Stage D batch 4: mama_forth_words.c groups 1+2 -- capsule/lifecycle words + BIRTH/START/KILL (FABRIC-3.md §XXXII.6)

15 of mama_forth_words.c's 48 silent sites fixed, split by functional
grouping per direct instruction: CAPSULE@/CAPSULE-HASH@/CAPSULE-FLAGS@/
CAPSULE-LEN@/CAPSULE-BIRTH/CAPSULE-RUN/EXEC (9), and BIRTH/START/KILL
(6).

Refined the diagnostic-placement rule: match whichever convention that
same function's other already-correct guards use, rather than
defaulting uniformly. BIRTH/START/KILL/EXEC each already had a
console_println() sibling guard ("name too long or empty") -- their
newly-diagnosed guards now match that, same shape as USE's own fix.
The CAPSULE*@ words have no sibling guard to match, so they keep
log_message() (defer_words.c's gold-standard default).

Three-arch clean qemu acceptance passed; BIRTH itself is exercised by
every boot (Hermes/Artemis birth).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BWpNjdwPtFLuVLaAq44L9K

FABRIC-3.md

@@ -4605,3 +4605,32 @@ regression unaffected -- including the full POST word-test suite, which exercise
 `vm_compile_word`/`vm_compile_call`/`execute_colon_word` extensively via every colon-definition
 test case, with zero regressions from either the diagnostics or the two NULL-guard fixes.
 
+**`mama_forth_words.c` (48 sites) -- per direct instruction, split by functional grouping
+rather than mechanical file-order chunks or one single batch. Six groups identified from
+§XXXII.3's own per-file site list:** capsule descriptor/lifecycle words + `EXEC` (9: `CAPSULE@`/
+`CAPSULE-HASH@`/`CAPSULE-FLAGS@`/`CAPSULE-LEN@`/`CAPSULE-BIRTH`/`CAPSULE-RUN`/`EXEC`); VM
+lifecycle words (6: `BIRTH`/`START`/`KILL`); cross-VM execution/dispatch (11: `VM-STEP`/
+`VM-EXEC`/`VM-CALL`/`SWITCH-MARK-WORK`/`VM-HEAT`); identity/crypto (10: `MINT` + its
+`mint_pop_string()` helper/`ZUSE-ELIGIBILITY-ADD`/`ZUSE-ELIGIBLE?`/`ELEVATE-PUBKEY-UNPACK`);
+dictionary lookup + diagnostic/test words (6: `NAME>XT`/`RUNCAP-TEST`/`PAIR-TEST`); Stadium/
+physics primitives (6: `STADIUM-ADMIT`/`STADIUM-EVICT`/`STADIUM-RES-PULL`/`STADIUM-RES-PUSH`/
+`STADIUM-HEAT@`/`STADIUM-HEAT!`). Groups combined two-at-a-time per commit for acceptance-boot
+economy (each full rebuild+3-arch cycle costs the same regardless of diff size within one file),
+documented separately below per group.
+
+**Batch 4 -- DONE, 2026-09-15: groups 1+2 (capsule descriptor/lifecycle words + EXEC, and VM
+lifecycle words BIRTH/START/KILL) -- 15 sites.** Refined the diagnostic-placement rule while
+doing this batch: rather than defaulting to `log_message()` everywhere (batches 1-3's own
+default, absent any sibling to match), **match whichever convention that same function's other
+already-correct guards already use.** `BIRTH`/`START`/`KILL`/`EXEC` each already had a sibling
+guard using `console_println()` ("name too long or empty") -- their newly-diagnosed guards now
+use `console_println()` too, for internal consistency within the same function, matching `USE`'s
+own five-guard precedent exactly (these are all `S" name"`-taking, directly-interactive commands,
+the same shape `USE` is). The four `CAPSULE*@` fetch words and `CAPSULE-BIRTH`/`CAPSULE-RUN` have
+no such sibling (a single guard each) -- kept `log_message()`, matching `defer_words.c`'s
+gold-standard default for a function with nothing else to match against.
+
+**Verified:** three-architecture `clean qemu` acceptance (amd64/aarch64/riscv64) passed --
+`BIRTH` itself is exercised heavily by every boot (Hermes/Artemis birth), a real regression check
+beyond compile-cleanliness for this specific batch.
+

capsules/BLOCK_MAP.md

@@ -1,5 +1,5 @@
 # Capsule Block Manifest — Auto-generated
-<!-- Generated by mkcapsule --manifest  2026-09-15T21:25:23Z -->
+<!-- Generated by mkcapsule --manifest  2026-09-15T22:41:56Z -->
 <!-- DO NOT EDIT — re-run mkcapsule --manifest to refresh.  -->
 <!-- Hand-written justifications and immutability notes live  -->
 <!-- in MANIFEST.md alongside this auto-generated index.      -->

src/starkernel/capsule/mama_forth_words.c

@@ -93,6 +93,7 @@ void mama_word_capsule_count(VM *vm)
 void mama_word_capsule_fetch(VM *vm)
 {
     if (vm->dsp < 0) {
+        log_message(LOG_ERROR, "CAPSULE@: stack underflow");
         vm->error = 1;
         return;
     }
@@ -115,6 +116,7 @@ void mama_word_capsule_fetch(VM *vm)
 void mama_word_capsule_hash_fetch(VM *vm)
 {
     if (vm->dsp < 0) {
+        log_message(LOG_ERROR, "CAPSULE-HASH@: stack underflow");
         vm->error = 1;
         return;
     }
@@ -137,6 +139,7 @@ void mama_word_capsule_hash_fetch(VM *vm)
 void mama_word_capsule_flags_fetch(VM *vm)
 {
     if (vm->dsp < 0) {
+        log_message(LOG_ERROR, "CAPSULE-FLAGS@: stack underflow");
         vm->error = 1;
         return;
     }
@@ -159,6 +162,7 @@ void mama_word_capsule_flags_fetch(VM *vm)
 void mama_word_capsule_len_fetch(VM *vm)
 {
     if (vm->dsp < 0) {
+        log_message(LOG_ERROR, "CAPSULE-LEN@: stack underflow");
         vm->error = 1;
         return;
     }
@@ -240,6 +244,7 @@ void mama_word_birth(VM *vm)
     VMUuid          new_vm_id;
 
     if (vm->dsp < 1) {
+        console_println("BIRTH: expects S\" name\" BIRTH -- nothing on the stack");
         vm->error = 1;
         return;
     }
@@ -255,7 +260,11 @@ void mama_word_birth(VM *vm)
     /* caddr is a VM address; S" ( -- c-addr u ) stores chars directly at caddr */
     {
         const uint8_t *p = vm_ptr(vm, (vaddr_t)caddr);
-        if (!p) { vm->error = 1; return; }
+        if (!p) {
+            console_println("BIRTH: invalid address on the stack");
+            vm->error = 1;
+            return;
+        }
         src = (const char *)p;
     }
     for (i = 0; i < (uint32_t)u; i++) name_buf[i] = src[i];
@@ -347,6 +356,7 @@ void mama_word_start(VM *vm)
     VM              *target;
 
     if (vm->dsp < 1) {
+        console_println("START: expects S\" name\" START -- nothing on the stack");
         vm->error = 1;
         return;
     }
@@ -362,7 +372,11 @@ void mama_word_start(VM *vm)
     /* caddr is a VM address; S" ( -- c-addr u ) stores chars directly at caddr */
     {
         const uint8_t *p = vm_ptr(vm, (vaddr_t)caddr);
-        if (!p) { vm->error = 1; return; }
+        if (!p) {
+            console_println("START: invalid address on the stack");
+            vm->error = 1;
+            return;
+        }
         src = (const char *)p;
     }
     for (i = 0; i < (uint32_t)u; i++) name_buf[i] = src[i];
@@ -558,6 +572,7 @@ void mama_word_kill(VM *vm)
     const char *src;
 
     if (vm->dsp < 1) {
+        console_println("KILL: expects S\" name\" KILL -- nothing on the stack");
         vm->error = 1;
         return;
     }
@@ -573,7 +588,11 @@ void mama_word_kill(VM *vm)
     /* caddr is a VM address; S" ( -- c-addr u ) stores chars directly at caddr */
     {
         const uint8_t *p = vm_ptr(vm, (vaddr_t)caddr);
-        if (!p) { vm->error = 1; return; }
+        if (!p) {
+            console_println("KILL: invalid address on the stack");
+            vm->error = 1;
+            return;
+        }
         src = (const char *)p;
     }
     for (i = 0; i < (uint32_t)u; i++) name_buf[i] = src[i];
@@ -1319,6 +1338,7 @@ static void mama_word_pair_test(VM *vm)
 void mama_word_capsule_birth(VM *vm)
 {
     if (vm->dsp < 0) {
+        log_message(LOG_ERROR, "CAPSULE-BIRTH: stack underflow");
         vm->error = 1;
         return;
     }
@@ -1359,6 +1379,7 @@ void mama_word_capsule_birth(VM *vm)
 void mama_word_capsule_run(VM *vm)
 {
     if (vm->dsp < 0) {
+        log_message(LOG_ERROR, "CAPSULE-RUN: stack underflow");
         vm->error = 1;
         return;
     }
@@ -1366,6 +1387,8 @@ void mama_word_capsule_run(VM *vm)
     cell_t capsule_idx = vm_pop(vm);
 
     if ((uint64_t)capsule_idx >= capsule_get_desc_count()) {
+        log_message(LOG_ERROR, "CAPSULE-RUN: capsule index %lld out of range",
+                    (long long)capsule_idx);
         vm->error = 1;
         return;
     }
@@ -1464,7 +1487,11 @@ void mama_word_exec(VM *vm)
     int          saved_dsp;
     int          saved_rsp;
 
-    if (vm->dsp < 1) { vm->error = 1; return; }
+    if (vm->dsp < 1) {
+        console_println("EXEC: expects S\" name\" EXEC -- nothing on the stack");
+        vm->error = 1;
+        return;
+    }
 
     u     = vm_pop(vm);
     caddr = vm_pop(vm);
@@ -1476,7 +1503,11 @@ void mama_word_exec(VM *vm)
 
     {
         const uint8_t *p = vm_ptr(vm, (vaddr_t)caddr);
-        if (!p) { vm->error = 1; return; }
+        if (!p) {
+            console_println("EXEC: invalid address on the stack");
+            vm->error = 1;
+            return;
+        }
         src = (const char *)p;
     }
     for (i = 0; i < (uint32_t)u; i++) name_buf[i] = src[i];