diff --git a/lib/lua/runtime.sx b/lib/lua/runtime.sx
index 3089a8be..ecf8bac5 100644
--- a/lib/lua/runtime.sx
+++ b/lib/lua/runtime.sx
@@ -1292,6 +1292,7 @@
 (dict-set! string "gmatch" lua-string-gmatch)
 (dict-set! string "gsub" lua-string-gsub)
 (dict-set! string "format" lua-string-format)
+(dict-set! string "dump" (fn (&rest args) (str (first args))))
 (define
   lua-string-reverse
   (fn (s)
diff --git a/lib/lua/scoreboard.json b/lib/lua/scoreboard.json
index 7a854ad1..cfaf345a 100644
--- a/lib/lua/scoreboard.json
+++ b/lib/lua/scoreboard.json
@@ -1,8 +1,8 @@
 {
   "totals": {
     "pass": 1,
-    "fail": 12,
-    "timeout": 3,
+    "fail": 11,
+    "timeout": 4,
     "skip": 8,
     "total": 24,
     "runnable": 16,
@@ -11,11 +11,11 @@
   "top_failure_modes": [
     [
       "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      7
+      6
     ],
     [
       "timeout",
-      3
+      4
     ],
     [
       "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"lua: attempt to call non-functio",
@@ -51,7 +51,7 @@
       "name": "attrib.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"lua: module 'C' not found\\\\\\\"\\",
-      "ms": 6723
+      "ms": 6537
     },
     {
       "name": "big.lua",
@@ -63,7 +63,7 @@
       "name": "calls.lua",
       "status": "fail",
       "reason": "undefined symbol: fat\\",
-      "ms": 5181
+      "ms": 4965
     },
     {
       "name": "checktable.lua",
@@ -75,7 +75,7 @@
       "name": "closure.lua",
       "status": "timeout",
       "reason": "per-test timeout",
-      "ms": 8004
+      "ms": 8003
     },
     {
       "name": "code.lua",
@@ -87,7 +87,7 @@
       "name": "constructs.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"lua: attempt to compare incompat",
-      "ms": 7350
+      "ms": 7725
     },
     {
       "name": "db.lua",
@@ -99,13 +99,13 @@
       "name": "errors.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 3439
+      "ms": 4342
     },
     {
       "name": "events.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 7915
+      "ms": 7779
     },
     {
       "name": "files.lua",
@@ -123,13 +123,13 @@
       "name": "literals.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 2141
+      "ms": 1857
     },
     {
       "name": "locals.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"lua: attempt to call non-functio",
-      "ms": 1799
+      "ms": 1856
     },
     {
       "name": "main.lua",
@@ -141,43 +141,43 @@
       "name": "math.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"lua: attempt to call non-functio",
-      "ms": 4738
+      "ms": 5615
     },
     {
       "name": "nextvar.lua",
-      "status": "fail",
-      "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 7818
-    },
-    {
-      "name": "pm.lua",
-      "status": "fail",
-      "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 6478
-    },
-    {
-      "name": "sort.lua",
       "status": "timeout",
       "reason": "per-test timeout",
       "ms": 8007
     },
+    {
+      "name": "pm.lua",
+      "status": "fail",
+      "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
+      "ms": 6139
+    },
+    {
+      "name": "sort.lua",
+      "status": "timeout",
+      "reason": "per-test timeout",
+      "ms": 8003
+    },
     {
       "name": "strings.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 4339
+      "ms": 4505
     },
     {
       "name": "vararg.lua",
       "status": "fail",
       "reason": "other: Unhandled exception: \\\"Unhandled exception: \\\\\\\"assertion failed!\\\\\\\"\\",
-      "ms": 2343
+      "ms": 3031
     },
     {
       "name": "verybig.lua",
       "status": "pass",
       "reason": "",
-      "ms": 1064
+      "ms": 1213
     }
   ]
 }
\ No newline at end of file
diff --git a/lib/lua/scoreboard.md b/lib/lua/scoreboard.md
index 979c973e..da53eb8f 100644
--- a/lib/lua/scoreboard.md
+++ b/lib/lua/scoreboard.md
@@ -1,12 +1,12 @@
 # Lua-on-SX conformance scoreboard
 
 **Pass rate:** 1/16 runnable (6.2%)
-fail=12 timeout=3 skip=8 total=24
+fail=11 timeout=4 skip=8 total=24
 
 ## Top failure modes
 
-- **7x** other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\
-- **3x** timeout
+- **6x** other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\
+- **4x** timeout
 - **2x** other: Unhandled exception: \"Unhandled exception: \\\"lua: attempt to call non-functio
 - **1x** other: Unhandled exception: \"Unhandled exception: \\\"lua: module 'C' not found\\\"\
 - **1x** undefined symbol: fat\
@@ -18,25 +18,25 @@ fail=12 timeout=3 skip=8 total=24
 |---|---|---|---:|
 | all.lua | skip | driver uses dofile to chain other tests | 0 |
 | api.lua | skip | requires testC (C debug library) | 0 |
-| attrib.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"lua: module 'C' not found\\\"\ | 6723 |
+| attrib.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"lua: module 'C' not found\\\"\ | 6537 |
 | big.lua | timeout | per-test timeout | 8008 |
-| calls.lua | fail | undefined symbol: fat\ | 5181 |
+| calls.lua | fail | undefined symbol: fat\ | 4965 |
 | checktable.lua | skip | internal debug helpers | 0 |
-| closure.lua | timeout | per-test timeout | 8004 |
+| closure.lua | timeout | per-test timeout | 8003 |
 | code.lua | skip | bytecode inspection via debug library | 0 |
-| constructs.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"lua: attempt to compare incompat | 7350 |
+| constructs.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"lua: attempt to compare incompat | 7725 |
 | db.lua | skip | debug library | 0 |
-| errors.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 3439 |
-| events.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 7915 |
+| errors.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 4342 |
+| events.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 7779 |
 | files.lua | skip | io library | 0 |
 | gc.lua | skip | collectgarbage / finalisers | 0 |
-| literals.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 2141 |
-| locals.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"lua: attempt to call non-functio | 1799 |
+| literals.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 1857 |
+| locals.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"lua: attempt to call non-functio | 1856 |
 | main.lua | skip | standalone interpreter driver | 0 |
-| math.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"lua: attempt to call non-functio | 4738 |
-| nextvar.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 7818 |
-| pm.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 6478 |
-| sort.lua | timeout | per-test timeout | 8007 |
-| strings.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 4339 |
-| vararg.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 2343 |
-| verybig.lua | pass | - | 1064 |
+| math.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"lua: attempt to call non-functio | 5615 |
+| nextvar.lua | timeout | per-test timeout | 8007 |
+| pm.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 6139 |
+| sort.lua | timeout | per-test timeout | 8003 |
+| strings.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 4505 |
+| vararg.lua | fail | other: Unhandled exception: \"Unhandled exception: \\\"assertion failed!\\\"\ | 3031 |
+| verybig.lua | pass | - | 1213 |
diff --git a/plans/lua-on-sx.md b/plans/lua-on-sx.md
index 8637c26e..b0b6ea53 100644
--- a/plans/lua-on-sx.md
+++ b/plans/lua-on-sx.md
@@ -82,6 +82,7 @@ Each item: implement → tests → tick box → update progress log.
 
 _Newest first. Agent appends on every commit._
 
+- 2026-04-25: lua: scoreboard iteration — `string.dump` stub (returns string-of-fn). Diagnosed calls.lua: file ENDS with `return deep` (line 295), which makes my `lua-has-top-return?` correctly return true, triggering the guard, which scopes user defines and breaks loadstring's lexical capture of `fat`. The fix would require either rewriting top-level returns into a different mechanism (post-processing the AST) or implementing a real `_G` global table for global assignment/lookup. Both larger.
 - 2026-04-25: lua: scoreboard iteration — `math.mod` (Lua 5.0 alias for `fmod`), `math.frexp` (mantissa/exponent split), `math.ldexp` (m·2^e). math.lua moves past line-103 `math.mod` call. Timeouts 6→3, asserts 5→7. 393/393 green.
 - 2026-04-25: lua: scoreboard iteration — `unpack(t, i, j)` now treats explicit nil for `i` or `j` as missing (defaults to 1 and `#t`). vararg.lua-style `unpack(args, 1, args.n)` works when `args.n` is nil. Asserts 4→5, timeouts 8→6 (more tests reach assertions instead of timing out). 393/393 green.
 - 2026-04-25: lua: scoreboard iteration — extended `string.format`. New `%x`/`%X`/`%o` (hex/octal), `%c` (codepoint→char via `lua-char-one`), `%q` (basic quote), width N (`%5d`), zero-pad (`%05d`), left-align (`%-5d`), `%.Ns` precision. Helpers `lua-fmt-pad` and `lua-fmt-int-base`. 393/393 green (+6 format tests).