feat(agents): Harden the LLM call path against relay failure modes

scripts/relay_stream_smoke.py

@@ -0,0 +1,63 @@
+"""Smoke: does the relay accept stream=True + stream_options include_usage?
+
+This is THE load-bearing assumption of the audit-hardening change: if the
+relay 400s on stream_options (some OpenAI-compatible gateways do), every
+production call would fail over to Anthropic. One tiny real call settles it.
+Cost: a few hundred tokens on gpt-5.5.
+"""
+import os
+import sys
+
+# Load .env the same way the app does (no external deps needed).
+for line in open("/home/yebo/quant-agent/.env"):
+    line = line.strip()
+    if line.startswith("export "):
+        line = line[len("export "):]
+    if line and not line.startswith("#") and "=" in line:
+        k, _, v = line.partition("=")
+        os.environ.setdefault(k.strip(), v.strip().strip('"').strip("'"))
+
+from openai import OpenAI
+
+base_url = os.environ.get("OPENAI_BASE_URL") or None
+print(f"base_url: {base_url or 'api.openai.com (default)'}")
+client = OpenAI(api_key=os.environ["OPENAI_API_KEY"], base_url=base_url,
+                timeout=60.0, max_retries=0)
+
+stream = client.chat.completions.create(
+    model="gpt-5.5",
+    max_completion_tokens=512,
+    messages=[
+        {"role": "system", "content": "You are a smoke test."},
+        {"role": "user", "content": "Reply with exactly: OK"},
+    ],
+    stream=True,
+    stream_options={"include_usage": True},
+)
+
+parts, finish_reason, usage, n_chunks = [], None, None, 0
+for chunk in stream:
+    n_chunks += 1
+    if getattr(chunk, "usage", None) is not None:
+        usage = chunk.usage
+    choices = getattr(chunk, "choices", None) or []
+    if not choices:
+        continue
+    delta = getattr(choices[0], "delta", None)
+    piece = getattr(delta, "content", None) if delta is not None else None
+    if piece:
+        parts.append(piece)
+    fr = getattr(choices[0], "finish_reason", None)
+    if isinstance(fr, str):
+        finish_reason = fr
+
+content = "".join(parts)
+print(f"chunks: {n_chunks}")
+print(f"content: {content!r}")
+print(f"finish_reason: {finish_reason!r}")
+print(f"usage: {usage!r}")
+
+ok = bool(content) and finish_reason == "stop" and usage is not None
+print("RESULT:", "PASS — relay supports streaming + include_usage" if ok else
+      "PARTIAL — see fields above (usage None means the estimate fallback will engage)")
+sys.exit(0 if content and finish_reason else 1)