diff --git a/internal/matrix/playbook.go b/internal/matrix/playbook.go
index 8a160de..d0a6068 100644
--- a/internal/matrix/playbook.go
+++ b/internal/matrix/playbook.go
@@ -49,8 +49,31 @@ const DefaultPlaybookTopK = 3
 // query is similar enough to count." 0.5 lets in genuinely related
 // queries while excluding pure-coincidence neighbors. Caller can
 // override per-request as we learn what works for staffing data.
+//
+// This threshold gates the BOOST path (re-rank in place), which is
+// safe at loose thresholds because boost only modifies results already
+// in regular retrieval. The INJECT path uses a tighter ceiling — see
+// DefaultPlaybookMaxInjectDistance.
 const DefaultPlaybookMaxDistance = 0.5
 
+// DefaultPlaybookMaxInjectDistance is the SHAPE B cosine ceiling for
+// "this past query is similar enough to FORCE its answer into the
+// result set." Tighter than DefaultPlaybookMaxDistance because inject
+// is structurally riskier than boost: it adds a result the embedding
+// didn't surface, so a loose match can cross-pollinate the wrong
+// answer into unrelated queries.
+//
+// Empirical motivation (playbook_lift_003): Q2's recording for an
+// OSHA-30 forklift operator surfaced as warm top-1 for the dental
+// hygienist / RN / software engineer OOD queries because their text
+// vectors fell within 0.5 cosine of "OSHA-30 forklift Wisconsin."
+// 0.20 would have rejected those (implied playbook distances 0.38-0.46)
+// while keeping all 6 paraphrase recoveries (≤ 0.30 implied).
+//
+// Boost path stays at 0.5 — re-ranking results that already retrieved
+// by their own merits is safe even when the playbook match is loose.
+const DefaultPlaybookMaxInjectDistance = 0.20
+
 // PlaybookEntry is what gets stored as metadata on each playbook
 // vector. RecordedAt is captured at write time; callers should not
 // set it (the recorder fills it in).
@@ -174,10 +197,18 @@ type PlaybookHit struct {
 //
 // Returns the (possibly extended) results slice and how many synthetic
 // rows were appended. Caller MUST re-sort + truncate to K afterwards.
-func InjectPlaybookMisses(results []Result, hits []PlaybookHit) ([]Result, int) {
+//
+// maxInjectDist filters which hits qualify for injection — hits whose
+// playbook-corpus cosine distance exceeds it are skipped (the boost
+// path may still re-rank them in place). Pass 0 (or any non-positive
+// value) to use DefaultPlaybookMaxInjectDistance.
+func InjectPlaybookMisses(results []Result, hits []PlaybookHit, maxInjectDist float32) ([]Result, int) {
 	if len(hits) == 0 {
 		return results, 0
 	}
+	if maxInjectDist <= 0 {
+		maxInjectDist = float32(DefaultPlaybookMaxInjectDistance)
+	}
 	present := make(map[string]bool, len(results))
 	for _, r := range results {
 		present[r.Corpus+"|"+r.ID] = true
@@ -188,6 +219,13 @@ func InjectPlaybookMisses(results []Result, hits []PlaybookHit) ([]Result, int)
 	// Multiple hits to the same answer collapse to one injection.
 	bestForKey := make(map[string]PlaybookHit)
 	for _, h := range hits {
+		// Inject-specific tighter threshold (boost path's threshold is
+		// looser; this prevents cross-pollination of wrong-domain
+		// answers into queries whose text happens to fall within
+		// boost-distance of an unrelated recording).
+		if h.Distance > maxInjectDist {
+			continue
+		}
 		key := h.Entry.AnswerCorpus + "|" + h.Entry.AnswerID
 		if present[key] {
 			continue
diff --git a/internal/matrix/playbook_test.go b/internal/matrix/playbook_test.go
index 1cf9e57..b2ba3fe 100644
--- a/internal/matrix/playbook_test.go
+++ b/internal/matrix/playbook_test.go
@@ -187,7 +187,7 @@ func TestInjectPlaybookMisses_AddsMissingAnswers(t *testing.T) {
 			},
 		},
 	}
-	out, injected := InjectPlaybookMisses(results, hits)
+	out, injected := InjectPlaybookMisses(results, hits, 0)
 	if injected != 1 {
 		t.Fatalf("expected 1 injected, got %d", injected)
 	}
@@ -240,7 +240,7 @@ func TestInjectPlaybookMisses_SkipsAnswersAlreadyPresent(t *testing.T) {
 			},
 		},
 	}
-	out, injected := InjectPlaybookMisses(results, hits)
+	out, injected := InjectPlaybookMisses(results, hits, 0)
 	if injected != 0 {
 		t.Errorf("expected 0 injected (answer already present), got %d", injected)
 	}
@@ -266,7 +266,7 @@ func TestInjectPlaybookMisses_DedupesPerAnswer(t *testing.T) {
 			Entry:      PlaybookEntry{QueryText: "q2", AnswerID: "w-99", AnswerCorpus: "workers", Score: 1.0},
 		},
 	}
-	out, injected := InjectPlaybookMisses(results, hits)
+	out, injected := InjectPlaybookMisses(results, hits, 0.5) // explicit loose threshold so 0.30 hits qualify
 	if injected != 1 {
 		t.Errorf("expected 1 injection (deduped), got %d", injected)
 	}
@@ -280,10 +280,51 @@ func TestInjectPlaybookMisses_DedupesPerAnswer(t *testing.T) {
 	}
 }
 
+// TestInjectPlaybookMisses_RespectsInjectThreshold locks the
+// cross-pollination defense added after run #003: hits whose playbook
+// distance exceeds the inject threshold are skipped, preventing the
+// "OSHA-30 forklift" recording from surfacing as warm top-1 for an
+// unrelated dental-hygienist query just because their text vectors
+// happened to fall within boost-threshold (0.5).
+func TestInjectPlaybookMisses_RespectsInjectThreshold(t *testing.T) {
+	results := []Result{{ID: "w-1", Corpus: "workers", Distance: 0.30}}
+	// Two hits: one within tight inject threshold, one beyond it but
+	// within boost threshold. Only the tight one should inject.
+	hits := []PlaybookHit{
+		{
+			PlaybookID: "tight",
+			Distance:   0.10, // within inject (true paraphrase territory)
+			Entry:      PlaybookEntry{QueryText: "q1", AnswerID: "w-tight", AnswerCorpus: "workers", Score: 1.0},
+		},
+		{
+			PlaybookID: "loose",
+			Distance:   0.40, // boost-eligible but inject-rejected
+			Entry:      PlaybookEntry{QueryText: "q2", AnswerID: "w-loose", AnswerCorpus: "workers", Score: 1.0},
+		},
+	}
+	// Default threshold (0 → DefaultPlaybookMaxInjectDistance = 0.20)
+	out, injected := InjectPlaybookMisses(results, hits, 0)
+	if injected != 1 {
+		t.Errorf("expected 1 injection (only the tight hit qualifies), got %d", injected)
+	}
+	gotTight := false
+	for _, r := range out {
+		if r.ID == "w-tight" {
+			gotTight = true
+		}
+		if r.ID == "w-loose" {
+			t.Errorf("loose hit (distance > inject threshold) was injected anyway")
+		}
+	}
+	if !gotTight {
+		t.Error("tight hit should have been injected")
+	}
+}
+
 // TestInjectPlaybookMisses_EmptyHits is a fast-path no-op check.
 func TestInjectPlaybookMisses_EmptyHits(t *testing.T) {
 	results := []Result{{ID: "w-1", Corpus: "workers", Distance: 0.30}}
-	out, injected := InjectPlaybookMisses(results, nil)
+	out, injected := InjectPlaybookMisses(results, nil, 0)
 	if injected != 0 {
 		t.Errorf("expected 0 injection, got %d", injected)
 	}
diff --git a/internal/matrix/retrieve.go b/internal/matrix/retrieve.go
index 625f08f..351749f 100644
--- a/internal/matrix/retrieve.go
+++ b/internal/matrix/retrieve.go
@@ -53,8 +53,14 @@ type Result struct {
 //   PlaybookCorpus: index name; empty = DefaultPlaybookCorpus.
 //   PlaybookTopK: number of similar past queries to consider; 0 =
 //     DefaultPlaybookTopK.
-//   PlaybookMaxDistance: cosine ceiling for "similar enough"; 0 =
-//     DefaultPlaybookMaxDistance.
+//   PlaybookMaxDistance: cosine ceiling for "similar enough" on the
+//     BOOST path (re-rank in place); 0 = DefaultPlaybookMaxDistance.
+//   PlaybookMaxInjectDistance: tighter cosine ceiling for the SHAPE B
+//     INJECT path; 0 = DefaultPlaybookMaxInjectDistance. Splitting the
+//     two thresholds is intentional — boost is safe at loose thresholds
+//     because it only re-ranks results that already retrieved on their
+//     own merits, while inject forces results in and so cross-pollinates
+//     wrong-domain answers if the threshold is too loose.
 //
 // Metadata filter (post-retrieval structured gate):
 //   MetadataFilter: map of metadata-field → expected value. Results
@@ -76,8 +82,9 @@ type SearchRequest struct {
 	UsePlaybook         bool           `json:"use_playbook,omitempty"`
 	PlaybookCorpus      string         `json:"playbook_corpus,omitempty"`
 	PlaybookTopK        int            `json:"playbook_top_k,omitempty"`
-	PlaybookMaxDistance float64        `json:"playbook_max_distance,omitempty"`
-	MetadataFilter      map[string]any `json:"metadata_filter,omitempty"`
+	PlaybookMaxDistance       float64        `json:"playbook_max_distance,omitempty"`
+	PlaybookMaxInjectDistance float64        `json:"playbook_max_inject_distance,omitempty"`
+	MetadataFilter            map[string]any `json:"metadata_filter,omitempty"`
 }
 
 // SearchResponse wraps the merged results plus per-corpus return
@@ -233,8 +240,12 @@ func (r *Retriever) Search(ctx context.Context, req SearchRequest) (*SearchRespo
 			slog.Warn("matrix: playbook lookup failed; skipping boost+inject", "err", err)
 		} else if len(hits) > 0 {
 			resp.PlaybookBoosted = ApplyPlaybookBoost(resp.Results, hits)
+			maxInjectDist := float32(req.PlaybookMaxInjectDistance)
+			if maxInjectDist <= 0 {
+				maxInjectDist = float32(DefaultPlaybookMaxInjectDistance)
+			}
 			var injected int
-			resp.Results, injected = InjectPlaybookMisses(resp.Results, hits)
+			resp.Results, injected = InjectPlaybookMisses(resp.Results, hits, maxInjectDist)
 			resp.PlaybookInjected = injected
 			if injected > 0 {
 				// Re-sort + truncate after injection. ApplyPlaybookBoost
diff --git a/reports/reality-tests/playbook_lift_004.md b/reports/reality-tests/playbook_lift_004.md
new file mode 100644
index 0000000..c1e5008
--- /dev/null
+++ b/reports/reality-tests/playbook_lift_004.md
@@ -0,0 +1,117 @@
+# Playbook-Lift Reality Test — Run 004
+
+**Generated:** 2026-04-30T12:23:36.594892386Z
+**Judge:** `qwen2.5:latest` (Ollama, resolved from env JUDGE_MODEL=qwen2.5:latest)
+**Corpora:** `workers,ethereal_workers`
+**Workers limit:** 5000
+**Queries:** `tests/reality/playbook_lift_queries.txt` (21 executed)
+**K per pass:** 10
+**Paraphrase pass:** ENABLED
+**Evidence:** `reports/reality-tests/playbook_lift_004.json`
+
+---
+
+## Headline
+
+| Metric | Value |
+|---|---:|
+| Total queries run | 21 |
+| Cold-pass discoveries (judge-best ≠ top-1) | 8 |
+| Warm-pass lifts (recorded playbook → top-1) | 6 |
+| No change (judge-best already top-1, no playbook needed) | 15 |
+| Playbook boosts triggered (warm pass) | 8 |
+| Mean Δ top-1 distance (warm − cold) | -0.070719235 |
+| **Paraphrase pass — recorded answer at rank 0 (top-1)** | **6 / 8** |
+| Paraphrase pass — recorded answer at any rank in top-K | 6 / 8 |
+
+**Verbatim lift rate:** 6 of 8 discoveries became top-1 after warm pass.
+
+---
+
+## Per-query results
+
+| # | Query | Cold top-1 | Cold judge-best (rank/rating) | Recorded? | Warm top-1 | Judge-best warm rank | Lift |
+|---|---|---|---|---|---|---|---|
+| 1 | Forklift operator with OSHA-30, warehouse experience, day sh | e-4983 | 1/4 | ✓ e-5729 | e-5729 | 0 | **YES** |
+| 2 | OSHA-30 certified forklift operator in Wisconsin, cold stora | e-868 | 9/3 | — | e-7308 | -1 | no |
+| 3 | Production worker with confined-space cert and hazmat traini | w-4583 | 1/2 | — | w-1231 | 2 | no |
+| 4 | CDL Class A driver, clean record, willing to do regional 4-d | w-3272 | 0/1 | — | w-3272 | 0 | no |
+| 5 | Warehouse lead with current OSHA-30 certification, NOT OSHA- | w-2356 | 3/2 | — | w-2356 | 3 | no |
+| 6 | Forklift-certified loader, certification must be active, dis | e-3940 | 3/4 | ✓ w-330 | e-7453 | 1 | no |
+| 7 | Hazmat-certified warehouse worker comfortable with cold stor | w-4633 | 4/4 | ✓ e-7453 | w-330 | 1 | no |
+| 8 | Bilingual production worker with team-lead experience and tr | w-2983 | 0/4 | — | w-2983 | 0 | no |
+| 9 | Inventory specialist with confined-space cert and compliance | w-3037 | 7/4 | ✓ w-1231 | w-1231 | 0 | **YES** |
+| 10 | Warehouse worker who can run inventory cycles and lead a sma | e-6649 | 1/4 | ✓ w-4113 | w-4113 | 0 | **YES** |
+| 11 | Production line worker comfortable filling in as line superv | w-1010 | 3/4 | ✓ w-1153 | w-1153 | 0 | **YES** |
+| 12 | Customer service rep willing to cross-train into dispatch or | e-6474 | 1/2 | — | e-6474 | 1 | no |
+| 13 | Reliable production line lead with strong attendance and lea | e-4284 | 0/3 | — | e-4284 | 0 | no |
+| 14 | Highly responsive forklift operator available for last-minut | e-285 | 4/4 | ✓ e-7308 | e-7308 | 0 | **YES** |
+| 15 | Engaged warehouse associate with strong safety compliance re | e-8404 | 5/4 | ✓ w-3242 | w-3242 | 0 | **YES** |
+| 16 | CDL-A driver based in IL or WI, willing to run regional 4-da | w-3257 | 4/2 | — | w-3257 | 4 | no |
+| 17 | Bilingual customer service rep in Indianapolis or Cincinnati | w-1387 | 0/1 | — | w-1387 | 0 | no |
+| 18 | Production supervisor open to Midwest relocation for permane | e-7478 | 1/2 | — | e-7478 | 1 | no |
+| 19 | Dental hygienist with three years experience, Indianapolis a | e-2544 | 0/1 | — | e-2544 | 0 | no |
+| 20 | Registered nurse with ICU experience, willing to take per-di | w-419 | 0/1 | — | w-419 | 0 | no |
+| 21 | Software engineer with React and TypeScript, three years exp | w-334 | 0/1 | — | w-334 | 0 | no |
+
+---
+
+## Paraphrase pass — does the playbook help similar-but-different queries?
+
+For each query whose Pass 1 cold pass recorded a playbook entry, the
+judge model rephrased the query, and the rephrased version was sent
+through warm matrix.search. The recorded answer ID's rank in those
+results tests whether cosine on the embedded paraphrase finds the
+recorded query's vector.
+
+| # | Original (≤40c) | Paraphrase (≤60c) | Recorded answer | Paraphrase top-1 | Recorded rank | Paraphrase lift |
+|---|---|---|---|---|---|---|
+| 1 | Forklift operator with OSHA-30, warehous | Seeking forklift operator certified in OSHA-30, with backgro | e-5729 | e-5729 | 0 | **YES** |
+| 6 | Forklift-certified loader, certification | Loader with active forklift certification, separate from reg | w-330 | w-330 | 0 | **YES** |
+| 7 | Hazmat-certified warehouse worker comfor | Warehouse worker with Hazmat certification and experience in | e-7453 | e-7453 | 0 | **YES** |
+| 9 | Inventory specialist with confined-space | Individual needed for inventory management with certificatio | w-1231 | w-987 | -1 | no |
+| 10 | Warehouse worker who can run inventory c | Seeking a warehouse worker capable of conducting inventory c | w-4113 | w-4113 | 0 | **YES** |
+| 11 | Production line worker comfortable filli | Seeking a production line worker capable of temporarily step | w-1153 | w-1153 | 0 | **YES** |
+| 14 | Highly responsive forklift operator avai | Available for urgent forklift operation shifts requiring imm | e-7308 | e-7308 | 0 | **YES** |
+| 15 | Engaged warehouse associate with strong  | Warehouse associate currently engaged with a robust history  | w-3242 | e-2615 | -1 | no |
+
+---
+
+## Honesty caveats
+
+1. **Judge IS the ground truth proxy.** Without human-labeled relevance, the LLM
+   judge's verdict is what defines "best." If `qwen2.5:latest` rates badly,
+   the lift number is meaningless. To validate the judge itself, sample 5–10
+   verdicts manually and check agreement.
+2. **Score-1.0 boost = distance halved.** Playbook math is
+   `distance' = distance × (1 - 0.5 × score)`. Lift requires the judge-best
+   result's pre-boost distance to be ≤ 2× the cold top-1's distance, otherwise
+   even halving doesn't promote it. Tight clusters → little visible lift.
+3. **Verbatim vs paraphrase.** The verbatim lift rate (above) is the cheap
+   case — same query, recorded playbook, expected boost. The paraphrase
+   pass (when enabled) is the actual learning property: similar-but-different
+   queries hitting a recorded playbook. Compare verbatim and paraphrase
+   lift rates — paraphrase should be lower (semantic-distance gates some
+   playbook hits) but non-zero is the meaningful signal.
+4. **Multi-corpus skew.** Default corpora=`workers,ethereal_workers` — if all judge-best
+   results land in one corpus, the matrix layer's purpose isn't being tested.
+   Check per-corpus distribution in the JSON.
+5. **Judge resolution.** This run used `qwen2.5:latest` from
+   env JUDGE_MODEL=qwen2.5:latest.
+   Bumping the judge for run #N+1 means editing one line in lakehouse.toml.
+6. **Paraphrase generation also uses the judge.** The same model that rates
+   relevance also rephrases queries. A judge that's bad at rating staffing
+   queries is probably also bad at rephrasing them. Worth sanity-checking
+   a sample of `paraphrase_query` values in the JSON before trusting the
+   paraphrase lift number.
+
+## Next moves
+
+- If lift rate ≥ 50% of discoveries: matrix layer + playbook is doing real
+  work. Move to paraphrase queries + tag-based boost (currently ignored).
+- If lift rate < 20%: investigate why — judge variance, distance gap too
+  wide, or playbook math too gentle. The score=1.0 / 0.5× formula may need
+  retuning.
+- If discovery rate (cold judge-best ≠ top-1) is itself low: cosine is
+  already close to optimal on this query distribution. Either the corpus
+  is too narrow or the queries are too easy.