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AI-Native Software Development: How to Build a PR Review Assistant with Regolo Instead of Another Generic Copilot

The next phase of AI in software development is workflow-native, not chat-tab-native. Claude 4 was launched with a strong emphasis on coding and agent workflows, which reflects where engineering teams are spending real budget: code review, test generation, incident support, and repository-aware assistance.

For CTOs, the opportunity is process redesign. For developers, the opportunity is to place AI exactly where engineering work already happens: pull requests, diffs, CI logs, migration plans, and runbooks. Regolo’s chat-completions endpoint and live model catalog are enough to build a practical first version without introducing another closed orchestration layer.

Key concepts

The first concept is artifact-first assistance. Good engineering assistants do not start from general chat. They start from a diff, a failed test, a stack trace, or a deployment checklist.

The second concept is bounded outputs. Ask the model for review comments, risk level, missing tests, and rollout notes in a fixed structure. That makes the tool more useful for teams and easier to evaluate over time.

The third concept is change management. A PR review assistant creates value only when it reduces reviewer load without flooding the team with low-signal comments. That means you should optimize for precision before coverage.

Procedure and runnable code

A strong use case here is an ML platform team that ships model-serving changes every week. Reviewers are overloaded, and many PRs repeat the same classes of mistakes: missing backfill plans, silent schema changes, unbounded retries, and missing rollback notes.

The script below reads a local git diff, sends it to a Regolo chat model, and returns a structured review in Markdown. It is runnable with a normal Git repo, requests, and a Regolo API key. The Regolo docs show the exact chat-completions endpoint and the model-discovery endpoint used here.

# pr_review_assistant.py
import os
import json
import subprocess
from pathlib import Path
import requests
from typing import Any, Dict, List


def load_local_env(env_path: Path) -> None:
    if not env_path.exists():
        return

    for raw_line in env_path.read_text(encoding="utf-8").splitlines():
        line = raw_line.strip()
        if not line or line.startswith("#") or "=" not in line:
            continue

        key, value = line.split("=", 1)
        key = key.strip()
        value = value.strip().strip('"').strip("'")
        if key and key not in os.environ:
            os.environ[key] = value


load_local_env(Path(__file__).with_name(".env"))

API_KEY = os.getenv("REGOLO_API_KEY")
if not API_KEY:
    raise RuntimeError("REGOLO_API_KEY non trovato: definire REGOLO_API_KEY nel file .env o nelle variabili di ambiente")

BASE_URL = os.getenv("REGOLO_BASE_URL", "https://api.regolo.ai")

ENGINEERING_CHECKLIST = """
Review this PR with focus on:
1. correctness
2. security and secrets exposure
3. performance and retry behavior
4. schema or API compatibility
5. observability and rollback safety
6. tests that should exist but are missing
Return markdown with these sections only:
- Summary
- Risks
- Suggested review comments
- Missing tests
- Rollout notes
"""

MODEL = os.getenv("REGOLO_CORE_MODEL", "qwen3.5-122b")

def get_git_diff() -> str:
    commands = [
        ["git", "diff", "--cached"],
        ["git", "diff", "HEAD~1", "HEAD"],
    ]
    for cmd in commands:
        result = subprocess.run(cmd, capture_output=True, text=True)
        if result.returncode == 0 and result.stdout.strip():
            return result.stdout
    raise RuntimeError("No diff found. Stage changes or run inside a repo with recent commits.")

def review_diff(model: str, diff_text: str) -> Dict[str, Any]:
    payload = {
        "model": model,
        "messages": [
            {
                "role": "system",
                "content": (
                    "You are a senior staff engineer reviewing a production pull request. "
                    "Be precise, avoid generic praise, and cite exact diff evidence."
                )
            },
            {
                "role": "user",
                "content": f"{ENGINEERING_CHECKLIST}\n\nDIFF:\n{diff_text[:120000]}"
            }
        ],
        "temperature": 0.1
    }

    r = requests.post(
        f"{BASE_URL}/v1/chat/completions",
        headers={
            "Authorization": f"Bearer {API_KEY}",
            "Content-Type": "application/json"
        },
        json=payload,
        timeout=180,
    )
    r.raise_for_status()
    return r.json()

def extract_content(resp: Dict[str, Any]) -> str:
    try:
        return resp["choices"][0]["message"]["content"]
    except Exception:
        return json.dumps(resp, indent=2)

def main():
    diff_text = get_git_diff()
    review = review_diff(MODEL, diff_text)

    print(f"# Regolo PR Review\n\nModel: `{MODEL}`\n")
    print(extract_content(review))

if __name__ == "__main__":
    main()
Code language: Python (python)

Output

Model: `qwen3.5-122b`



# Summary
This PR introduces a new tutorial directory `ai-governance-copyright/` containing a policy gateway implementation (`main.py`) and documentation. While the intent is educational, the code demonstrates patterns (PII redaction, policy enforcement, API interaction) that could be copied into production systems. The implementation lacks production-grade hardening regarding error handling, observability, and security controls.

# Risks
1.  **Security & PII Compliance (High):** `redact_pii()` (lines 53-55) relies on brittle regex patterns for PII removal. Claiming "Enterprise Risk" reduction based on regex redaction is dangerous; regex fails on edge cases (international formats, obfuscated data). This sets a false security precedent.
2.  **Reliability & Resilience (Medium):** `requests.get` and `requests.post` (lines 33, 63) lack retry logic. Transient network failures will cause immediate script termination. `timeout=120` (line 69) is excessive for chat completions and risks resource exhaustion.
3.  **Configuration Management (Medium):** `POLICY` rules (lines 19-25) and `BASE_URL` (line 17) are hardcoded. This prevents dynamic policy updates without code redeployment.
4.  **Observability (Medium):** Uses `print()` (lines 138, 156) instead of structured logging. No correlation IDs, timestamps, or log levels. Debugging production issues will be impossible.
5.  **Localization Consistency (Low):** Code comments and error messages are in Italian (e.g., line 16, 120), while README and docstrings are mixed English/Italian. This creates maintenance friction.
6.  **Secrets Handling (Medium):** `load_dotenv` (line 10) loads `.env` from the script directory. If `.env` is accidentally committed, secrets are exposed.

# Suggested review comments
- **`main.py:10-12`**: `load_dotenv` should be guarded by a check to ensure `.env` is not committed. Add a comment warning users to add `.env` to `.gitignore`.
- **`main.py:17`**: `BASE_URL` should be configurable via environment variable (`REGOLO_API_BASE_URL`) to allow switching between staging/prod without code changes.
- **`main.py:19-25`**: Move `POLICY` configuration to an external JSON/YAML file or environment variable. Hardcoding policy rules makes iteration slow and error-prone.
- **`main.py:33-36`**: Add retry logic (e.g., `tenacity` or `requests.adapters.HTTPAdapter` with `Retry`) for `get_models()`. Network blips should not fail the gateway.
- **`main.py:53-55`**: **Critical:** Add a disclaimer that regex PII redaction is not sufficient for GDPR/CCPA compliance. Recommend integrating a dedicated NER library (e.g., `presidio`) for production use cases.
- **`main.py:69`**: Reduce `timeout=120` to `30` or `60` seconds. Long timeouts block workers unnecessarily.
- **`main.py:120-125`**: The fallback to `BLOCK` on JSON parse error is safe, but log the raw response to a separate error channel for debugging, rather than just printing to stdout.
- **`main.py:138, 156`**: Replace `print()` with a logging library (`logging` module) using JSON format for structured observability.
- **`main.py:100-105`**: The `incoming_prompt` is hardcoded. Accept input via CLI arguments (`argparse`) or stdin to make the script reusable for testing different scenarios.
- **`README.md` (New File)**: Ensure the "Licenza" section matches the root repository license. Clarify that this is a "Reference Implementation" and not a drop-in production library.

# Missing tests
1.  **Unit Tests for `redact_pii`**: Test cases for edge cases (e.g., international phone numbers, emails with subdomains, IDs with hyphens).
2.  **Unit Tests for `get_models`**: Mock responses for `list`, `dict` with `data` key, and malformed JSON to ensure parsing robustness.
3.  **Unit Tests for `chat`**: Mock `requests.post` to verify headers (`Authorization`, `Content-Type`) and payload structure.
4.  **Integration Test**: Mock the entire flow to verify the `BLOCK` path triggers correctly when policy matches.
5.  **Error Handling Test**: Verify behavior when `REGOLO_API_KEY` is missing or invalid (HTTP 401).
6.  **Timeout Test**: Verify script behavior when the API endpoint hangs (ensure it respects the timeout).

# Rollout notes
- **Verification**: Before merging, verify that `.gitignore` explicitly excludes `.env` files to prevent accidental secret leakage in the tutorial repo.
- **Documentation**: Update the README to explicitly state: "This code is for educational purposes. Do not use regex PII redaction for production compliance without validation."
- **API Stability**: Confirm that `BASE_URL` endpoints (`/models`, `/v1/chat/completions`) are stable and versioned. If these are beta endpoints, add a warning in the README.
- **Language**: Decide on a primary language (English or Italian) for code comments and error messages to maintain consistency across the repository.
- **Dependency Pinning**: `requirements.txt` or `pyproject.toml` should be added to pin versions of `requests` and `python-dotenv` to prevent breaking changes in dependencies.Code language: Bash (bash)


Troubleshooting

If the review comments are too generic, the diff is usually too large or the output schema is too loose. Reduce scope first. For example, review only one service or one migration at a time, then expand once the signal quality is acceptable.

For CTOs, this pattern works because it augments the existing review process instead of trying to replace engineers. The model can compress routine review work, surface likely risks, and propose tests, while the human reviewer still owns approval. That is the right adoption pattern in a coding market shaped by agentic workflows and coding-first model releases.


FAQ

Should this run on every PR? 

Not at first. Start with high-change or high-risk repositories, then expand based on reviewer satisfaction.

Should I fine-tune before shipping this? 

Usually no. A strong checklist and a bounded output format deliver more value early than custom training.

What should I measure?

Reviewer acceptance rate of comments, time saved per PR, false-positive review comments, and the share of model-suggested tests that catch real regressions.


Github Codes

You can download the codes on our Github repo, just copy and paste the .env.example files and fill properly with your credentials. If need help you can always reach out our team on Discord 🤙


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