Codex + VS Code Engineering Methodology

A practical methodology for disciplined AI-assisted software development with Codex inside VS Code.

The goal is to turn AI coding from an improvised chat workflow into a controlled engineering process:

Understand
→ Scope
→ Inspect
→ Plan
→ Implement
→ Verify
→ Review Diff
→ Document
→ Handoff

Core model

VS Code is the engineering cockpit.
It provides the workspace, files, terminal, diffs, source control, tests, logs and human review surface.

Codex is the implementation agent.
It reads the repository, proposes bounded changes, edits code, runs focused verification and reports exactly what changed.

The human remains the owner of:

• architecture decisions;
• scope;
• approval of destructive actions;
• production access;
• secrets;
• final review;
• release decisions.

Main principles

1. Repository truth before assumptions
2. Small, bounded tasks
3. Inspect before edit
4. Reuse before creating
5. Exact-file ownership
6. Focused verification first
7. Diff is part of the deliverable
8. Stop on unknown scope
9. No silent destructive actions
10. Document important decisions
11. Handoff before context is lost
12. AI assists the engineering process; it does not replace engineering ownership

Recommended workflow

Task
↓
Context Gate
↓
Recon
↓
Change Plan
↓
Implementation
↓
Focused Tests
↓
Diff Review
↓
Runtime Check
↓
Final Report
↓
Commit / Handoff

Task modes

R — Recon

Read-only investigation.

Use when the repository state, ownership, contract or safest implementation path is unclear.

F — Feature

A bounded implementation task with a known goal and known ownership.

V — Verification

Review, regression proof, contract validation or diff audit.

H — Handoff

Capture current state for the next coding session.

Repository structure

codex-vscode-engineering-methodology/
├── README.md
├── docs/
│   ├── 01-operating-model.md
│   ├── 02-task-lifecycle.md
│   ├── 03-context-gate.md
│   ├── 04-recon-before-edit.md
│   ├── 05-change-scope.md
│   ├── 06-vscode-workspace-discipline.md
│   ├── 07-terminal-and-command-safety.md
│   ├── 08-testing-and-verification.md
│   ├── 09-diff-review.md
│   ├── 10-stop-conditions.md
│   ├── 11-commit-discipline.md
│   └── 12-handoff-discipline.md
├── templates/
│   ├── R-recon-template.md
│   ├── F-feature-template.md
│   ├── V-verification-template.md
│   ├── H-handoff-template.md
│   ├── change-plan-template.md
│   └── final-report-template.md
└── examples/
    └── end-to-end-example.md

Philosophy

The methodology is designed around one idea:

Codex should never be asked to "just change the code."
It should be given a bounded engineering contract: what to inspect, what it owns, what it must preserve, how success is proven, and when it must stop.

That makes AI-assisted coding more reviewable, repeatable and safe.