diff --git a/config/modes.toml b/config/modes.toml
index 42145f3..e021a2f 100644
--- a/config/modes.toml
+++ b/config/modes.toml
@@ -12,8 +12,13 @@
 
 [[task_class]]
 name = "scrum_review"
-preferred_mode = "codereview"
-fallback_modes = ["consensus", "ladder"]
+# `codereview_lakehouse` is the codebase-specific enrichment runner —
+# bundles defined/imported symbols, pathway-memory bug fingerprints,
+# and relevance-filtered matrix chunks into ONE precise prompt so the
+# model gets it right the first call. The generic `codereview` mode
+# from LLM Team is still the network fallback if execute fails.
+preferred_mode = "codereview_lakehouse"
+fallback_modes = ["codereview", "consensus", "ladder"]
 default_model = "qwen3-coder:480b"
 matrix_corpus = "distilled_procedural_v20260423102847"
 
diff --git a/crates/gateway/src/v1/mod.rs b/crates/gateway/src/v1/mod.rs
index 482c79e..b477d86 100644
--- a/crates/gateway/src/v1/mod.rs
+++ b/crates/gateway/src/v1/mod.rs
@@ -86,6 +86,7 @@ pub fn router(state: V1State) -> Router {
         .route("/context", get(truth::context))
         .route("/mode", post(mode::route))
         .route("/mode/list", get(mode::list))
+        .route("/mode/execute", post(mode::execute))
         .with_state(state)
 }
 
diff --git a/crates/gateway/src/v1/mode.rs b/crates/gateway/src/v1/mode.rs
index 834de12..294ccd7 100644
--- a/crates/gateway/src/v1/mode.rs
+++ b/crates/gateway/src/v1/mode.rs
@@ -29,14 +29,29 @@ use super::V1State;
 /// Validated against the LLM Team /api/run handler at
 /// /root/llm_team_ui.py:10581. Kept in sync manually — adding a mode
 /// here without adding it upstream returns 400 from the proxy.
+///
+/// Modes prefixed with the codebase name (e.g. `codereview_lakehouse`)
+/// are NATIVE Rust enrichment runners — they don't proxy to LLM Team,
+/// they compose the lakehouse's own context primitives (pathway memory,
+/// relevance filter, matrix corpora) into a one-shot prompt for the
+/// recommended model. Native modes are listed alongside upstream ones
+/// so the router can pick either without callers caring.
 const VALID_MODES: &[&str] = &[
     "brainstorm", "pipeline", "debate", "validator", "roundrobin",
     "redteam", "consensus", "codereview", "ladder", "tournament",
     "evolution", "blindassembly", "staircase", "drift", "mesh",
     "hallucination", "timeloop", "research", "eval", "extract",
     "refine", "adaptive", "deep_analysis", "distill",
+    // Native runners (not in LLM Team — handled by /v1/mode/execute):
+    "codereview_lakehouse",
 ];
 
+/// Whether a mode is handled natively in this gateway vs proxied to
+/// LLM Team. Drives /v1/mode/execute dispatch.
+fn is_native_mode(mode: &str) -> bool {
+    matches!(mode, "codereview_lakehouse")
+}
+
 #[derive(Clone, Debug, Deserialize)]
 pub struct TaskClassEntry {
     pub name: String,
@@ -283,6 +298,388 @@ pub async fn list(State(_state): State<V1State>) -> impl IntoResponse {
     }))
 }
 
+// ─── Native runner: codereview_lakehouse ───
+//
+// Enrichment composer for the lakehouse-specific code review mode.
+// Pulls every context primitive the gateway exposes — focus file
+// content, pathway-memory bug fingerprints, matrix corpus chunks
+// (post relevance filter) — bundles them into ONE prompt designed
+// for one-shot success against qwen3-coder:480b. The whole point of
+// the mode is that the model gets it right the first time because
+// the prompt was molded for THIS file in THIS codebase.
+//
+// Network composition only — no Rust port of the relevance scorer.
+// Every primitive is already an HTTP endpoint; the runner just stitches.
+
+#[derive(Deserialize, Debug)]
+pub struct ExecuteRequest {
+    pub task_class: String,
+    pub file_path: String,
+    /// If absent, the runner reads the file from disk relative to the
+    /// gateway working directory. Useful for test harnesses that don't
+    /// want to rely on filesystem state.
+    #[serde(default)]
+    pub file_content: Option<String>,
+    /// Override the resolved mode — same semantics as RouteRequest.
+    #[serde(default)]
+    pub force_mode: Option<String>,
+    /// Override the resolved model. Defaults to the task_class's
+    /// default_model from modes.toml.
+    #[serde(default)]
+    pub force_model: Option<String>,
+    /// Reserved for ad-hoc questions about the file. If omitted, the
+    /// runner uses its built-in forensic-review framing.
+    #[serde(default)]
+    pub user_question: Option<String>,
+}
+
+#[derive(Serialize, Debug, Default)]
+pub struct EnrichmentSources {
+    pub focus_file_bytes: usize,
+    pub bug_fingerprints_count: usize,
+    pub matrix_chunks_kept: usize,
+    pub matrix_chunks_dropped: usize,
+    pub matrix_corpus: Option<String>,
+    pub relevance_filter_used: bool,
+    pub enrichment_warnings: Vec<String>,
+}
+
+#[derive(Serialize, Debug)]
+pub struct ExecuteResponse {
+    pub mode: String,
+    pub model: String,
+    pub task_class: String,
+    pub enriched_prompt_chars: usize,
+    pub enriched_prompt_preview: String,
+    pub sources: EnrichmentSources,
+    pub response: String,
+    pub latency_ms: u64,
+}
+
+const REVIEWER_FRAMING: &str = "You are an adversarial code reviewer for the Lakehouse codebase \
+(Rust + DataFusion + Parquet + object storage). Audit the focus file forensically. \
+Output a markdown report with: (1) one-line verdict (pass | needs_patch | fail), (2) ranked \
+findings table with file:line, evidence, severity, confidence percent, (3) concrete patch \
+suggestions, (4) PRD/ADR refs where applicable. Be precise — assume nothing works until \
+proven. Do NOT hedge.";
+
+pub async fn execute(
+    State(_state): State<V1State>,
+    Json(req): Json<ExecuteRequest>,
+) -> impl IntoResponse {
+    let cfg = load_config();
+    let t0 = std::time::Instant::now();
+
+    // Resolve mode + model (mirrors /v1/mode logic).
+    let tc = cfg.lookup(&req.task_class);
+    let mode = req
+        .force_mode
+        .clone()
+        .or_else(|| tc.map(|t| t.preferred_mode.clone()))
+        .unwrap_or_else(|| cfg.default.preferred_mode.clone());
+    let model = req
+        .force_model
+        .clone()
+        .or_else(|| tc.map(|t| t.default_model.clone()))
+        .unwrap_or_else(|| cfg.default.default_model.clone());
+    let matrix_corpus = tc.and_then(|t| t.matrix_corpus.clone());
+
+    if !is_native_mode(&mode) {
+        // Native execute is the only path implemented; LLM-Team proxy
+        // is queued behind this. Surface a clear 501 so callers know.
+        return Err((
+            StatusCode::NOT_IMPLEMENTED,
+            Json(serde_json::json!({
+                "error": format!(
+                    "mode '{}' has no native runner — proxy to /api/run not yet wired",
+                    mode
+                ),
+                "hint": "use force_mode=codereview_lakehouse, or call LLM Team /api/run directly until proxy lands",
+            })),
+        ));
+    }
+
+    let mut sources = EnrichmentSources {
+        matrix_corpus: matrix_corpus.clone(),
+        ..Default::default()
+    };
+
+    // Step 1: focus file content.
+    let file_content = match req.file_content.clone() {
+        Some(c) => c,
+        None => match std::fs::read_to_string(&req.file_path) {
+            Ok(c) => c,
+            Err(e) => {
+                return Err((
+                    StatusCode::BAD_REQUEST,
+                    Json(serde_json::json!({
+                        "error": format!("read {} failed: {}", req.file_path, e),
+                    })),
+                ));
+            }
+        },
+    };
+    sources.focus_file_bytes = file_content.len();
+
+    // Local HTTP client for composing internal calls. Short timeout
+    // because every endpoint is on localhost; the LLM call uses its
+    // own longer timeout further down.
+    let client = match reqwest::Client::builder()
+        .timeout(std::time::Duration::from_secs(8))
+        .build()
+    {
+        Ok(c) => c,
+        Err(e) => {
+            return Err((
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(serde_json::json!({"error": format!("client build: {e}")})),
+            ));
+        }
+    };
+
+    // Step 2: pathway memory bug fingerprints for this file area.
+    let mut bug_preamble = String::new();
+    {
+        let body = serde_json::json!({
+            "task_class": req.task_class,
+            "file_path": req.file_path,
+            "signal_class": null,
+            "limit": 10,
+        });
+        match client
+            .post("http://localhost:3100/vectors/pathway/bug_fingerprints")
+            .json(&body)
+            .send()
+            .await
+        {
+            Ok(r) if r.status().is_success() => {
+                if let Ok(j) = r.json::<serde_json::Value>().await {
+                    let fps = j.get("fingerprints").and_then(|v| v.as_array()).cloned().unwrap_or_default();
+                    sources.bug_fingerprints_count = fps.len();
+                    if !fps.is_empty() {
+                        bug_preamble.push_str(
+                            "📚 PATHWAY MEMORY — BUGS PREVIOUSLY FOUND IN THIS FILE AREA:\n",
+                        );
+                        for fp in &fps {
+                            let pk = fp.get("pattern_key").and_then(|v| v.as_str()).unwrap_or("?");
+                            let occ = fp.get("occurrences").and_then(|v| v.as_u64()).unwrap_or(0);
+                            let ex = fp.get("example").and_then(|v| v.as_str()).unwrap_or("");
+                            bug_preamble.push_str(&format!(
+                                "  • {} (×{}) e.g. `{}`\n",
+                                pk, occ, ex
+                            ));
+                        }
+                        bug_preamble.push_str("Watch for these patterns recurring.\n\n");
+                    }
+                }
+            }
+            Ok(r) => sources
+                .enrichment_warnings
+                .push(format!("bug_fingerprints HTTP {}", r.status())),
+            Err(e) => sources
+                .enrichment_warnings
+                .push(format!("bug_fingerprints err: {e}")),
+        }
+    }
+
+    // Step 3: matrix corpus search (if configured for this task class).
+    let mut raw_chunks: Vec<serde_json::Value> = vec![];
+    if let Some(corpus) = &matrix_corpus {
+        let body = serde_json::json!({
+            "index_name": corpus,
+            "query": format!("{} {}\n{}", req.task_class, req.file_path, &file_content[..file_content.len().min(500)]),
+            "top_k": 8,
+        });
+        match client
+            .post("http://localhost:3100/vectors/search")
+            .json(&body)
+            .send()
+            .await
+        {
+            Ok(r) if r.status().is_success() => {
+                if let Ok(j) = r.json::<serde_json::Value>().await {
+                    raw_chunks = j
+                        .get("results")
+                        .and_then(|v| v.as_array())
+                        .cloned()
+                        .unwrap_or_default();
+                }
+            }
+            Ok(r) => sources
+                .enrichment_warnings
+                .push(format!("matrix_search HTTP {}", r.status())),
+            Err(e) => sources
+                .enrichment_warnings
+                .push(format!("matrix_search err: {e}")),
+        }
+    }
+
+    // Step 4: relevance filter — drop adjacency pollution.
+    let kept_chunks: Vec<serde_json::Value> = if !raw_chunks.is_empty() {
+        let chunks_for_filter: Vec<serde_json::Value> = raw_chunks
+            .iter()
+            .map(|c| {
+                serde_json::json!({
+                    "source": c.get("source").cloned().unwrap_or_default(),
+                    "doc_id": c.get("doc_id").cloned().unwrap_or_default(),
+                    "text": c.get("chunk_text").or_else(|| c.get("text")).cloned().unwrap_or_default(),
+                    "score": c.get("score").cloned().unwrap_or(serde_json::json!(0.0)),
+                })
+            })
+            .collect();
+        let body = serde_json::json!({
+            "focus_file": { "path": req.file_path, "content": file_content },
+            "chunks": chunks_for_filter,
+            "threshold": 0.3,
+        });
+        match client
+            .post("http://localhost:3800/relevance")
+            .json(&body)
+            .send()
+            .await
+        {
+            Ok(r) if r.status().is_success() => {
+                sources.relevance_filter_used = true;
+                if let Ok(j) = r.json::<serde_json::Value>().await {
+                    let kept = j.get("kept").and_then(|v| v.as_array()).cloned().unwrap_or_default();
+                    let dropped = j.get("dropped").and_then(|v| v.as_array()).cloned().unwrap_or_default();
+                    sources.matrix_chunks_kept = kept.len();
+                    sources.matrix_chunks_dropped = dropped.len();
+                    kept
+                } else {
+                    raw_chunks
+                }
+            }
+            _ => {
+                sources
+                    .enrichment_warnings
+                    .push("relevance filter unreachable, using raw chunks".to_string());
+                raw_chunks
+            }
+        }
+    } else {
+        vec![]
+    };
+
+    // Step 5: assemble the prompt.
+    let mut user_prompt = String::new();
+    user_prompt.push_str(&bug_preamble);
+    if !kept_chunks.is_empty() {
+        user_prompt.push_str("📁 RELATED CONTEXT (relevance-filtered from matrix):\n");
+        for c in &kept_chunks {
+            let src = c.get("source").and_then(|v| v.as_str()).unwrap_or("?");
+            let txt = c.get("text").and_then(|v| v.as_str()).unwrap_or("");
+            user_prompt.push_str(&format!("  [{}] {}\n", src, &txt[..txt.len().min(280)]));
+        }
+        user_prompt.push_str("\n");
+    }
+    user_prompt.push_str(&format!("FILE: {}\n```rust\n{}\n```\n", req.file_path, file_content));
+    if let Some(q) = &req.user_question {
+        user_prompt.push_str(&format!("\nQUESTION: {}\n", q));
+    } else {
+        user_prompt.push_str("\nProduce the forensic review now.\n");
+    }
+
+    let enriched_chars = user_prompt.len();
+    let preview: String = user_prompt.chars().take(800).collect();
+
+    // Step 6: ONE call to /v1/chat. The whole point of the mode is
+    // that this single call gets it right because the prompt was
+    // molded for THIS file. No retry ladder.
+    //
+    // Provider selection mirrors routing.toml's broad strokes — Phase 40
+    // routing engine isn't auto-wired into /v1/chat yet, so the runner
+    // hints explicitly. Cloud-only models (kimi*, qwen3-coder*,
+    // deepseek*, mistral-large*, gpt-oss:120b, qwen3.5:397b) → cloud;
+    // smaller local-resident models → local ollama default.
+    let provider_hint = if model.contains('/') || model.contains(":free") {
+        // OpenRouter convention: vendor/model[:tag] (e.g.
+        // "openai/gpt-oss-120b:free", "google/gemma-3-27b-it:free").
+        "openrouter"
+    } else if model.starts_with("kimi-")
+        || model.starts_with("qwen3-coder")
+        || model.starts_with("deepseek-v")
+        || model.starts_with("mistral-large")
+        || model == "gpt-oss:120b"
+        || model == "qwen3.5:397b"
+    {
+        "ollama_cloud"
+    } else {
+        "ollama"
+    };
+    let chat_body = serde_json::json!({
+        "model": model,
+        "provider": provider_hint,
+        "messages": [
+            { "role": "system", "content": REVIEWER_FRAMING },
+            { "role": "user", "content": user_prompt },
+        ],
+        "temperature": 0.1,
+        "max_tokens": 4096,
+    });
+    let chat_client = match reqwest::Client::builder()
+        .timeout(std::time::Duration::from_secs(180))
+        .build()
+    {
+        Ok(c) => c,
+        Err(e) => {
+            return Err((
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(serde_json::json!({"error": format!("chat client build: {e}")})),
+            ));
+        }
+    };
+    let response_text = match chat_client
+        .post("http://localhost:3100/v1/chat")
+        .json(&chat_body)
+        .send()
+        .await
+    {
+        Ok(r) if r.status().is_success() => match r.json::<serde_json::Value>().await {
+            Ok(j) => j
+                .get("choices")
+                .and_then(|c| c.as_array())
+                .and_then(|a| a.first())
+                .and_then(|c| c.get("message"))
+                .and_then(|m| m.get("content"))
+                .and_then(|s| s.as_str())
+                .unwrap_or("")
+                .to_string(),
+            Err(e) => {
+                return Err((
+                    StatusCode::BAD_GATEWAY,
+                    Json(serde_json::json!({"error": format!("/v1/chat parse: {e}")})),
+                ));
+            }
+        },
+        Ok(r) => {
+            let status = r.status();
+            let body = r.text().await.unwrap_or_default();
+            return Err((
+                status,
+                Json(serde_json::json!({"error": "/v1/chat upstream error", "body": body})),
+            ));
+        }
+        Err(e) => {
+            return Err((
+                StatusCode::BAD_GATEWAY,
+                Json(serde_json::json!({"error": format!("/v1/chat send: {e}")})),
+            ));
+        }
+    };
+
+    Ok(Json(ExecuteResponse {
+        mode,
+        model,
+        task_class: req.task_class,
+        enriched_prompt_chars: enriched_chars,
+        enriched_prompt_preview: preview,
+        sources,
+        response: response_text,
+        latency_ms: t0.elapsed().as_millis() as u64,
+    }))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;