feat: add router-less cross-family reviewer CLI (cross_review.py)

Re-homes the archived orchestrator repo's GPT-4.1 cross_reviewer as a
direct OpenAI SDK CLI: verbatim system prompt, same model id, ported
3-attempt exponential-backoff retry. Reads OPENAI_API_KEY from the
environment or the gitignored repo-root .env. Lazy openai import so
--help works without the package.

cross_review.py

@@ -0,0 +1,139 @@
+#!/usr/bin/env python3
+"""cross_review.py — Sea Haven cross-family (GPT-4.1) review CLI.
+
+Re-homed from the archived Sea-Haven-Industries/orchestrator repo's
+`cross_reviewer` agent. Router-less: one direct OpenAI SDK call, no langchain,
+no routing logic. This is the mandatory cross-family reviewer for IAM/policy
+and Lambda-handler-signature changes, and the reasoning backend for the
+sh-plan-review / sh-security-audit / sh-build-review gates.
+
+Usage:
+    python3 cross_review.py "Review this diff for breaking changes: <diff>"
+
+Auth: reads OPENAI_API_KEY from the environment, falling back to the
+gitignored .env at the repo root. Never prints the key.
+"""
+
+import argparse
+import os
+import random
+import sys
+import time
+
+# Model ID — single source of truth (ported from orchestrator/models.py).
+DEFAULT_MODEL = "gpt-4.1"
+TEMPERATURE = 0.2
+MAX_ATTEMPTS = 3
+
+# System prompt ported verbatim from the orchestrator's cross_reviewer agent
+# (orchestrator/agents.py, CROSS_REVIEWER_PROMPT).
+CROSS_REVIEWER_PROMPT = """You are a cross-family code review agent. You provide an independent review perspective.
+Review the provided code for bugs, security issues, and improvements.
+Categorize findings as BLOCK, FIX, or NIT. Be concise.
+Focus on issues that might be missed by the primary development team."""
+
+
+def load_api_key() -> str:
+    """OPENAI_API_KEY from the environment, else hand-parsed from repo-root .env."""
+    key = os.environ.get("OPENAI_API_KEY")
+    if key:
+        return key
+    env_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), ".env")
+    try:
+        with open(env_path, encoding="utf-8") as f:
+            for line in f:
+                line = line.strip()
+                if not line or line.startswith("#") or "=" not in line:
+                    continue
+                name, _, value = line.partition("=")
+                if name.strip() == "OPENAI_API_KEY":
+                    return value.strip().strip("'\"")
+    except OSError:
+        pass
+    return ""
+
+
+def run_review(task: str, model: str, api_key: str) -> str:
+    """One review call with retries on transient API errors (3 attempts,
+    exponential backoff with jitter — ported from orchestrator/models.py
+    with_retries)."""
+    # Lazy import so --help works without the openai package installed.
+    import openai
+
+    retriable = (
+        openai.APIConnectionError,
+        openai.RateLimitError,
+        openai.InternalServerError,
+    )
+    client = openai.OpenAI(api_key=api_key)
+    for attempt in range(1, MAX_ATTEMPTS + 1):
+        try:
+            response = client.chat.completions.create(
+                model=model,
+                temperature=TEMPERATURE,
+                messages=[
+                    {"role": "system", "content": CROSS_REVIEWER_PROMPT},
+                    {"role": "user", "content": task},
+                ],
+            )
+            content = response.choices[0].message.content
+            if not content:
+                raise RuntimeError("model returned an empty review")
+            return content
+        except retriable as exc:
+            if attempt == MAX_ATTEMPTS:
+                raise
+            delay = (2 ** (attempt - 1)) + random.uniform(0, 1)
+            print(
+                f"cross_review: transient API error ({type(exc).__name__}), "
+                f"retrying in {delay:.1f}s (attempt {attempt}/{MAX_ATTEMPTS})",
+                file=sys.stderr,
+            )
+            time.sleep(delay)
+    raise RuntimeError("unreachable")
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(
+        description=(
+            "Cross-family GPT-4.1 review (direct OpenAI SDK, no router). "
+            "Mandatory for IAM/policy and Lambda-handler-signature changes."
+        )
+    )
+    parser.add_argument("task", help="review task: a diff, change description, or plan")
+    parser.add_argument(
+        "--model",
+        default=DEFAULT_MODEL,
+        help=f"OpenAI model id (default: {DEFAULT_MODEL})",
+    )
+    args = parser.parse_args()
+
+    api_key = load_api_key()
+    if not api_key:
+        print(
+            "cross_review: OPENAI_API_KEY not set and not found in repo-root .env",
+            file=sys.stderr,
+        )
+        return 2
+
+    try:
+        review = run_review(args.task, args.model, api_key)
+    except ImportError:
+        print(
+            "cross_review: the 'openai' package is not installed "
+            "(pip install -r requirements.txt)",
+            file=sys.stderr,
+        )
+        return 2
+    except Exception as exc:  # noqa: BLE001 — CLI boundary: report and exit nonzero
+        print(
+            f"cross_review: review failed: {type(exc).__name__}: {exc}", file=sys.stderr
+        )
+        return 1
+
+    print(review)
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())

requirements.txt

@@ -1,5 +1,6 @@
-# Path B headless agentic runner (run_headless.py). Scanners (semgrep, gitleaks,
+# Headless agentic runner (run_headless.py). Scanners (semgrep, gitleaks,
 # checkov, cfn-lint, pip-audit) and npm are external binaries, installed separately
-# (see README). The optional cross-model hook (ENABLE_XMODEL_HOOK=1) additionally
-# needs langchain-openai, intentionally not pinned here since it is off by default.
+# (see README).
 claude-agent-sdk
+# Cross-family reviewer CLI (cross_review.py) — direct OpenAI SDK, no langchain.
+openai