# Case Study: Automated Pull Request Review — Advanced Agent Workflows and Skills

Source: https://www.geekswithgeeks.com/en/agent-workflows/wrap-case-study

> Design a PR review workflow from the patterns in this course and explain each choice.

## Design choices

Trigger: a pull request opens. A **router** checks the changed paths. A **parallel** step runs a security reviewer and a test-gap reviewer as read-only **subagents**. A **skill** supplies the team's review checklist. An **orchestrator** merges findings into one comment. A **hook** or CI check blocks any write access, and a human decides whether to merge.

## A complete workflow

A real workflow combines a pattern, a skill, a subagent, hooks and an eval into one dependable loop.

![Four parts working together.](assets/figures/agent-workflows/section-8-map.svg) — Figure 8.1 — Pattern, skill, hooks and eval working together.

## The flow in outline

Read it as a diagram in text form. Each box maps to a concept from an earlier section.

```text
PR opened
  -> route by changed paths                (routing)
  -> [security reviewer | test-gap reviewer]  (parallel subagents, read-only)
  -> merge findings with checklist skill     (orchestrator + skill)
  -> post ONE comment                        (limited write tool)
  -> human decides to merge                  (checkpoint)
  -> eval set re-run when prompts change     (evals)
```

**Quiz:** Why is the final merge decision left to a human?

- [ ] Models cannot read code
- [x] It is a high-impact action, so a checkpoint is safer
- [ ] Git forbids bots
- [ ] It is cheaper to guess

*Answer:* It is a high-impact action, so a checkpoint is safer. High-impact, hard-to-undo actions deserve human approval.