diff --git a/commands/ab-test.md b/commands/ab-test.md
index 8201508..cc589c9 100644
--- a/commands/ab-test.md
+++ b/commands/ab-test.md
@@ -125,7 +125,7 @@ Generate a posting schedule that alternates A/B on comparable days:
 - Use the user's typical posting days (from state file or ask)
 - Alternate variants across the same day slots each week
 - Default: 3 posts per variant across 2 weeks (6 total)
-- Suggest posting times based on algorithm-signals-reference.md (Tue-Thu, 8-9 AM optimal)
+- Suggest posting times based on algorithm-signals-reference.md (Tue-Thu mornings)
 
 ### 2a.6: Set Success Criteria
 
diff --git a/docs/hardening/log.md b/docs/hardening/log.md
index 98c6cd0..f552c9d 100644
--- a/docs/hardening/log.md
+++ b/docs/hardening/log.md
@@ -1344,3 +1344,62 @@ weaker relevance match → less reach is defensible and "topic-relevance signal"
 - Disposition: **FIXED** (2 edits, `commands/audit.md`) · 0 deferrals · axes a/c PASS, b′ + d PASS post-fix.
 
 ---
+
+### /linkedin:ab-test — design/log/analyze/history/suggest A/B experiments → managed test files, challenger rewrite delegated to content-optimizer
+
+**INTENT.** Stateful analytics command — the most composite class in the queue so far. CLI-backed (Bash
+`ls`/`cat`/`mkdir -p` + `Write` of `[test-name].md` test files under the data-dir), agent-delegated
+(`content-optimizer` via `Task subagent_type: linkedin-studio:content-optimizer`, `:119`), AND routing
+(`/linkedin:post` `:448`, `/linkedin:report` `:459`, `/linkedin:analyze` `:467`). Measure-journey
+(reachable via `/linkedin:measure`). Five lifecycle modes (2a–2e) map 1:1 to the description: design ·
+log · analyze · history · suggest. (STATE predicted `analytics-interpreter` delegation; actual is
+`content-optimizer`.)
+
+**SIMULATE.** ICP author → analyze an active hook experiment. Throwaway 2-experiment fixture in
+`/private/tmp/claude-abtest-fixture/analytics/ab-tests/` (ACTIVE 6-post + COMPLETED), run via
+`LINKEDIN_STUDIO_DATA=<fixture>` to exercise the real seam. Seam-discovery (`:37`,`:270`) found both
+files; analyze arithmetic computed correct (eng-rate `:236` per-post 3.0%/5.0%; variant avg + %-diff
+`:278–279` → eng +66.7%, comments +200%, impressions/reposts +0%); directional test (`:311`) cleared
+20% AND consistent across all 3 paired posts → "Adopt B (directional)"; significance honesty (`:320–331`)
+correctly flagged 3/variant << ~50 → directional, NOT significant. History-parse targets all present in
+COMPLETED fixture. Empty `weekly-reports/` + `posts/` → graceful degradation (`:485–488`). Fixture
+discarded (`find -delete`).
+
+**EVALUATE (8 predicates across 4 axes; class = stateful + analytics + agent-wiring + routing).**
+- **P1 (axis-d wiring): PASS** — `content-optimizer` resolves; `agents/content-optimizer.md` `name:`
+  matches the namespaced invocation form.
+- **P2 (routing): PASS** — `post`/`report`/`analyze`.md all resolve.
+- **P3 (intent refs): PASS** — `ab-testing-framework.md` + `algorithm-signals-reference.md` exist.
+- **P4 (axis-b′ SSOT): 1 FUNN.** ② 20%-threshold **verbatim** from framework SSOT (`fw:173` = `ab:311`)
+  ✅; ③ significance honesty under-claims (a real significance test needs more than ~50/variant → the
+  framing can only make the "directional not significant" verdict safer) ✅; **① `:128` "(Tue-Thu, 8-9 AM
+  optimal)"** — sourced (cites the ref) but "optimal" over-claims precision against the SSOT's own `:23`
+  "trust the *ordering*, test the *number*", and Thu is 9 AM–1 PM in SSOT (`alg:144`), not 8 AM; it is the
+  default slot held constant while testing another variable, so "optimal" is the wrong word.
+- **P5 (data-seam): PASS** — all data via `${LINKEDIN_STUDIO_DATA:-…}/`; `:44` = state file (correct), not
+  a leak; refs via `${CLAUDE_PLUGIN_ROOT}/`.
+- **P6 (graceful degradation): PASS** — empty weekly-reports/posts → proceed test-only (`:485–488`); 4
+  error modes (`:474–493`).
+- **P7 (saves/dwell honesty): PASS** — no saves/dwell mention; eng-rate `:236` excludes saves (S16-consistent).
+- **P8 (stateful artifact trace): PASS** — see SIMULATE; full analyze + history path sound against a
+  realistic file.
+
+**HARDEN (1 surgical edit, `commands/ab-test.md`).**
+1. [REWORK · axis-b′] `:128` "(Tue-Thu, 8-9 AM optimal)" → "(Tue-Thu mornings)" — dropped the precision
+   over-claim ("optimal" + the inaccurate 8 AM window); the line stem already cites
+   `algorithm-signals-reference.md`, so source attribution is retained.
+
+**Out-of-scope (logged, NOT touched in S18).** `:284` "baseline comparison" cross-ref vs `weekly-reports/`
+— echoes the S15 "baselines/metadata phantom" vocabulary, but here it reads an existing artifact (the
+report command's weekly reports), optional + graceful-degraded; legitimate soft context, not a phantom.
+Left as-is (low, no-change).
+
+**VERIFY.**
+- Re-grepped final file: `grep "8-9 AM optimal"` → **NONE**; `:128` = "...based on
+  algorithm-signals-reference.md (Tue-Thu mornings)".
+- `git diff --stat` = 1 file, **+1 / −1**.
+- `bash scripts/test-runner.sh` → `Passed: 81 · Failed: 0 · Warnings: 0`, **exit 0**; counts **29/19**
+  unchanged (.md-only edit).
+- Disposition: **FIXED** (1 edit, `commands/ab-test.md`) · 0 deferrals · P1–P3,P5–P8 PASS, P4 PASS post-fix.
+
+---