Split trace compare types into owned module

apps/elf-eval/src/app/trace_compare.rs

@@ -1,4 +1,5 @@
 mod analysis;
+mod types;
 
 use std::path::Path;
 
@@ -9,15 +10,15 @@ use uuid::Uuid;
 use crate::app::{
 	Args,
 	metrics::{self},
-	types::{
-		TraceCompareCandidateRow, TraceCompareChurn, TraceCompareGuardrails, TraceCompareOutput,
-		TraceComparePolicies, TraceComparePolicy, TraceCompareStageRow, TraceCompareSummary,
-		TraceCompareTrace, TraceCompareTraceRow, TraceCompareVariant,
-	},
 };
 use elf_config::Config;
 use elf_service::search::{self, TraceReplayContext};
 use elf_storage::db::Db;
+use types::{
+	TraceCompareCandidateRow, TraceCompareChurn, TraceCompareGuardrails, TraceCompareOutput,
+	TraceComparePolicies, TraceComparePolicy, TraceCompareStageRow, TraceCompareSummary,
+	TraceCompareTrace, TraceCompareTraceRow, TraceCompareVariant,
+};
 
 pub(super) async fn trace_compare(
 	config_a_path: &Path,

apps/elf-eval/src/app/trace_compare/analysis.rs

@@ -2,7 +2,7 @@ use std::collections::HashMap;
 
 use uuid::Uuid;
 
-use crate::app::types::{
+use crate::app::trace_compare::types::{
 	TraceCompareCandidateRow, TraceCompareChurn, TraceCompareGuardrails,
 	TraceCompareRegressionAttribution, TraceCompareStageDelta, TraceCompareStageRow,
 };
@@ -132,8 +132,8 @@ mod tests {
 	use time::OffsetDateTime;
 	use uuid::Uuid;
 
-	use crate::app::{
-		trace_compare::analysis,
+	use crate::app::trace_compare::{
+		analysis,
 		types::{
 			TraceCompareCandidateRow, TraceCompareChurn, TraceCompareGuardrails,
 			TraceCompareStageDelta, TraceCompareStageRow,

apps/elf-eval/src/app/trace_compare/types.rs

@@ -0,0 +1,202 @@
+use serde::Serialize;
+use serde_json::Value;
+use sqlx::FromRow;
+use time::OffsetDateTime;
+use uuid::Uuid;
+
+use elf_service::search::TraceReplayItem;
+
+#[derive(Debug, Serialize)]
+pub(in crate::app) struct TraceCompareOutput {
+	pub(super) policies: TraceComparePolicies,
+	pub(super) summary: TraceCompareSummary,
+	pub(super) traces: Vec<TraceCompareTrace>,
+}
+
+#[derive(Debug, Serialize)]
+pub(super) struct TraceComparePolicies {
+	pub(super) a: TraceComparePolicy,
+	pub(super) b: TraceComparePolicy,
+}
+
+#[derive(Debug, Serialize)]
+pub(super) struct TraceComparePolicy {
+	pub(super) config_path: String,
+	pub(super) policy_id: String,
+}
+
+#[derive(Debug, Serialize)]
+pub(super) struct TraceCompareSummary {
+	pub(super) trace_count: usize,
+	pub(super) avg_positional_churn_at_k: f64,
+	pub(super) avg_set_churn_at_k: f64,
+	pub(super) avg_a_retrieval_top3_retention: f64,
+	pub(super) avg_b_retrieval_top3_retention: f64,
+	pub(super) avg_retrieval_top3_retention_delta: f64,
+}
+
+#[derive(Debug, Serialize)]
+pub(super) struct TraceCompareTrace {
+	pub(super) trace_id: Uuid,
+	pub(super) query: String,
+	pub(super) candidate_count: u32,
+	pub(super) top_k: u32,
+	pub(super) created_at: String,
+	pub(super) a: TraceCompareVariant,
+	pub(super) b: TraceCompareVariant,
+	pub(super) churn: TraceCompareChurn,
+	pub(super) guardrails: TraceCompareGuardrails,
+	pub(super) stage_deltas: Vec<TraceCompareStageDelta>,
+	pub(super) regression_attribution: TraceCompareRegressionAttribution,
+}
+
+#[derive(Debug, Serialize)]
+pub(super) struct TraceCompareVariant {
+	pub(super) policy_id: String,
+	pub(super) items: Vec<TraceReplayItem>,
+}
+
+#[derive(Debug, Serialize)]
+pub(super) struct TraceCompareChurn {
+	pub(super) positional_churn_at_k: f64,
+	pub(super) set_churn_at_k: f64,
+}
+
+#[derive(Debug, Serialize)]
+pub(super) struct TraceCompareGuardrails {
+	pub(super) retrieval_top3_total: usize,
+	pub(super) a_retrieval_top3_retained: usize,
+	pub(super) a_retrieval_top3_retention: f64,
+	pub(super) b_retrieval_top3_retained: usize,
+	pub(super) b_retrieval_top3_retention: f64,
+	pub(super) retrieval_top3_retention_delta: f64,
+}
+
+#[derive(Debug, Serialize)]
+pub(super) struct TraceCompareStageDelta {
+	pub(super) stage_order: u32,
+	pub(super) stage_name: String,
+	pub(super) baseline_item_count: u32,
+	pub(super) a_item_count: u32,
+	pub(super) b_item_count: u32,
+	pub(super) item_count_delta: i64,
+	#[serde(skip_serializing_if = "Option::is_none")]
+	pub(super) baseline_stats: Option<Value>,
+}
+
+#[derive(Debug, Serialize)]
+pub(super) struct TraceCompareRegressionAttribution {
+	pub(super) primary_stage: String,
+	pub(super) evidence: String,
+}
+
+#[derive(FromRow)]
+pub(super) struct TraceCompareTraceRow {
+	pub(super) trace_id: Uuid,
+	pub(super) query: String,
+	pub(super) candidate_count: i32,
+	pub(super) top_k: i32,
+	pub(super) created_at: OffsetDateTime,
+}
+
+#[derive(FromRow)]
+pub(super) struct TraceCompareCandidateRow {
+	pub(super) candidate_snapshot: Value,
+	pub(super) note_id: Uuid,
+	pub(super) chunk_id: Uuid,
+	pub(super) chunk_index: i32,
+	pub(super) snippet: String,
+	pub(super) retrieval_rank: i32,
+	pub(super) rerank_score: f32,
+	pub(super) note_scope: String,
+	pub(super) note_importance: f32,
+	pub(super) note_updated_at: OffsetDateTime,
+	pub(super) note_hit_count: i64,
+	pub(super) note_last_hit_at: Option<OffsetDateTime>,
+}
+
+#[derive(FromRow)]
+pub(super) struct TraceCompareStageRow {
+	pub(super) stage_order: i32,
+	pub(super) stage_name: String,
+	pub(super) stage_payload: Value,
+	pub(super) item_count: i64,
+}
+
+#[cfg(test)]
+mod tests {
+	use serde_json::json;
+	use uuid::Uuid;
+
+	use crate::app::trace_compare::types::{
+		TraceCompareChurn, TraceCompareGuardrails, TraceCompareOutput, TraceComparePolicies,
+		TraceComparePolicy, TraceCompareRegressionAttribution, TraceCompareStageDelta,
+		TraceCompareSummary, TraceCompareTrace, TraceCompareVariant,
+	};
+
+	#[test]
+	fn trace_compare_output_serializes_nested_report_contract() {
+		let trace_id = Uuid::new_v4();
+		let output = TraceCompareOutput {
+			policies: TraceComparePolicies {
+				a: TraceComparePolicy {
+					config_path: "a.toml".to_string(),
+					policy_id: "policy-a".to_string(),
+				},
+				b: TraceComparePolicy {
+					config_path: "b.toml".to_string(),
+					policy_id: "policy-b".to_string(),
+				},
+			},
+			summary: TraceCompareSummary {
+				trace_count: 1,
+				avg_positional_churn_at_k: 0.25,
+				avg_set_churn_at_k: 0.5,
+				avg_a_retrieval_top3_retention: 1.0,
+				avg_b_retrieval_top3_retention: 0.5,
+				avg_retrieval_top3_retention_delta: -0.5,
+			},
+			traces: vec![TraceCompareTrace {
+				trace_id,
+				query: "find project context".to_string(),
+				candidate_count: 7,
+				top_k: 3,
+				created_at: "2026-01-01T00:00:00Z".to_string(),
+				a: TraceCompareVariant { policy_id: "policy-a".to_string(), items: Vec::new() },
+				b: TraceCompareVariant { policy_id: "policy-b".to_string(), items: Vec::new() },
+				churn: TraceCompareChurn { positional_churn_at_k: 0.25, set_churn_at_k: 0.5 },
+				guardrails: TraceCompareGuardrails {
+					retrieval_top3_total: 3,
+					a_retrieval_top3_retained: 3,
+					a_retrieval_top3_retention: 1.0,
+					b_retrieval_top3_retained: 2,
+					b_retrieval_top3_retention: 0.6667,
+					retrieval_top3_retention_delta: -0.3333,
+				},
+				stage_deltas: vec![TraceCompareStageDelta {
+					stage_order: 1,
+					stage_name: "selection.final".to_string(),
+					baseline_item_count: 3,
+					a_item_count: 3,
+					b_item_count: 2,
+					item_count_delta: -1,
+					baseline_stats: Some(json!({"selected": 3})),
+				}],
+				regression_attribution: TraceCompareRegressionAttribution {
+					primary_stage: "selection.final".to_string(),
+					evidence: "retention changed".to_string(),
+				},
+			}],
+		};
+		let value = serde_json::to_value(output).expect("Trace compare output serializes.");
+
+		assert_eq!(value["policies"]["a"]["policy_id"], "policy-a");
+		assert_eq!(value["summary"]["trace_count"], 1);
+		assert_eq!(value["traces"][0]["trace_id"], trace_id.to_string());
+		assert_eq!(value["traces"][0]["stage_deltas"][0]["baseline_stats"], json!({"selected": 3}));
+		assert_eq!(
+			value["traces"][0]["regression_attribution"]["primary_stage"],
+			"selection.final"
+		);
+	}
+}

apps/elf-eval/src/app/types.rs

@@ -1,11 +1,8 @@
 use serde::{Deserialize, Serialize};
-use serde_json::Value;
-use sqlx::FromRow;
-use time::OffsetDateTime;
 use uuid::Uuid;
 
 use crate::app::SearchMode;
-use elf_service::{RankingRequestOverride, SearchRequest, search::TraceReplayItem};
+use elf_service::{RankingRequestOverride, SearchRequest};
 
 #[derive(Debug, Deserialize)]
 pub(super) struct EvalDataset {
@@ -218,123 +215,6 @@ pub(super) struct QueryStabilityDelta {
 	pub(super) set_churn_at_k: f64,
 }
 
-#[derive(Debug, Serialize)]
-pub(super) struct TraceCompareOutput {
-	pub(super) policies: TraceComparePolicies,
-	pub(super) summary: TraceCompareSummary,
-	pub(super) traces: Vec<TraceCompareTrace>,
-}
-
-#[derive(Debug, Serialize)]
-pub(super) struct TraceComparePolicies {
-	pub(super) a: TraceComparePolicy,
-	pub(super) b: TraceComparePolicy,
-}
-
-#[derive(Debug, Serialize)]
-pub(super) struct TraceComparePolicy {
-	pub(super) config_path: String,
-	pub(super) policy_id: String,
-}
-
-#[derive(Debug, Serialize)]
-pub(super) struct TraceCompareSummary {
-	pub(super) trace_count: usize,
-	pub(super) avg_positional_churn_at_k: f64,
-	pub(super) avg_set_churn_at_k: f64,
-	pub(super) avg_a_retrieval_top3_retention: f64,
-	pub(super) avg_b_retrieval_top3_retention: f64,
-	pub(super) avg_retrieval_top3_retention_delta: f64,
-}
-
-#[derive(Debug, Serialize)]
-pub(super) struct TraceCompareTrace {
-	pub(super) trace_id: Uuid,
-	pub(super) query: String,
-	pub(super) candidate_count: u32,
-	pub(super) top_k: u32,
-	pub(super) created_at: String,
-	pub(super) a: TraceCompareVariant,
-	pub(super) b: TraceCompareVariant,
-	pub(super) churn: TraceCompareChurn,
-	pub(super) guardrails: TraceCompareGuardrails,
-	pub(super) stage_deltas: Vec<TraceCompareStageDelta>,
-	pub(super) regression_attribution: TraceCompareRegressionAttribution,
-}
-
-#[derive(Debug, Serialize)]
-pub(super) struct TraceCompareVariant {
-	pub(super) policy_id: String,
-	pub(super) items: Vec<TraceReplayItem>,
-}
-
-#[derive(Debug, Serialize)]
-pub(super) struct TraceCompareChurn {
-	pub(super) positional_churn_at_k: f64,
-	pub(super) set_churn_at_k: f64,
-}
-
-#[derive(Debug, Serialize)]
-pub(super) struct TraceCompareGuardrails {
-	pub(super) retrieval_top3_total: usize,
-	pub(super) a_retrieval_top3_retained: usize,
-	pub(super) a_retrieval_top3_retention: f64,
-	pub(super) b_retrieval_top3_retained: usize,
-	pub(super) b_retrieval_top3_retention: f64,
-	pub(super) retrieval_top3_retention_delta: f64,
-}
-
-#[derive(Debug, Serialize)]
-pub(super) struct TraceCompareStageDelta {
-	pub(super) stage_order: u32,
-	pub(super) stage_name: String,
-	pub(super) baseline_item_count: u32,
-	pub(super) a_item_count: u32,
-	pub(super) b_item_count: u32,
-	pub(super) item_count_delta: i64,
-	#[serde(skip_serializing_if = "Option::is_none")]
-	pub(super) baseline_stats: Option<Value>,
-}
-
-#[derive(Debug, Serialize)]
-pub(super) struct TraceCompareRegressionAttribution {
-	pub(super) primary_stage: String,
-	pub(super) evidence: String,
-}
-
-#[derive(FromRow)]
-pub(super) struct TraceCompareTraceRow {
-	pub(super) trace_id: Uuid,
-	pub(super) query: String,
-	pub(super) candidate_count: i32,
-	pub(super) top_k: i32,
-	pub(super) created_at: OffsetDateTime,
-}
-
-#[derive(FromRow)]
-pub(super) struct TraceCompareCandidateRow {
-	pub(super) candidate_snapshot: Value,
-	pub(super) note_id: Uuid,
-	pub(super) chunk_id: Uuid,
-	pub(super) chunk_index: i32,
-	pub(super) snippet: String,
-	pub(super) retrieval_rank: i32,
-	pub(super) rerank_score: f32,
-	pub(super) note_scope: String,
-	pub(super) note_importance: f32,
-	pub(super) note_updated_at: OffsetDateTime,
-	pub(super) note_hit_count: i64,
-	pub(super) note_last_hit_at: Option<OffsetDateTime>,
-}
-
-#[derive(FromRow)]
-pub(super) struct TraceCompareStageRow {
-	pub(super) stage_order: i32,
-	pub(super) stage_name: String,
-	pub(super) stage_payload: Value,
-	pub(super) item_count: i64,
-}
-
 pub(super) struct MergedQuery {
 	pub(super) id: String,
 	pub(super) query: String,