merge: integrate usage response models with service tier badges

Merge upstream PR #837, preserving its original commits and resolving the UsageModelDisplay layout conflict after #841. Cover response models alongside dynamic service-tier badges in detail tests.

crates/aether-admin/src/observability/usage.rs

@@ -1349,6 +1349,7 @@ fn admin_usage_active_request_json(
     if let Some(target_model) = item.target_model.as_ref() {
         value["target_model"] = json!(target_model);
     }
+    value["response_model"] = json!(item.provider_response_model());
     if let Some(reasoning_effort) = item.provider_reasoning_effort() {
         value["reasoning_effort"] = json!(reasoning_effort);
     }
@@ -1445,6 +1446,11 @@ pub fn admin_usage_record_json(
     let object = payload
         .as_object_mut()
         .expect("admin usage record payload should be an object");
+    // 大型 json! 宏接近 Rust 的递归展开上限，响应模型在宏展开后补入即可避免编译失败。
+    object.insert(
+        "response_model".to_string(),
+        json!(item.provider_response_model()),
+    );
     object.insert(
         "end_to_end_time_ms".to_string(),
         json!(admin_usage_metadata_u64(item, "end_to_end_time_ms")),
@@ -2842,6 +2848,32 @@ mod tests {
         assert_eq!(record["client_is_stream"], false);
     }
 
+    #[test]
+    fn admin_usage_payloads_expose_response_model_separately_from_mapping() {
+        let item = StoredRequestUsageAudit {
+            target_model: Some("provider-mapped-model".to_string()),
+            request_metadata: Some(json!({
+                "provider_response_model": "gpt-5.1"
+            })),
+            ..sample_usage("completed", Some(200), None)
+        };
+
+        let record = admin_usage_record_json(
+            &item,
+            &BTreeMap::new(),
+            &BTreeMap::new(),
+            false,
+            false,
+            None,
+        );
+        let active = admin_usage_active_request_json(&item, None, None, None);
+
+        for payload in [&record, &active] {
+            assert_eq!(payload["target_model"], "provider-mapped-model");
+            assert_eq!(payload["response_model"], "gpt-5.1");
+        }
+    }
+
     #[test]
     fn admin_usage_payloads_project_end_to_end_timings_from_metadata() {
         let item = StoredRequestUsageAudit {

crates/aether-data/adapters/postgres/src/usage/queries/list_recent_usage_audits_prefix.sql

@@ -183,6 +183,7 @@ SELECT
       OR NULLIF(BTRIM("usage".request_metadata->>'provider_reasoning_effort'), '') IS NOT NULL
       OR NULLIF(BTRIM("usage".request_metadata->>'provider_service_tier'), '') IS NOT NULL
       OR NULLIF(BTRIM("usage".request_metadata->>'provider_actual_service_tier'), '') IS NOT NULL
+      OR NULLIF(BTRIM("usage".request_metadata->>'provider_response_model'), '') IS NOT NULL
       OR ("usage".request_metadata->>'client_requested_stream') IN ('true', 'false')
       OR ("usage".request_metadata->>'upstream_is_stream') IN ('true', 'false')
       OR ("usage".request_metadata->>'websocket_mode') IN ('true', 'false')
@@ -208,6 +209,8 @@ SELECT
         NULLIF(BTRIM("usage".request_metadata->>'provider_service_tier'), ''),
         'provider_actual_service_tier',
         NULLIF(BTRIM("usage".request_metadata->>'provider_actual_service_tier'), ''),
+        'provider_response_model',
+        NULLIF(BTRIM("usage".request_metadata->>'provider_response_model'), ''),
         'client_requested_stream',
         CASE
           WHEN ("usage".request_metadata->>'client_requested_stream') IN ('true', 'false')

crates/aether-data/adapters/postgres/src/usage/queries/list_usage_audits_prefix.sql

@@ -183,6 +183,7 @@ SELECT
       OR NULLIF(BTRIM("usage".request_metadata->>'provider_reasoning_effort'), '') IS NOT NULL
       OR NULLIF(BTRIM("usage".request_metadata->>'provider_service_tier'), '') IS NOT NULL
       OR NULLIF(BTRIM("usage".request_metadata->>'provider_actual_service_tier'), '') IS NOT NULL
+      OR NULLIF(BTRIM("usage".request_metadata->>'provider_response_model'), '') IS NOT NULL
       OR ("usage".request_metadata->>'client_requested_stream') IN ('true', 'false')
       OR ("usage".request_metadata->>'upstream_is_stream') IN ('true', 'false')
       OR ("usage".request_metadata->>'websocket_mode') IN ('true', 'false')
@@ -208,6 +209,8 @@ SELECT
         NULLIF(BTRIM("usage".request_metadata->>'provider_service_tier'), ''),
         'provider_actual_service_tier',
         NULLIF(BTRIM("usage".request_metadata->>'provider_actual_service_tier'), ''),
+        'provider_response_model',
+        NULLIF(BTRIM("usage".request_metadata->>'provider_response_model'), ''),
         'client_requested_stream',
         CASE
           WHEN ("usage".request_metadata->>'client_requested_stream') IN ('true', 'false')

crates/aether-data/adapters/postgres/src/usage/tests.rs

@@ -3611,6 +3611,8 @@ fn usage_sql_uses_json_null_placeholders_for_usage_payload_columns() {
         assert!(sql.contains("request_metadata->>'provider_reasoning_effort'"));
         assert!(sql.contains("request_metadata->>'provider_service_tier'"));
         assert!(sql.contains("request_metadata->>'provider_actual_service_tier'"));
+        assert!(sql.contains("request_metadata->>'provider_response_model'"));
+        assert!(sql.contains("'provider_response_model'"));
         assert!(sql.contains("request_metadata->>'websocket_mode'"));
         assert!(sql.contains("'websocket_mode'"));
         assert!(sql.contains("AS client_family"));

crates/aether-data/contracts/src/repository/usage/metadata_policy.rs

@@ -8,9 +8,10 @@ use serde_json::{Map, Value};
 use crate::repository::candidates::sanitize_request_candidate_skip_reason;
 
 use super::{
-    LIVE_SESSION_METADATA_KEY, PLAN_USAGE_RESERVATION_DEFERRED_METADATA_KEY,
-    PROVIDER_ACTUAL_SERVICE_TIER_METADATA_KEY, PROVIDER_CACHE_TTL_MINUTES_METADATA_KEY,
-    PROVIDER_REASONING_EFFORT_METADATA_KEY, PROVIDER_SERVICE_TIER_METADATA_KEY,
+    normalize_provider_response_model, LIVE_SESSION_METADATA_KEY,
+    PLAN_USAGE_RESERVATION_DEFERRED_METADATA_KEY, PROVIDER_ACTUAL_SERVICE_TIER_METADATA_KEY,
+    PROVIDER_CACHE_TTL_MINUTES_METADATA_KEY, PROVIDER_REASONING_EFFORT_METADATA_KEY,
+    PROVIDER_RESPONSE_MODEL_METADATA_KEY, PROVIDER_SERVICE_TIER_METADATA_KEY,
     REALTIME_SESSION_METADATA_KEY, REQUESTED_REASONING_EFFORT_METADATA_KEY,
     ROUTING_CANDIDATE_SKIP_REASON_METADATA_KEY, ROUTING_FAILURE_DIAGNOSTIC_METADATA_KEY,
     USAGE_AVAILABLE_METADATA_KEY, USAGE_PRICING_AVAILABLE_METADATA_KEY,
@@ -94,6 +95,12 @@ pub fn sanitize_usage_request_metadata_object(source: &Map<String, Value>) -> Op
     ] {
         insert_known_string(source, &mut target, key, sanitize_service_tier);
     }
+    insert_known_string(
+        source,
+        &mut target,
+        PROVIDER_RESPONSE_MODEL_METADATA_KEY,
+        normalize_provider_response_model,
+    );
     insert_bounded_u64(
         source,
         &mut target,
@@ -1279,6 +1286,23 @@ mod tests {
         }
     }
 
+    #[test]
+    fn persistence_projection_keeps_bounded_response_model_only_as_a_string() {
+        let metadata = sanitize_usage_request_metadata(Some(json!({
+            "provider_response_model": "  GPT-5.1  "
+        })))
+        .expect("response model should remain");
+        assert_eq!(metadata["provider_response_model"], "GPT-5.1");
+        assert!(sanitize_usage_request_metadata(Some(json!({
+            "provider_response_model": 42
+        })))
+        .is_none());
+        assert!(sanitize_usage_request_metadata(Some(json!({
+            "provider_response_model": "x".repeat(257)
+        })))
+        .is_none());
+    }
+
     #[test]
     fn persistence_projection_keeps_only_bounded_settlement_facts() {
         let metadata = sanitize_usage_request_metadata(Some(json!({

crates/aether-data/contracts/src/repository/usage/mod.rs

@@ -15,11 +15,12 @@ pub use policy::*;
 pub use types::{
     canonical_usage_body_ref_for, extract_provider_actual_service_tier_from_response,
     extract_provider_cache_ttl_minutes_from_metadata, extract_provider_reasoning_effort_from_body,
-    extract_provider_service_tier_from_body, normalize_provider_service_tier, parse_usage_body_ref,
+    extract_provider_response_model_from_bodies, extract_provider_service_tier_from_body,
+    normalize_provider_response_model, normalize_provider_service_tier, parse_usage_body_ref,
     resolve_provider_cache_ttl_minutes, resolve_provider_service_tier_from_request_capture,
-    usage_body_ref, usage_request_metadata_client_family, ApiKeyLastUsedDelta,
-    ManagementTokenCounterDelta, PendingUsageCleanupSummary, ProviderApiKeyWindowUsageRequest,
-    ProxyNodeCounterDelta, StoredProviderApiKeyUsageSummary,
+    usage_body_capture_is_authoritative, usage_body_ref, usage_request_metadata_client_family,
+    ApiKeyLastUsedDelta, ManagementTokenCounterDelta, PendingUsageCleanupSummary,
+    ProviderApiKeyWindowUsageRequest, ProxyNodeCounterDelta, StoredProviderApiKeyUsageSummary,
     StoredProviderApiKeyWindowUsageSummary, StoredProviderUsageSummary, StoredProviderUsageWindow,
     StoredRequestUsageAudit, StoredUsageAuditAggregation, StoredUsageAuditSummary,
     StoredUsageBodyPayload, StoredUsageBreakdownSummaryRow, StoredUsageCacheAffinityHitSummary,
@@ -46,9 +47,9 @@ pub use types::{
     UsageTimeSeriesQuery, UsageWriteRepository, LIVE_SESSION_METADATA_KEY,
     PLAN_USAGE_RESERVATION_DEFERRED_METADATA_KEY, PROVIDER_ACTUAL_SERVICE_TIER_METADATA_KEY,
     PROVIDER_CACHE_TTL_MINUTES_METADATA_KEY, PROVIDER_REASONING_EFFORT_METADATA_KEY,
-    PROVIDER_SERVICE_TIER_METADATA_KEY, REALTIME_SESSION_METADATA_KEY,
-    REQUESTED_REASONING_EFFORT_METADATA_KEY, ROUTING_CANDIDATE_SKIP_REASON_METADATA_KEY,
-    ROUTING_FAILURE_DIAGNOSTIC_METADATA_KEY, USAGE_AVAILABLE_METADATA_KEY,
-    USAGE_PRICING_AVAILABLE_METADATA_KEY, WEBSOCKET_MODE_METADATA_KEY,
-    WEBSOCKET_TRANSPORT_METADATA_KEY,
+    PROVIDER_RESPONSE_MODEL_METADATA_KEY, PROVIDER_SERVICE_TIER_METADATA_KEY,
+    REALTIME_SESSION_METADATA_KEY, REQUESTED_REASONING_EFFORT_METADATA_KEY,
+    ROUTING_CANDIDATE_SKIP_REASON_METADATA_KEY, ROUTING_FAILURE_DIAGNOSTIC_METADATA_KEY,
+    USAGE_AVAILABLE_METADATA_KEY, USAGE_PRICING_AVAILABLE_METADATA_KEY,
+    WEBSOCKET_MODE_METADATA_KEY, WEBSOCKET_TRANSPORT_METADATA_KEY,
 };

crates/aether-data/contracts/src/repository/usage/types.rs

@@ -1,3 +1,4 @@
+use aether_ai_formats::normalize_api_format_alias;
 use async_trait::async_trait;
 use chrono::{DateTime, Utc};
 use serde_json::Value;
@@ -6,6 +7,7 @@ pub const PROVIDER_REASONING_EFFORT_METADATA_KEY: &str = "provider_reasoning_eff
 pub const REQUESTED_REASONING_EFFORT_METADATA_KEY: &str = "requested_reasoning_effort";
 pub const PROVIDER_SERVICE_TIER_METADATA_KEY: &str = "provider_service_tier";
 pub const PROVIDER_ACTUAL_SERVICE_TIER_METADATA_KEY: &str = "provider_actual_service_tier";
+pub const PROVIDER_RESPONSE_MODEL_METADATA_KEY: &str = "provider_response_model";
 pub const PROVIDER_CACHE_TTL_MINUTES_METADATA_KEY: &str = "provider_cache_ttl_minutes";
 pub const ROUTING_CANDIDATE_SKIP_REASON_METADATA_KEY: &str = "routing_candidate_skip_reason";
 pub const ROUTING_FAILURE_DIAGNOSTIC_METADATA_KEY: &str = "routing_failure_diagnostic";
@@ -119,6 +121,141 @@ pub fn normalize_provider_service_tier(value: &str) -> Option<String> {
     Some(value.to_ascii_lowercase())
 }
 
+/// 清洗模型名称，保留大小写，只去除首尾空白。
+pub fn normalize_provider_response_model(value: &str) -> Option<String> {
+    let value = value.trim();
+    if value.is_empty() || value.len() > 256 {
+        return None;
+    }
+    Some(value.to_string())
+}
+
+fn extract_model_at_paths(value: &Value, paths: &[&[&str]]) -> Option<String> {
+    paths.iter().find_map(|path| {
+        let value = path
+            .iter()
+            .try_fold(value, |current, key| current.as_object()?.get(*key))?;
+        value.as_str().and_then(normalize_provider_response_model)
+    })
+}
+
+fn response_model_paths(provider_api_format: Option<&str>) -> &'static [&'static [&'static str]] {
+    match normalize_api_format_alias(provider_api_format.unwrap_or_default()).as_str() {
+        "gemini:generate_content" => {
+            // Gemini 原生响应使用 modelVersion；部分网关会改写为 model。
+            &[&["modelVersion"], &["model_version"], &["model"]]
+        }
+        "gemini:embedding" => {
+            // Gemini Embedding 可能返回 model、modelVersion 或 Vertex 的 deployedModelId。
+            &[
+                &["model"],
+                &["modelVersion"],
+                &["model_version"],
+                &["deployedModelId"],
+                &["deployed_model_id"],
+            ]
+        }
+        "gemini:interactions" => {
+            // Interactions 请求既可能叫 model，也可能叫 agent；响应优先读取 model。
+            &[
+                &["model"],
+                &["modelVersion"],
+                &["model_version"],
+                &["agent"],
+            ]
+        }
+        _ => &[&["model"]],
+    }
+}
+
+fn extract_model_from_known_response_wrappers(
+    response_body: &Value,
+    paths: &[&[&str]],
+) -> Option<String> {
+    // 只展开协议中已知的 response/chunks 包装，避免在候选内容、工具参数等任意嵌套
+    // 对象中搜索同名字段，误把 role="model" 一类内容当成响应模型。
+    extract_model_at_paths(response_body, paths)
+        .or_else(|| {
+            response_body
+                .get("response")
+                .and_then(|response| extract_model_at_paths(response, paths))
+        })
+        .or_else(|| {
+            response_body
+                .get("chunks")
+                .and_then(Value::as_array)
+                .and_then(|chunks| {
+                    chunks.iter().rev().find_map(|chunk| {
+                        extract_model_at_paths(chunk, paths).or_else(|| {
+                            chunk
+                                .get("response")
+                                .and_then(|response| extract_model_at_paths(response, paths))
+                        })
+                    })
+                })
+        })
+        .or_else(|| {
+            response_body
+                .get("response")
+                .and_then(|response| response.get("chunks"))
+                .and_then(Value::as_array)
+                .and_then(|chunks| {
+                    chunks.iter().rev().find_map(|chunk| {
+                        extract_model_at_paths(chunk, paths).or_else(|| {
+                            chunk
+                                .get("response")
+                                .and_then(|response| extract_model_at_paths(response, paths))
+                        })
+                    })
+                })
+        })
+}
+
+fn extract_provider_model_from_response_body(
+    response_body: &Value,
+    provider_api_format: Option<&str>,
+) -> Option<String> {
+    extract_model_from_known_response_wrappers(
+        response_body,
+        response_model_paths(provider_api_format),
+    )
+}
+
+fn extract_provider_model_from_request_body(
+    request_body: &Value,
+    request_api_format: Option<&str>,
+) -> Option<String> {
+    let paths: &[&[&str]] =
+        match normalize_api_format_alias(request_api_format.unwrap_or_default()).as_str() {
+            "gemini:interactions" => &[&["model"], &["agent"]],
+            _ => &[&["model"]],
+        };
+    extract_model_at_paths(request_body, paths)
+}
+
+/// 只有请求体和响应体都可作为完整事实时，才计算响应模型，避免用截断内容猜测。
+pub fn extract_provider_response_model_from_bodies(
+    request_body: Option<&Value>,
+    request_body_state: Option<UsageBodyCaptureState>,
+    request_api_format: Option<&str>,
+    response_body: Option<&Value>,
+    response_body_state: Option<UsageBodyCaptureState>,
+    provider_api_format: Option<&str>,
+) -> Option<String> {
+    if !usage_body_capture_is_authoritative(request_body, request_body_state)
+        || !usage_body_capture_is_authoritative(response_body, response_body_state)
+    {
+        return None;
+    }
+
+    let request_model =
+        extract_provider_model_from_request_body(request_body?, request_api_format)?;
+    let response_model =
+        extract_provider_model_from_response_body(response_body?, provider_api_format)?;
+
+    (request_model != response_model).then_some(response_model)
+}
+
 /// Resolves a provider processing tier exclusively from the final upstream request.
 ///
 /// A complete captured body is authoritative, including when it contains no tier. The metadata
@@ -129,7 +266,7 @@ pub fn resolve_provider_service_tier_from_request_capture(
     provider_request_body_state: Option<UsageBodyCaptureState>,
     request_metadata: Option<&Value>,
 ) -> Option<String> {
-    if request_body_capture_is_authoritative(provider_request_body, provider_request_body_state) {
+    if usage_body_capture_is_authoritative(provider_request_body, provider_request_body_state) {
         return extract_provider_service_tier_from_body(provider_request_body);
     }
 
@@ -153,7 +290,7 @@ pub fn resolve_provider_service_tier_from_request_capture(
         .and_then(normalize_provider_service_tier)
 }
 
-fn request_body_capture_is_authoritative(
+pub fn usage_body_capture_is_authoritative(
     request_body: Option<&Value>,
     request_body_state: Option<UsageBodyCaptureState>,
 ) -> bool {
@@ -184,7 +321,7 @@ fn resolve_reasoning_effort_from_request_capture(
     request_metadata: Option<&Value>,
     metadata_key: &str,
 ) -> Option<String> {
-    if request_body_capture_is_authoritative(request_body, request_body_state) {
+    if usage_body_capture_is_authoritative(request_body, request_body_state) {
         return extract_provider_reasoning_effort_from_body(request_body);
     }
 
@@ -701,6 +838,11 @@ impl StoredRequestUsageAudit {
             })
     }
 
+    pub fn provider_response_model(&self) -> Option<String> {
+        self.request_metadata_string(PROVIDER_RESPONSE_MODEL_METADATA_KEY)
+            .and_then(normalize_provider_response_model)
+    }
+
     pub fn provider_cache_ttl_minutes(&self) -> Option<i64> {
         resolve_provider_cache_ttl_minutes(
             self.endpoint_api_format
@@ -2646,7 +2788,8 @@ fn parse_timestamp(value: i64, field_name: &str) -> Result<u64, crate::DataLayer
 mod tests {
     use super::{
         canonical_usage_body_ref_for, extract_provider_actual_service_tier_from_response,
-        extract_provider_service_tier_from_body, normalize_provider_reasoning_effort,
+        extract_provider_response_model_from_bodies, extract_provider_service_tier_from_body,
+        normalize_provider_reasoning_effort, normalize_provider_response_model,
         normalize_provider_service_tier, resolve_provider_cache_ttl_minutes, usage_body_ref,
         StoredRequestUsageAudit, UpsertUsageRecord, UsageBodyCaptureState, UsageBodyCaptureStorage,
         UsageBodyField, UsageProviderPerformanceQuery, REALTIME_SESSION_METADATA_KEY,
@@ -2672,6 +2815,122 @@ mod tests {
         }
     }
 
+    #[test]
+    fn response_model_requires_authoritative_different_top_level_models() {
+        let request = json!({"model": " gpt-5 "});
+        let response = json!({"model": " gpt-5.1 "});
+        assert_eq!(
+            extract_provider_response_model_from_bodies(
+                Some(&request),
+                Some(UsageBodyCaptureState::Inline),
+                Some("openai:chat"),
+                Some(&response),
+                Some(UsageBodyCaptureState::Inline),
+                Some("openai:chat"),
+            ),
+            Some("gpt-5.1".to_string())
+        );
+        assert_eq!(
+            extract_provider_response_model_from_bodies(
+                Some(&request),
+                Some(UsageBodyCaptureState::Inline),
+                Some("openai:responses"),
+                Some(&json!({"model": "gpt-5"})),
+                Some(UsageBodyCaptureState::Inline),
+                Some("openai:responses"),
+            ),
+            None
+        );
+        assert_eq!(
+            extract_provider_response_model_from_bodies(
+                Some(&request),
+                Some(UsageBodyCaptureState::Truncated),
+                Some("openai:chat"),
+                Some(&response),
+                Some(UsageBodyCaptureState::Inline),
+                Some("openai:chat"),
+            ),
+            None
+        );
+    }
+
+    #[test]
+    fn response_model_keeps_case_and_rejects_invalid_values() {
+        assert_eq!(
+            normalize_provider_response_model("  GPT-5.1  "),
+            Some("GPT-5.1".to_string())
+        );
+        assert_eq!(normalize_provider_response_model("  "), None);
+        assert_eq!(normalize_provider_response_model(&"x".repeat(257)), None);
+        assert_eq!(
+            extract_provider_response_model_from_bodies(
+                Some(&json!({"model": "gpt-5"})),
+                None,
+                Some("openai:chat"),
+                Some(&json!({"model": 42})),
+                None,
+                Some("openai:chat"),
+            ),
+            None
+        );
+    }
+
+    #[test]
+    fn response_model_uses_provider_format_specific_nested_paths() {
+        let request = json!({"model": "gemini-2.5-flash"});
+        let response = json!({
+            "response": {
+                "modelVersion": "gemini-2.5-flash-001",
+                "candidates": [{"content": {"role": "model"}}]
+            }
+        });
+        assert_eq!(
+            extract_provider_response_model_from_bodies(
+                Some(&request),
+                Some(UsageBodyCaptureState::Inline),
+                Some("gemini:generate_content"),
+                Some(&response),
+                Some(UsageBodyCaptureState::Inline),
+                Some("gemini:generate_content"),
+            ),
+            Some("gemini-2.5-flash-001".to_string())
+        );
+
+        let wrapped_chunks = json!({
+            "chunks": [
+                {"response": {"modelVersion": "gemini-old"}},
+                {"response": {"modelVersion": "gemini-final"}}
+            ]
+        });
+        assert_eq!(
+            extract_provider_response_model_from_bodies(
+                Some(&request),
+                Some(UsageBodyCaptureState::Inline),
+                Some("gemini:generate_content"),
+                Some(&wrapped_chunks),
+                Some(UsageBodyCaptureState::Inline),
+                Some("gemini:generate_content"),
+            ),
+            Some("gemini-final".to_string())
+        );
+
+        let ambiguous = json!({
+            "metadata": {"model": "do-not-use"},
+            "candidates": [{"content": {"role": "model"}}]
+        });
+        assert_eq!(
+            extract_provider_response_model_from_bodies(
+                Some(&request),
+                Some(UsageBodyCaptureState::Inline),
+                Some("gemini:generate_content"),
+                Some(&ambiguous),
+                Some(UsageBodyCaptureState::Inline),
+                Some("gemini:generate_content"),
+            ),
+            None
+        );
+    }
+
     #[test]
     fn provider_fact_normalization_preserves_non_ascii_case_and_byte_count() {
         for normalize in [

crates/aether-usage/runtime/src/event_wire.rs

@@ -15,9 +15,9 @@ use super::{BorrowedUsageEventEnvelope, UsageEvent, UsageEventData, USAGE_EVENT_
 use crate::body_capture::mark_usage_event_capture_truncated;
 use crate::request_metadata::{
     attach_client_request_body_metadata, attach_provider_request_body_metadata,
-    attach_provider_response_body_metadata, clear_client_request_body_metadata,
-    clear_provider_request_body_metadata, request_body_derived_facts_action,
-    RequestBodyDerivedFactsAction,
+    attach_provider_response_body_metadata, attach_provider_response_model_metadata,
+    clear_client_request_body_metadata, clear_provider_request_body_metadata,
+    request_body_derived_facts_action, RequestBodyDerivedFactsAction,
 };
 
 const DIAGNOSTIC_FIELDS: [&str; 8] = [
@@ -238,6 +238,15 @@ impl WireOverrides {
             RequestBodyDerivedFactsAction::Clear | RequestBodyDerivedFactsAction::Preserve => {}
         }
         metadata = attach_provider_response_body_metadata(metadata, data.response_body.as_ref());
+        metadata = attach_provider_response_model_metadata(
+            metadata,
+            request_body,
+            data.request_body_state,
+            data.api_format.as_deref(),
+            data.response_body.as_ref(),
+            data.response_body_state,
+            data.endpoint_api_format.as_deref(),
+        );
         // Billing reads raw-body TTL before metadata regardless of capture state.
         // Preserve that precedence independently of reasoning and tier authority.
         if let Some(cache_ttl) = body_cache_ttl {

crates/aether-usage/runtime/src/record.rs

@@ -5,9 +5,9 @@ use aether_data_contracts::DataLayerError;
 
 use crate::request_metadata::{
     attach_client_request_body_metadata, attach_provider_request_body_metadata,
-    clear_client_request_body_metadata, clear_provider_request_body_metadata,
-    request_body_derived_facts_action, sanitize_usage_request_metadata,
-    RequestBodyDerivedFactsAction,
+    attach_provider_response_model_metadata, clear_client_request_body_metadata,
+    clear_provider_request_body_metadata, request_body_derived_facts_action,
+    sanitize_usage_request_metadata, RequestBodyDerivedFactsAction,
 };
 use crate::{UsageEvent, UsageEventType};
 
@@ -85,6 +85,16 @@ pub fn build_upsert_usage_record_from_event(
         }
         RequestBodyDerivedFactsAction::Preserve => {}
     }
+    // 响应模型必须在 body 被裁剪前从客户端请求体和上游响应体共同派生；缺少权威 body 时保留已派生事实。
+    data.request_metadata = attach_provider_response_model_metadata(
+        data.request_metadata,
+        data.request_body.as_ref(),
+        data.request_body_state,
+        data.api_format.as_deref(),
+        data.response_body.as_ref(),
+        data.response_body_state,
+        data.endpoint_api_format.as_deref(),
+    );
     let now_unix_secs = event.timestamp_ms / 1_000;
 
     Ok(UpsertUsageRecord {

crates/aether-usage/runtime/src/request_metadata.rs

@@ -1,13 +1,15 @@
 use aether_contracts::ExecutionPlan;
 use aether_data_contracts::repository::usage::{
     extract_provider_actual_service_tier_from_response,
-    extract_provider_reasoning_effort_from_body, extract_provider_service_tier_from_body,
-    normalize_provider_service_tier, resolve_provider_cache_ttl_minutes,
+    extract_provider_reasoning_effort_from_body, extract_provider_response_model_from_bodies,
+    extract_provider_service_tier_from_body, normalize_provider_service_tier,
+    resolve_provider_cache_ttl_minutes,
     sanitize_usage_request_metadata as project_usage_request_metadata,
     sanitize_usage_request_metadata_object as project_usage_request_metadata_object,
     sanitize_usage_request_metadata_ref as project_usage_request_metadata_ref,
-    UsageBodyCaptureState, PROVIDER_ACTUAL_SERVICE_TIER_METADATA_KEY,
-    PROVIDER_CACHE_TTL_MINUTES_METADATA_KEY, PROVIDER_REASONING_EFFORT_METADATA_KEY,
+    usage_body_capture_is_authoritative, UsageBodyCaptureState,
+    PROVIDER_ACTUAL_SERVICE_TIER_METADATA_KEY, PROVIDER_CACHE_TTL_MINUTES_METADATA_KEY,
+    PROVIDER_REASONING_EFFORT_METADATA_KEY, PROVIDER_RESPONSE_MODEL_METADATA_KEY,
     PROVIDER_SERVICE_TIER_METADATA_KEY, REQUESTED_REASONING_EFFORT_METADATA_KEY,
 };
 use serde_json::{Map, Value};
@@ -249,6 +251,83 @@ pub(crate) fn attach_provider_response_body_metadata(
     attach_provider_actual_service_tier_metadata(metadata, actual_service_tier.as_deref())
 }
 
+pub(crate) fn attach_provider_response_model_metadata(
+    metadata: Option<Value>,
+    request_body: Option<&Value>,
+    request_body_state: Option<UsageBodyCaptureState>,
+    request_api_format: Option<&str>,
+    response_body: Option<&Value>,
+    response_body_state: Option<UsageBodyCaptureState>,
+    provider_api_format: Option<&str>,
+) -> Option<Value> {
+    let both_bodies_are_authoritative =
+        usage_body_capture_is_authoritative(request_body, request_body_state)
+            && usage_body_capture_is_authoritative(response_body, response_body_state);
+    let response_model = extract_provider_response_model_from_bodies(
+        request_body,
+        request_body_state,
+        request_api_format,
+        response_body,
+        response_body_state,
+        provider_api_format,
+    );
+    if !both_bodies_are_authoritative && response_model.is_none() {
+        return metadata;
+    }
+
+    let mut object = match metadata {
+        Some(Value::Object(object)) => object,
+        _ => Map::new(),
+    };
+    // 完整终态 body 是最终候选的权威事实；相同、无效或缺失模型都要清除旧候选值。
+    if both_bodies_are_authoritative {
+        object.remove(PROVIDER_RESPONSE_MODEL_METADATA_KEY);
+    }
+    if let Some(response_model) = response_model {
+        object.insert(
+            PROVIDER_RESPONSE_MODEL_METADATA_KEY.to_string(),
+            Value::String(response_model),
+        );
+    }
+    (!object.is_empty()).then_some(Value::Object(object))
+}
+
+/// 终态候选无法完成比较时，显式清除旧响应模型，避免重试/故障转移残留。
+pub(crate) fn refresh_provider_response_model_metadata(
+    metadata: Option<Value>,
+    request_body: Option<&Value>,
+    request_body_state: Option<UsageBodyCaptureState>,
+    request_api_format: Option<&str>,
+    response_body: Option<&Value>,
+    response_body_state: Option<UsageBodyCaptureState>,
+    provider_api_format: Option<&str>,
+) -> Option<Value> {
+    let mut object = match metadata {
+        Some(Value::Object(object)) => object,
+        _ => Map::new(),
+    };
+    object.remove(PROVIDER_RESPONSE_MODEL_METADATA_KEY);
+
+    if usage_body_capture_is_authoritative(request_body, request_body_state)
+        && usage_body_capture_is_authoritative(response_body, response_body_state)
+    {
+        if let Some(response_model) = extract_provider_response_model_from_bodies(
+            request_body,
+            request_body_state,
+            request_api_format,
+            response_body,
+            response_body_state,
+            provider_api_format,
+        ) {
+            object.insert(
+                PROVIDER_RESPONSE_MODEL_METADATA_KEY.to_string(),
+                Value::String(response_model),
+            );
+        }
+    }
+    (!object.is_empty()).then_some(Value::Object(object))
+}
+
 /// Refreshes the response-derived tier for a terminal snapshot. Complete response objects are
 /// authoritative even when they contain no tier (which clears a stale candidate value). Capture
 /// placeholders/absent bodies are not authoritative, so a terminal summary already present in
@@ -312,6 +391,7 @@ pub(crate) fn attach_provider_actual_service_tier_metadata(
 #[cfg(test)]
 mod tests {
     use aether_contracts::{ExecutionPlan, RequestBody};
+    use aether_data_contracts::repository::usage::UsageBodyCaptureState;
     use serde_json::{json, Value};
     use std::collections::BTreeMap;
 
@@ -323,8 +403,9 @@ mod tests {
     use super::{
         attach_client_request_body_metadata, attach_provider_actual_service_tier_metadata,
         attach_provider_request_body_metadata, attach_provider_response_body_metadata,
-        build_usage_request_metadata_seed, merge_usage_request_metadata,
-        merge_usage_request_metadata_owned, refresh_provider_response_body_metadata,
+        attach_provider_response_model_metadata, build_usage_request_metadata_seed,
+        merge_usage_request_metadata, merge_usage_request_metadata_owned,
+        refresh_provider_response_body_metadata, refresh_provider_response_model_metadata,
         retain_first_byte_request_metadata, sanitize_usage_request_metadata,
         sanitize_usage_request_metadata_ref,
     };
@@ -802,6 +883,44 @@ mod tests {
         );
     }
 
+    #[test]
+    fn response_model_metadata_is_independent_from_mapping_and_clears_stale_values() {
+        let metadata = attach_provider_response_model_metadata(
+            Some(json!({"provider_response_model": "old-model", "trace_id": "trace-1"})),
+            Some(&json!({"model": "gpt-5"})),
+            Some(UsageBodyCaptureState::Inline),
+            Some("openai:chat"),
+            Some(&json!({"model": "gpt-5.1"})),
+            Some(UsageBodyCaptureState::Inline),
+            Some("openai:chat"),
+        )
+        .expect("response model should be attached");
+        assert_eq!(metadata["provider_response_model"], "gpt-5.1");
+        assert_eq!(metadata["trace_id"], "trace-1");
+
+        let metadata = refresh_provider_response_model_metadata(
+            Some(json!({"provider_response_model": "gpt-5.1"})),
+            Some(&json!({"model": "gpt-5"})),
+            Some(UsageBodyCaptureState::Inline),
+            Some("openai:chat"),
+            Some(&json!({"model": "gpt-5"})),
+            Some(UsageBodyCaptureState::Inline),
+            Some("openai:chat"),
+        );
+        assert!(metadata.is_none());
+
+        let metadata = refresh_provider_response_model_metadata(
+            Some(json!({"provider_response_model": "gpt-5.1"})),
+            None,
+            Some(UsageBodyCaptureState::Disabled),
+            Some("openai:chat"),
+            Some(&json!({"model": "gpt-5.2"})),
+            Some(UsageBodyCaptureState::Inline),
+            Some("openai:chat"),
+        );
+        assert!(metadata.is_none());
+    }
+
     #[test]
     fn terminal_response_refresh_replaces_stale_actual_tier() {
         let metadata = refresh_provider_response_body_metadata(

crates/aether-usage/runtime/src/runtime.rs

@@ -21,9 +21,10 @@ use crate::executor::spawn_on_usage_background_runtime;
 use crate::queue::is_permanent_enqueue_error;
 use crate::request_metadata::{
     attach_client_request_body_metadata, attach_provider_request_body_metadata,
-    attach_provider_response_body_metadata, clear_client_request_body_metadata,
-    clear_provider_request_body_metadata, request_body_derived_facts_action,
-    retain_first_byte_request_metadata, RequestBodyDerivedFactsAction,
+    attach_provider_response_body_metadata, attach_provider_response_model_metadata,
+    clear_client_request_body_metadata, clear_provider_request_body_metadata,
+    request_body_derived_facts_action, retain_first_byte_request_metadata,
+    RequestBodyDerivedFactsAction,
 };
 use crate::settlement::{
     reconcile_usage_policy_cost_for_event_with_result, settle_usage_with_reconciled_cost,
@@ -5297,8 +5298,17 @@ fn preserve_request_facts_with_legacy_missing(
 
 fn preserve_provider_response_facts(event: &mut UsageEvent) {
     let metadata = event.data.request_metadata.take();
-    event.data.request_metadata =
+    let metadata =
         attach_provider_response_body_metadata(metadata, event.data.response_body.as_ref());
+    event.data.request_metadata = attach_provider_response_model_metadata(
+        metadata,
+        event.data.request_body.as_ref(),
+        event.data.request_body_state,
+        event.data.api_format.as_deref(),
+        event.data.response_body.as_ref(),
+        event.data.response_body_state,
+        event.data.endpoint_api_format.as_deref(),
+    );
 }
 
 impl UsageQueueHealthSnapshot {

crates/aether-usage/runtime/src/write.rs

@@ -17,9 +17,10 @@ use crate::body_capture::{
 };
 use crate::request_metadata::{
     attach_client_request_body_metadata, attach_provider_actual_service_tier_metadata,
-    attach_provider_request_body_metadata, build_usage_request_metadata_seed,
-    merge_usage_request_metadata, merge_usage_request_metadata_owned,
-    refresh_provider_response_body_metadata, sanitize_usage_request_metadata,
+    attach_provider_request_body_metadata, attach_provider_response_model_metadata,
+    build_usage_request_metadata_seed, merge_usage_request_metadata,
+    merge_usage_request_metadata_owned, refresh_provider_response_body_metadata,
+    refresh_provider_response_model_metadata, sanitize_usage_request_metadata,
     sanitize_usage_request_metadata_ref,
 };
 use crate::{
@@ -724,6 +725,15 @@ fn build_terminal_usage_event_from_seed_impl(
         Some(model.as_str()),
         provider_request.as_ref(),
     );
+    let request_metadata = attach_provider_response_model_metadata(
+        request_metadata,
+        request_body.as_ref(),
+        body_states.request_body_state,
+        Some(client_contract.as_str()),
+        provider_response.as_ref(),
+        body_states.response_body_state,
+        Some(provider_contract.as_str()),
+    );
 
     let mut data = UsageEventData {
         user_id,
@@ -1047,6 +1057,15 @@ pub fn build_sync_terminal_usage_seed(
         context_seed.request_metadata,
         provider_response_full.as_ref(),
     );
+    let request_metadata = refresh_provider_response_model_metadata(
+        request_metadata,
+        context_seed.request_body.as_ref(),
+        context_seed.body_states.request_body_state,
+        Some(context_seed.client_contract.as_str()),
+        provider_response_full.as_ref(),
+        provider_response_body_state,
+        Some(context_seed.provider_contract.as_str()),
+    );
 
     TerminalUsageSeed {
         terminal_state,
@@ -1225,6 +1244,15 @@ pub fn build_stream_terminal_usage_seed(
         context_seed.request_metadata,
         provider_response_full.as_ref(),
     );
+    let request_metadata = refresh_provider_response_model_metadata(
+        request_metadata,
+        context_seed.request_body.as_ref(),
+        context_seed.body_states.request_body_state,
+        Some(context_seed.client_contract.as_str()),
+        provider_response_full.as_ref(),
+        provider_response_body_state,
+        Some(context_seed.provider_contract.as_str()),
+    );
     // The parser's terminal summary is authoritative when a response body is truncated or the
     // body and summary disagree; attach it after the body refresh so it wins.
     let request_metadata = attach_provider_actual_service_tier_metadata(