diff --git a/lib/mod/conformance.conf b/lib/mod/conformance.conf
index 9f348d59..e558811f 100644
--- a/lib/mod/conformance.conf
+++ b/lib/mod/conformance.conf
@@ -21,6 +21,7 @@ PRELOADS=(
   lib/mod/whatif.sx
   lib/mod/batch.sx
   lib/mod/temporal.sx
+  lib/mod/sla.sx
   lib/mod/lifecycle.sx
   lib/mod/audit.sx
   lib/mod/api.sx
@@ -44,4 +45,5 @@ SUITES=(
   "whatif:lib/mod/tests/whatif.sx:(mod-whatif-tests-run!)"
   "batch:lib/mod/tests/batch.sx:(mod-batch-tests-run!)"
   "temporal:lib/mod/tests/temporal.sx:(mod-temporal-tests-run!)"
+  "sla:lib/mod/tests/sla.sx:(mod-sla-tests-run!)"
 )
diff --git a/lib/mod/scoreboard.json b/lib/mod/scoreboard.json
index 40cf2c07..97f2beb8 100644
--- a/lib/mod/scoreboard.json
+++ b/lib/mod/scoreboard.json
@@ -1,8 +1,8 @@
 {
   "lang": "mod",
-  "total_passed": 292,
+  "total_passed": 307,
   "total_failed": 0,
-  "total": 292,
+  "total": 307,
   "suites": [
     {"name":"decide","passed":31,"failed":0,"total":31},
     {"name":"audit","passed":29,"failed":0,"total":29},
@@ -17,7 +17,8 @@
     {"name":"trace","passed":15,"failed":0,"total":15},
     {"name":"whatif","passed":13,"failed":0,"total":13},
     {"name":"batch","passed":17,"failed":0,"total":17},
-    {"name":"temporal","passed":15,"failed":0,"total":15}
+    {"name":"temporal","passed":15,"failed":0,"total":15},
+    {"name":"sla","passed":15,"failed":0,"total":15}
   ],
-  "generated": "2026-06-06T19:00:19+00:00"
+  "generated": "2026-06-06T19:08:06+00:00"
 }
diff --git a/lib/mod/scoreboard.md b/lib/mod/scoreboard.md
index f66956bc..680ef546 100644
--- a/lib/mod/scoreboard.md
+++ b/lib/mod/scoreboard.md
@@ -1,6 +1,6 @@
 # mod scoreboard
 
-**292 / 292 passing** (0 failure(s)).
+**307 / 307 passing** (0 failure(s)).
 
 | Suite | Passed | Total | Status |
 |-------|--------|-------|--------|
@@ -18,3 +18,4 @@
 | whatif | 13 | 13 | ok |
 | batch | 17 | 17 | ok |
 | temporal | 15 | 15 | ok |
+| sla | 15 | 15 | ok |
diff --git a/lib/mod/sla.sx b/lib/mod/sla.sx
new file mode 100644
index 00000000..4a437957
--- /dev/null
+++ b/lib/mod/sla.sx
@@ -0,0 +1,47 @@
+;; lib/mod/sla.sx — service-level sweep over pending lifecycle cases.
+;;
+;; Composes the Phase-3 lifecycle with the Ext-12 time dimension: a case left in a
+;; pending state (open / triaged / appealed) past a deadline has breached SLA and
+;; should resurface. A timed-case pairs a case with the tick it entered its
+;; current state (the caller stamps this — the lifecycle stays timeless and pure).
+;; Terminal states (decided / final) never breach.
+
+(define mod/pending-states (list "open" "triaged" "appealed"))
+(define mod/pending-state? (fn (s) (mod/member? s mod/pending-states)))
+
+(define mod/mk-timed-case (fn (c entered-at) {:entered-at entered-at :case c}))
+(define mod/tc-case (fn (tc) (get tc :case)))
+(define mod/tc-entered-at (fn (tc) (get tc :entered-at)))
+
+(define
+  mod/overdue?
+  (fn
+    (tc now deadline)
+    (if
+      (mod/pending-state? (mod/case-state (mod/tc-case tc)))
+      (< deadline (- now (mod/tc-entered-at tc)))
+      false)))
+
+(define
+  mod/sla-sweep
+  (fn
+    (timed-cases now deadline)
+    (reduce
+      (fn
+        (acc tc)
+        (if
+          (mod/overdue? tc now deadline)
+          (append
+            acc
+            (list (mod/report-id (mod/case-report (mod/tc-case tc)))))
+          acc))
+      (list)
+      timed-cases)))
+
+(define
+  mod/overdue-count
+  (fn
+    (timed-cases now deadline)
+    (len (mod/sla-sweep timed-cases now deadline))))
+
+(define mod/age (fn (tc now) (- now (mod/tc-entered-at tc))))
diff --git a/lib/mod/tests/sla.sx b/lib/mod/tests/sla.sx
new file mode 100644
index 00000000..ccf50ec9
--- /dev/null
+++ b/lib/mod/tests/sla.sx
@@ -0,0 +1,108 @@
+;; lib/mod/tests/sla.sx — Ext 13: SLA sweep over pending lifecycle cases.
+
+(define mod-sla-count 0)
+(define mod-sla-pass 0)
+(define mod-sla-fail 0)
+(define mod-sla-failures (list))
+
+(define
+  mod-sla-test!
+  (fn
+    (name got expected)
+    (begin
+      (set! mod-sla-count (+ mod-sla-count 1))
+      (if
+        (= got expected)
+        (set! mod-sla-pass (+ mod-sla-pass 1))
+        (begin
+          (set! mod-sla-fail (+ mod-sla-fail 1))
+          (append!
+            mod-sla-failures
+            (str name "\n    expected: " expected "\n    got:      " got)))))))
+
+;; ── pending-state? ──
+
+(mod-sla-test! "open is pending" (mod/pending-state? "open") true)
+(mod-sla-test! "triaged is pending" (mod/pending-state? "triaged") true)
+(mod-sla-test! "appealed is pending" (mod/pending-state? "appealed") true)
+(mod-sla-test! "decided is not pending" (mod/pending-state? "decided") false)
+(mod-sla-test! "final is not pending" (mod/pending-state? "final") false)
+
+;; build cases in known states
+(define mod-sla-spam (mod/mk-report "r1" "u" "bob" "this is spam"))
+(define mod-sla-spam-reports (list mod-sla-spam))
+(define
+  mod-sla-triaged
+  (mod/case-triage
+    (mod/mk-case mod-sla-spam)
+    mod-sla-spam-reports
+    mod/default-rules))
+(define mod-sla-decided (mod/case-resolve mod-sla-triaged))
+(define mod-sla-open (mod/mk-case (mod/mk-report "r2" "u" "eve" "hello")))
+
+;; ── overdue? ──
+
+(define mod-sla-tc-old (mod/mk-timed-case mod-sla-triaged 0))
+(define mod-sla-tc-fresh (mod/mk-timed-case mod-sla-triaged 90))
+(define mod-sla-tc-done (mod/mk-timed-case mod-sla-decided 0))
+
+(mod-sla-test!
+  "old triaged case is overdue"
+  (mod/overdue? mod-sla-tc-old 100 50)
+  true)
+(mod-sla-test!
+  "fresh triaged case not overdue"
+  (mod/overdue? mod-sla-tc-fresh 100 50)
+  false)
+(mod-sla-test!
+  "decided case never overdue"
+  (mod/overdue? mod-sla-tc-done 100 50)
+  false)
+(mod-sla-test!
+  "age computes elapsed ticks"
+  (mod/age mod-sla-tc-old 100)
+  100)
+(mod-sla-test!
+  "boundary: exactly at deadline not overdue"
+  (mod/overdue?
+    (mod/mk-timed-case mod-sla-triaged 50)
+    100
+    50)
+  false)
+(mod-sla-test!
+  "boundary: one past deadline overdue"
+  (mod/overdue?
+    (mod/mk-timed-case mod-sla-triaged 49)
+    100
+    50)
+  true)
+
+;; ── sweep over a mixed queue ──
+
+(define
+  mod-sla-queue
+  (list
+    (mod/mk-timed-case mod-sla-triaged 0)
+    (mod/mk-timed-case mod-sla-decided 0)
+    (mod/mk-timed-case mod-sla-open 90)))      ;; r2, pending, age 10 → not
+
+(mod-sla-test!
+  "sweep finds only the overdue pending case"
+  (mod/sla-sweep mod-sla-queue 100 50)
+  (list "r1"))
+(mod-sla-test!
+  "overdue-count agrees"
+  (mod/overdue-count mod-sla-queue 100 50)
+  1)
+
+;; tighten deadline so the young open case also breaches
+(mod-sla-test!
+  "tighter deadline catches the open case too"
+  (mod/overdue-count mod-sla-queue 100 5)
+  2)
+(mod-sla-test!
+  "empty queue → no breaches"
+  (mod/sla-sweep (list) 100 50)
+  (list))
+
+(define mod-sla-tests-run! (fn () {:failures mod-sla-failures :total mod-sla-count :passed mod-sla-pass :failed mod-sla-fail}))
diff --git a/plans/mod-on-sx.md b/plans/mod-on-sx.md
index 0d394230..742919eb 100644
--- a/plans/mod-on-sx.md
+++ b/plans/mod-on-sx.md
@@ -16,7 +16,7 @@ federation extension.
 
 ## Status (rolling)
 
-`bash lib/mod/conformance.sh` → **292/292** (roadmap + 12 extensions complete)
+`bash lib/mod/conformance.sh` → **307/307** (roadmap + 13 extensions complete)
 
 ## Ground rules
 
@@ -147,6 +147,11 @@ lib/mod/fed.sx
   derivation goal-by-goal with `[proved]`/`[unproved]` marks and unification
   bindings. E.g. `Report rc: escalate (rule: repeated-escalate)` … `[proved]
   report(rc, B, S), report_count(S, N), N >= 3  {B=ann, N=3, S=dave}`.
+- [x] **Ext 13 — SLA sweep over pending cases** (`lib/mod/sla.sx`, +15). Composes
+  lifecycle (Phase 3) with time (Ext 12): a timed-case pairs a case with the tick
+  it entered its state; `mod/overdue?` flags pending cases (open/triaged/appealed)
+  past a deadline; `mod/sla-sweep` returns the breached report ids. Terminal states
+  never breach. Pure overlay — lifecycle stays timeless, the caller stamps entry.
 - [x] **Ext 12 — temporal burst detection** (`lib/mod/temporal.sx`, +15). Reports
   gain an `:at` tick (deterministic, supplied — never clock-read).
   `mod/decide-temporal now window` counts reports about the subject within
@@ -202,6 +207,11 @@ lib/mod/fed.sx
 
 ## Progress log
 
+- **Ext 13 — SLA sweep, 307/307** (+15). Two subsystems compose cleanly: lifecycle
+  states + temporal ticks → "which pending cases have sat too long". Kept lifecycle
+  pure by having the SLA layer carry entry-time externally (timed-case wrapper)
+  rather than stamping the case — same separation-of-concerns as keeping the state
+  machine out of Prolog.
 - **Ext 12 — temporal burst detection, 292/292** (+15). Adds the time dimension:
   a windowed count distinguishes a burst from slow accumulation, where the plain
   count rule cannot. Time is a supplied tick (`:at`), keeping everything