From 622651ec35a52eee90ba477287004b1e83f15604 Mon Sep 17 00:00:00 2001
From: Stephen Belanger <stephen.belanger@braintrustdata.com>
Date: Fri, 30 Oct 2026 18:43:48 +0800
Subject: [PATCH] Capture OpenCode model variants

---
 bt-daemon/src/translate/opencode.rs    | 9 ++++++++-
 bt-daemon/tests/opencode_translator.rs | 7 ++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/bt-daemon/src/translate/opencode.rs b/bt-daemon/src/translate/opencode.rs
index d4be4955..c487b0cf 100644
--- a/bt-daemon/src/translate/opencode.rs
+++ b/bt-daemon/src/translate/opencode.rs
@@ -289,6 +289,8 @@ struct MessageInfo {
     #[serde(default, rename = "modelID")]
     model_id: Option<String>,
     #[serde(default)]
+    variant: Option<String>,
+    #[serde(default)]
     time: Option<MessageTime>,
     #[serde(default)]
     tokens: Option<MessageTokens>,
@@ -987,6 +989,11 @@ impl OpenCodeTranslator {
         };
         let provider = info.provider_id.as_deref().unwrap_or("unknown");
         let model = info.model_id.as_deref().unwrap_or("unknown");
+        // Allowlist the selected OpenCode variant; do not copy arbitrary model options.
+        let mut metadata = json!({"model":model,"provider":provider,"message_id":mid});
+        if let Some(variant) = &info.variant {
+            metadata["variant"] = json!(variant);
+        }
         vec![SpanOp::Insert(SpanRow {
             span_id: ids::span_id(&self.daemon_session_id, &format!("llm:{sid}:{mid}")),
             root_span_id: state.effective_root_span_id.clone(),
@@ -1011,7 +1018,7 @@ impl OpenCodeTranslator {
                 .or(Some(ts_ms)),
             input: Some(Value::Array(input)),
             output: Some(Value::Array(vec![assistant])),
-            metadata: Some(json!({"model":model,"provider":provider,"message_id":mid})),
+            metadata: Some(metadata),
             metrics: Some(
                 json!({"prompt_tokens":prompt,"completion_tokens":completion,"tokens":prompt+completion+reasoning,"prompt_cached_tokens":cache_read,"prompt_cache_creation_tokens":cache_write,"reasoning_tokens":reasoning}),
             ),
diff --git a/bt-daemon/tests/opencode_translator.rs b/bt-daemon/tests/opencode_translator.rs
index 255399d1..6e4935f8 100644
--- a/bt-daemon/tests/opencode_translator.rs
+++ b/bt-daemon/tests/opencode_translator.rs
@@ -91,7 +91,7 @@ fn opencode_builds_turn_llm_tool_and_closes_the_session() {
         event(
             "message.updated",
             5,
-            json!({"properties":{"info":{"id":"m1","sessionID":"native","role":"assistant","providerID":"openai","modelID":"gpt-5","time":{"created":2,"completed":5},"tokens":{"input":5,"output":2,"reasoning":1,"cache":{"read":3,"write":4}}}}}),
+            json!({"properties":{"info":{"id":"m1","sessionID":"native","role":"assistant","providerID":"openai","modelID":"gpt-5","variant":"high","time":{"created":2,"completed":5},"tokens":{"input":5,"output":2,"reasoning":1,"cache":{"read":3,"write":4}}}}}),
         ),
         event(
             "tool.execute.after",
@@ -120,6 +120,7 @@ fn opencode_builds_turn_llm_tool_and_closes_the_session() {
         .values()
         .find(|r| r.span_type == SpanType::Llm)
         .unwrap();
+    assert_eq!(llm.metadata.as_ref().unwrap()["variant"], "high");
     assert_eq!(llm.metrics.as_ref().unwrap()["prompt_tokens"], 12);
     assert_eq!(llm.output.as_ref().unwrap()[0]["content"], "world");
     let tool = rows
@@ -260,6 +261,10 @@ fn opencode_idle_updates_a_resumable_session_root() {
         .count();
     assert_eq!(reopened_roots, 1);
     let rows = reduce(ops);
+    assert!(rows
+        .values()
+        .filter(|row| row.span_type == SpanType::Llm)
+        .all(|row| row.metadata.as_ref().unwrap().get("variant").is_none()));
     let root = rows.values().find(|row| row.name == "OpenCode").unwrap();
     assert_eq!(root.metadata.as_ref().unwrap()["total_turns"], 2);
     assert_eq!(root.end_ms, Some(13));