
 
@@ -60,3 +60,5 @@
                         const c3_c* key_c,
                         size_t      val_i,
                         void*       val_p);
+
+#endif /* ifndef U3_VERE_DB_LMDB_H */
diff --git a/pkg/urbit/include/vere/serf.h b/pkg/urbit/include/vere/serf.h
index 4ed63f5ea0..5808f362e7 100644
--- a/pkg/urbit/include/vere/serf.h
+++ b/pkg/urbit/include/vere/serf.h
@@ -1,5 +1,5 @@
-/* include/vere/serf.h
-*/
+#ifndef U3_VERE_SERF_H
+#define U3_VERE_SERF_H
 
   /** Data types.
   **/
@@ -59,3 +59,5 @@
     */
       void
       u3_serf_grab(void);
+
+#endif /* ifndef U3_VERE_SERF_H */
diff --git a/pkg/urbit/include/vere/vere.h b/pkg/urbit/include/vere/vere.h
index a0cab581ce..64eea8eacc 100644
--- a/pkg/urbit/include/vere/vere.h
+++ b/pkg/urbit/include/vere/vere.h
@@ -1,5 +1,5 @@
-/* include/vere/vere.h
-*/
+#ifndef U3_VERE_H
+#define U3_VERE_H
 
 #include <uv.h>
 
@@ -1411,3 +1411,5 @@
 
         c3_w
         u3_readdir_r(DIR *dirp, struct dirent *entry, struct dirent **result);
+
+#endif /* ifndef U3_VERE_H */