Add system-level test coverage for OpenCode and PiAgent sources

CLAUDE.md

@@ -38,7 +38,7 @@ cargo build --release
 cargo test
 ```
 
-Integration tests share `tests/support/` (env-isolated `TestEnv`, payload builders, in-process fake Langfuse). `tests/concurrency_test.rs` is the Track 2 race suite; tests `#[ignore]`d "red until fix-state-locking" are expected failures demonstrating the non-blocking-flock bug. `CODE_TRACE_SYNC_SEND=1` makes sends inline (no fork) for exact delivery assertions. The Track 1 container harness (real `claude` + stub model API + fake Langfuse) lives in `harness/` — see `harness/README.md`.
+Integration tests share `tests/support/` (env-isolated `TestEnv`, payload builders, in-process fake Langfuse). `tests/concurrency_test.rs` is the Track 2 race suite; tests `#[ignore]`d "red until fix-state-locking" are expected failures demonstrating the non-blocking-flock bug. `tests/source_system_test.rs` covers system-level OpenCode and PiAgent pipelines (stdin → binary → fake Langfuse), mirroring the Claude Code coverage in `cli_test.rs`/`concurrency_test.rs`. `CODE_TRACE_SYNC_SEND=1` makes sends inline (no fork) for exact delivery assertions. The Track 1 container harness (real `claude` + stub model API + fake Langfuse) lives in `harness/` — see `harness/README.md`.
 
 ## Adding a new source
 

src/turns.rs

@@ -75,6 +75,23 @@ pub fn build_turns(messages: Vec<Value>) -> Vec<Turn> {
             if !assistant_latest.contains_key(&mid) {
                 assistant_order.push(mid.clone());
             }
+            // Tool results for OpenCode/PiAgent are attached to the assistant
+            // message itself (message.tool_results) by the source normalizers,
+            // not delivered as separate user messages like Claude Code. Extract
+            // them here so emit.rs can populate tool-span outputs. Additive:
+            // Claude Code assistant messages never carry this field.
+            if let Some(trs) = msg
+                .get("message")
+                .and_then(|m| m.get("tool_results"))
+                .and_then(|v| v.as_array())
+            {
+                for tr in trs {
+                    if let Some(tid) = tr.get("tool_use_id").and_then(|v| v.as_str()) {
+                        let content = tr.get("content").cloned().unwrap_or(Value::Null);
+                        tool_results_by_id.insert(tid.to_string(), content);
+                    }
+                }
+            }
             assistant_latest.insert(mid, msg);
             continue;
         }