mod: Ext 11 — batch triage + corpus analytics, 277/277

mod/decide-batch triages a queue; mod/action-histogram summarizes outcomes by
action; mod/rule-coverage + mod/never-fired measure which rules fire across a
corpus — the empirical complement to lint's static unreachable check (lint finds
rules that can't fire; never-fired finds rules that didn't). +17 tests.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/mod/batch.sx

@@ -0,0 +1,55 @@
+;; lib/mod/batch.sx — batch triage + corpus analytics.
+;;
+;; Operational layer: decide a whole queue of reports at once, summarize the
+;; outcomes by action, and measure which rules actually fire across a corpus.
+;; mod/never-fired is the empirical complement to lint's static unreachable check
+;; (Ext 5): lint finds rules that CAN'T fire by structure; never-fired finds rules
+;; that DIDN'T fire on real data.
+
+(define
+  mod/decide-batch
+  (fn
+    (reports rules)
+    (map (fn (r) (mod/decide-report r reports rules)) reports)))
+
+(define
+  mod/count-action
+  (fn
+    (decisions action)
+    (reduce
+      (fn (acc d) (if (= (get d :action) action) (+ acc 1) acc))
+      0
+      decisions)))
+
+(define mod/action-histogram (fn (decisions) {:keep (mod/count-action decisions "keep") :remove (mod/count-action decisions "remove") :escalate (mod/count-action decisions "escalate") :hide (mod/count-action decisions "hide") :ban (mod/count-action decisions "ban")}))
+
+(define
+  mod/rule-fire-count
+  (fn
+    (decisions rule-name)
+    (reduce
+      (fn (acc d) (if (= (get d :rule) rule-name) (+ acc 1) acc))
+      0
+      decisions)))
+
+(define
+  mod/rule-coverage
+  (fn
+    (reports rules)
+    (let
+      ((decisions (mod/decide-batch reports rules)))
+      (map (fn (rule) {:rule (mod/rule-name rule) :fired (mod/rule-fire-count decisions (mod/rule-name rule))}) rules))))
+
+(define
+  mod/never-fired
+  (fn
+    (reports rules)
+    (reduce
+      (fn
+        (acc c)
+        (if
+          (= (get c :fired) 0)
+          (append acc (list (get c :rule)))
+          acc))
+      (list)
+      (mod/rule-coverage reports rules))))

lib/mod/conformance.conf

@@ -19,6 +19,7 @@ PRELOADS=(
   lib/mod/quorum.sx
   lib/mod/trace.sx
   lib/mod/whatif.sx
+  lib/mod/batch.sx
   lib/mod/lifecycle.sx
   lib/mod/audit.sx
   lib/mod/api.sx
@@ -40,4 +41,5 @@ SUITES=(
   "quorum:lib/mod/tests/quorum.sx:(mod-quorum-tests-run!)"
   "trace:lib/mod/tests/trace.sx:(mod-trace-tests-run!)"
   "whatif:lib/mod/tests/whatif.sx:(mod-whatif-tests-run!)"
+  "batch:lib/mod/tests/batch.sx:(mod-batch-tests-run!)"
 )

lib/mod/scoreboard.json

@@ -1,8 +1,8 @@
 {
   "lang": "mod",
-  "total_passed": 260,
+  "total_passed": 277,
   "total_failed": 0,
-  "total": 260,
+  "total": 277,
   "suites": [
     {"name":"decide","passed":31,"failed":0,"total":31},
     {"name":"audit","passed":29,"failed":0,"total":29},
@@ -15,7 +15,8 @@
     {"name":"offenders","passed":19,"failed":0,"total":19},
     {"name":"quorum","passed":9,"failed":0,"total":9},
     {"name":"trace","passed":15,"failed":0,"total":15},
-    {"name":"whatif","passed":13,"failed":0,"total":13}
+    {"name":"whatif","passed":13,"failed":0,"total":13},
+    {"name":"batch","passed":17,"failed":0,"total":17}
   ],
-  "generated": "2026-06-06T18:51:15+00:00"
+  "generated": "2026-06-06T18:55:47+00:00"
 }

lib/mod/scoreboard.md

@@ -1,6 +1,6 @@
 # mod scoreboard
 
-**260 / 260 passing** (0 failure(s)).
+**277 / 277 passing** (0 failure(s)).
 
 | Suite | Passed | Total | Status |
 |-------|--------|-------|--------|
@@ -16,3 +16,4 @@
 | quorum | 9 | 9 | ok |
 | trace | 15 | 15 | ok |
 | whatif | 13 | 13 | ok |
+| batch | 17 | 17 | ok |

lib/mod/tests/batch.sx

@@ -0,0 +1,101 @@
+;; lib/mod/tests/batch.sx — Ext 11: batch triage + corpus analytics.
+
+(define mod-b-count 0)
+(define mod-b-pass 0)
+(define mod-b-fail 0)
+(define mod-b-failures (list))
+
+(define
+  mod-b-test!
+  (fn
+    (name got expected)
+    (begin
+      (set! mod-b-count (+ mod-b-count 1))
+      (if
+        (= got expected)
+        (set! mod-b-pass (+ mod-b-pass 1))
+        (begin
+          (set! mod-b-fail (+ mod-b-fail 1))
+          (append!
+            mod-b-failures
+            (str name "\n    expected: " expected "\n    got:      " got)))))))
+
+;; corpus: 2 spam, 1 abuse, 2 clean — distinct subjects so the count rule stays quiet
+(define
+  mod-b-corpus
+  (list
+    (mod/mk-report "r1" "u" "s1" "this is spam")
+    (mod/mk-report "r2" "u" "s2" "buy now offer")
+    (mod/mk-report "r3" "u" "s3" "harassment here")
+    (mod/mk-report "r4" "u" "s4" "a fine post")
+    (mod/mk-report "r5" "u" "s5" "thanks for sharing")))
+
+(define mod-b-decisions (mod/decide-batch mod-b-corpus mod/default-rules))
+
+;; ── decide-batch ──
+
+(mod-b-test! "one decision per report" (len mod-b-decisions) 5)
+(mod-b-test!
+  "first decision is hide"
+  (get (first mod-b-decisions) :action)
+  "hide")
+
+;; ── action histogram ──
+
+(define mod-b-hist (mod/action-histogram mod-b-decisions))
+(mod-b-test! "histogram hide count" (get mod-b-hist :hide) 2)
+(mod-b-test! "histogram remove count" (get mod-b-hist :remove) 1)
+(mod-b-test! "histogram keep count" (get mod-b-hist :keep) 2)
+(mod-b-test! "histogram escalate count" (get mod-b-hist :escalate) 0)
+(mod-b-test! "histogram ban count" (get mod-b-hist :ban) 0)
+(mod-b-test!
+  "histogram totals match corpus"
+  (+
+    (+ (get mod-b-hist :hide) (get mod-b-hist :remove))
+    (+
+      (get mod-b-hist :keep)
+      (+ (get mod-b-hist :escalate) (get mod-b-hist :ban))))
+  5)
+
+;; ── rule coverage (empirical) ──
+
+(define mod-b-cov (mod/rule-coverage mod-b-corpus mod/default-rules))
+(mod-b-test! "coverage has one row per rule" (len mod-b-cov) 6)
+(mod-b-test!
+  "spam-hide fired twice"
+  (mod/rule-fire-count mod-b-decisions "spam-hide")
+  2)
+(mod-b-test!
+  "abuse-remove fired once"
+  (mod/rule-fire-count mod-b-decisions "abuse-remove")
+  1)
+(mod-b-test!
+  "default-keep fired twice"
+  (mod/rule-fire-count mod-b-decisions "default-keep")
+  2)
+
+;; ── never-fired: rules not exercised by this corpus ──
+
+(define mod-b-never (mod/never-fired mod-b-corpus mod/default-rules))
+(mod-b-test!
+  "exonerated-keep never fired"
+  (mod/member? "exonerated-keep" mod-b-never)
+  true)
+(mod-b-test!
+  "reviewer-remove never fired"
+  (mod/member? "reviewer-remove" mod-b-never)
+  true)
+(mod-b-test!
+  "repeated-escalate never fired"
+  (mod/member? "repeated-escalate" mod-b-never)
+  true)
+(mod-b-test!
+  "spam-hide DID fire (not in never-fired)"
+  (mod/member? "spam-hide" mod-b-never)
+  false)
+(mod-b-test!
+  "three rules never fired on this corpus"
+  (len mod-b-never)
+  3)
+
+(define mod-batch-tests-run! (fn () {:failures mod-b-failures :total mod-b-count :passed mod-b-pass :failed mod-b-fail}))

plans/mod-on-sx.md

@@ -16,7 +16,7 @@ federation extension.
 
 ## Status (rolling)
 
-`bash lib/mod/conformance.sh` → **260/260** (roadmap + 10 extensions complete)
+`bash lib/mod/conformance.sh` → **277/277** (roadmap + 11 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 11 — batch triage + corpus analytics** (`lib/mod/batch.sx`, +17).
+  `mod/decide-batch` triages a queue; `mod/action-histogram` summarizes outcomes by
+  action; `mod/rule-coverage` / `mod/never-fired` measure which rules fire across a
+  corpus — the *empirical* complement to lint's static unreachable check (Ext 5):
+  lint finds rules that can't fire, never-fired finds rules that didn't.
 - [x] **Ext 10 — policy what-if / impact** (`lib/mod/whatif.sx`, +13).
   `mod/decision-diff` compares one report's action under two rule sets;
   `mod/policy-impact` runs a batch and returns only the reports whose decision
@@ -191,6 +196,11 @@ lib/mod/fed.sx
 
 ## Progress log
 
+- **Ext 11 — batch triage + corpus analytics, 277/277** (+17). Operational layer:
+  triage a queue, histogram the outcomes, and measure rule coverage over real
+  data. `never-fired` pairs with lint (Ext 5) — static "can't fire" vs empirical
+  "didn't fire" — giving policy authors both views of dead rules. Histogram avoids
+  dict mutation by counting over a fixed action vocabulary.
 - **Ext 10 — policy what-if / impact, 260/260** (+13). Decisions are now
   comparable across rule sets — diff one report, or batch a whole set and surface
   only the flips. Pure SX over `decide-report`, no engine change. Closes the