Agent Code Extension

A Gemini Extension for structured feature planning and implementation with Codex-driven reviews. This extension provides a disciplined engineering workflow to ensure high-quality, testable, and well-documented code changes.

Overview

The Agent Code Extension facilitates a professional software development lifecycle within the Gemini CLI. It breaks down complex feature requests into manageable, plan-driven tasks, leveraging specialized sub-agents for implementation and expert code review.

Core Workflows

📝 Plan (/plan)

Collaborative feature planning that produces a verified implementation plan.

• Requirements Discussion: Refine scope and constraints with the user.
• Initial Documentation: Draft plan.md and tasks.md in a dedicated session folder.
• Codex Review Loop: Mandatory plan scrutiny by the codex-analyzer sub-agent.
• Final Approval: User sign-off on the hardened plan before implementation begins.

🛠️ Implement (/impl)

Iterative implementation of an approved plan with automated tasks and continuous review.

• Plan Analysis: Internalize the session plan and verify constraints.
• Task Breakdown: Divide work into small, independent tasks (1-3 files each).
• Iterative Cycle: For each task:
  1. Implement changes using task-implementer.
  2. Run automated tests to verify behavior.
  3. Perform Codex-driven code review for quality and security.
  4. Commit changes with standardized messages.
  5. Update session documentation (tasks.md and plan.md).

🚀 Commit (/commit)

Standardized git commit generation following the Conventional Commits specification with emoji prefixes.

• Format: <emoji> <type>(<optional scope>): <description>
• Types: feat, fix, docs, style, refactor, perf, test, build, ci, chore.

Specialized Sub-Agents

🔍 codex-analyzer

An expert code analysis orchestrator that uses the Codex CLI to perform deep technical reviews. It identifies:

• Logic bugs and edge cases.
• Security vulnerabilities.
• Performance bottlenecks.
• Architectural inconsistencies.

👷 task-implementer

A disciplined implementation specialist focused on delivering incremental, high-quality code. It adheres to:

• Pattern-First Development: Matches existing codebase conventions.
• Test-Driven Approach: Ensures every change is accompanied by verification logic.
• Scope Discipline: Limits changes to 1-3 files per task to maintain reviewability.

File Structure

• agents/: Instruction sets for specialized sub-agents.
• commands/: TOML definitions for top-level extension commands.
• skills/: Detailed procedural guidance for the development lifecycle.
• gemini-extension.json: Extension configuration and metadata.
• GEMINI.md: Core mandate and workflow summary for the agent.

Getting Started

1. Plan a Feature:

   /plan "Add user authentication using JWT"
   

2. Implement the Plan:

   /impl .agents/sessions/2026-02-26-user-auth
   

3. Commit Changes:

   /commit "Add login endpoint"
   

---

Built for disciplined engineering and high-quality software delivery.