diff --git a/scripts/r102_harness_agent.py b/scripts/r102_harness_agent.py
index 1547036..b418102 100644
--- a/scripts/r102_harness_agent.py
+++ b/scripts/r102_harness_agent.py
@@ -229,10 +229,12 @@ def _result_text(result):
             return result, "", 0
         if isinstance(result, dict):
             return (str(result.get("stdout", "")), str(result.get("stderr", "")),
-                    int(result.get("returncode", result.get("exit_code", 0))))
+                    int(result.get("return_code", result.get("returncode",
+                                                               result.get("exit_code", 0)))))
         stdout = getattr(result, "stdout", "")
         stderr = getattr(result, "stderr", "")
-        code = getattr(result, "returncode", getattr(result, "exit_code", 0))
+        code = getattr(result, "return_code", getattr(
+            result, "returncode", getattr(result, "exit_code", 0)))
         return str(stdout or ""), str(stderr or ""), int(code or 0)
 
     @staticmethod
diff --git a/tests/r102_return_code.sh b/tests/r102_return_code.sh
new file mode 100755
index 0000000..3cf54d6
--- /dev/null
+++ b/tests/r102_return_code.sh
@@ -0,0 +1,77 @@
+#!/usr/bin/env bash
+set -euo pipefail
+cd "$(dirname "$0")/.."
+
+export PYTHONDONTWRITEBYTECODE=1
+python3 -B - <<'PY'
+import asyncio
+import importlib.util
+from pathlib import Path
+from types import SimpleNamespace
+import tempfile
+import sys
+
+root = Path.cwd()
+fake = Path(tempfile.mkdtemp(prefix="r102-return-code-"))
+for relative, body in {
+    "harbor/__init__.py": "",
+    "harbor/agents/__init__.py": "",
+    "harbor/agents/base.py": "class BaseAgent:\n    def __init__(self, *args, **kwargs):\n        pass\n",
+    "harbor/models/__init__.py": "",
+    "harbor/models/agent/__init__.py": "",
+    "harbor/models/agent/context.py": "class AgentContext: pass\n",
+}.items():
+    path = fake / relative
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_text(body)
+sys.path.insert(0, str(fake))
+spec = importlib.util.spec_from_file_location(
+    "r102_agent", root / "scripts" / "r102_harness_agent.py")
+agent_module = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(agent_module)
+
+def check(name, condition):
+    if not condition:
+        raise AssertionError(name)
+agent = agent_module.RelayHarnessAgent(
+    fake / "logs", row={"kind": "harness", "name": "fixture"})
+dict_fallbacks = [({"returncode": 2}, 2), ({"exit_code": 3}, 3), ({}, 0)]
+object_fallbacks = [(SimpleNamespace(returncode=2), 2),
+                   (SimpleNamespace(exit_code=3), 3), (SimpleNamespace(), 0)]
+for result, expected in dict_fallbacks:
+    check("dict return-code fallback", agent._result_text(result)[2] == expected)
+for result, expected in object_fallbacks:
+    check("object return-code fallback", agent._result_text(result)[2] == expected)
+check("dict return_code wins", agent._result_text({
+    "return_code": 7, "returncode": 8, "exit_code": 9})[2] == 7)
+check("object return_code wins", agent._result_text(SimpleNamespace(
+    return_code=7, returncode=8, exit_code=9))[2] == 7)
+check("stdout and stderr convert", agent._result_text({
+    "stdout": 123, "stderr": 456, "return_code": 0})[:2] == ("123", "456"))
+check("string result stays successful", agent._result_text("plain output") ==
+      ("plain output", "", 0))
+class Environment:
+    def __init__(self):
+        self.calls = []
+
+    async def exec(self, command, **kwargs):
+        self.calls.append((command, kwargs))
+        return {"stdout": "worker output", "stderr": "worker error", "return_code": 7}
+
+
+async def invoke_worker():
+    worker = agent_module.RelayHarnessAgent(
+        fake / "worker-logs",
+        row={"kind": "harness", "name": "fixture", "worker": {
+            "vendor": "codex", "model": "fixture", "effort": "high"}})
+    environment = Environment()
+    outcome = None
+    try:
+        outcome = await worker._invoke_role("worker", "work", environment, 0)
+    except RuntimeError as exc:
+        return outcome, str(exc), environment.calls
+    return outcome, "", environment.calls
+outcome, error, calls = asyncio.run(invoke_worker())
+check("worker return_code failure raises", outcome is None and
+      "worker invocation exited 7" in error and len(calls) == 1)
+PY