🛡️ Copilot Sentinel v2

AI-powered code review, pattern detection, and auto-context for GitHub Copilot

Your codebase has a story. Sentinel reads it — so Copilot doesn't have to waste premium requests figuring it out.

What is Copilot Sentinel?

Copilot Sentinel is a VS Code extension that sits between your project and GitHub Copilot. It does two things:

1. Keeps Copilot informed — auto-generates and maintains .github/copilot-instructions.md so Copilot already knows your tech stack, architecture, and conventions before you ask anything.
2. Runs local agents — code review, duplicate detection, project analysis, and context enrichment — all without burning a single premium request.

Why You Need This

GitHub Copilot Pro gives you 300 premium requests/month. Without Sentinel:

Sentinel does all of this locally, for free, automatically.

Features

🔄 Auto Baseline Sync

Sentinel scans your project and generates .github/copilot-instructions.md — the file Copilot reads automatically. It includes your tech stack, dependencies, folder structure, entry points, and architecture.

• Auto-syncs on save (debounced, configurable)
• Delta-sync — only writes when content actually changes
• Multi-framework — Node.js, Python, Flutter, Rust, Go, Java, PHP, Ruby, C#, Swift

🔍 Code Review Agent

Static analysis across your entire project. Detects:

• Long files and functions
• Deep nesting
• Empty catch blocks
• console.log / debug statements
• TODO/FIXME comments
• Magic numbers
• any type usage (TypeScript)
• Duplicate imports
• Complex conditions
• Too many function parameters

Each file gets a quality score (0–100) with specific line numbers and fix suggestions.

🔗 Common Pattern Agent

Finds what your codebase has in common with itself:

• Import frequency — which modules are used everywhere
• Duplicate code blocks — exact matches across different files
• Similar file pairs — files with overlapping structure (Jaccard similarity)
• Shared patterns — repeated try-catch, validation, logging, singletons

📊 Project Analyzer Agent

Deep structural analysis:

• Import graph — who imports what
• Circular dependencies — detected and reported
• Orphan files — files never imported by anything
• Coupling scores — most connected files
• Complexity metrics — lines, functions, imports per file
• Architecture layers — auto-detected (controllers, services, models, etc.)

📝 Auto Context Agent

Takes findings from all three agents and enriches your copilot-instructions.md with:

• Detected code conventions
• Most used modules
• Architecture layers
• Circular dependency warnings
• Common patterns
• Quality summary
• AI-specific guidelines

Result: Copilot gets a complete understanding of your project without spending a single request.

💾 Shadow Cache

Save and reuse AI conversations locally:

• Save prompts + responses with tags
• Save selected code from the editor (right-click)
• Search across all cached entries
• Import/export as JSON
• Insert cached snippets at cursor

📈 Token Savings Dashboard

Visual proof of how much Sentinel is saving you:

• Lifetime tokens saved
• Dollar value saved
• Daily/weekly/monthly breakdowns
• Quota recovery gauge
• Per-event breakdown chart

How to Use

Quick Start

1. Install Copilot Sentinel from the VS Code marketplace
2. Open a project — Sentinel activates automatically and syncs the baseline
3. That's it — Copilot now reads your project context from .github/copilot-instructions.md

Run the Agents

Open the Command Palette (Ctrl+Shift+P / Cmd+Shift+P) and type Sentinel:

View Results

Option 1: Output Channel

After agents run, the Output panel opens automatically with formatted tables:

┌──────────────────────────────────────────────────────────────┐
│  🔍  CODE REVIEW RESULTS                                    │
├──────────────────────────────────────────────────────────────┤
│  Avg Quality Score : 82.3/100
│  Total Issues      : 14
│  ├─ Errors         : 2
│  ├─ Warnings       : 5
│  Files with Issues:
│  ⚠️ src/scanner.ts  (score: 65, 681 lines, 5 issues)
│     🔴 L  42  [file-length] File is 681 lines (max 300).
│              💡 Extract related logic into separate files.
└──────────────────────────────────────────────────────────────┘

Option 2: Agent Dashboard

Run Sentinel: Agent Dashboard for a visual interface with tabs:

• Overview — files analyzed, avg score, issues, duplicates, circular deps
• Code Review — per-file scores, issue tables, severity breakdown
• Patterns — shared patterns, import frequency, duplicate blocks, similar files
• Analysis — import graph stats, circular deps, coupled files, complexity table
• Context — detected conventions, generated enrichment preview

Shadow Cache

• Sentinel: Save to Shadow Cache — save a prompt + response
• Sentinel: Save Selection to Shadow Cache — right-click selected code
• Sentinel: Open Shadow Cache — search and browse all entries
• Sentinel: Import Shadow Cache — import from a JSON file

Auto Features

Flow Diagram

┌─────────────────────────────────────────────────────────────┐
│                        VS Code                              │
│                                                             │
│  ┌──────────┐    ┌─────────────────────────────────────┐   │
│  │ Your Code │    │        Copilot Sentinel              │   │
│  │           │───▶│                                     │   │
│  └──────────┘    │  ┌─────────────────────────────┐    │   │
│       │           │  │     Baseline Scanner         │    │   │
│       │ on save   │  │  Detect → Scan → Generate    │    │   │
│       │           │  └──────────────┬──────────────┘    │   │
│       │           │                 │                    │   │
│       │           │  ┌──────────────▼──────────────┐    │   │
│       │           │  │        Agent Suite            │    │   │
│       │           │  │  ┌────────┐ ┌────────────┐   │    │   │
│       │           │  │  │ Review │ │  Patterns   │   │    │   │
│       │           │  │  └────────┘ └────────────┘   │    │   │
│       │           │  │  ┌────────┐ ┌────────────┐   │    │   │
│       │           │  │  │Analyze │ │Auto Context │   │    │   │
│       │           │  │  └────────┘ └────────────┘   │    │   │
│       │           │  └──────────────┬──────────────┘    │   │
│       ▼           │                 ▼                    │   │
│  ┌──────────┐    │  ┌─────────────────────────────┐    │   │
│  │ .github/  │◀──│  │  copilot-instructions.md     │    │   │
│  │ copilot-  │    │  │  ┌─ Tech Stack              │    │   │
│  │ instruct- │    │  │  ├─ Architecture             │    │   │
│  │ ions.md   │    │  │  ├─ Agent Insights           │    │   │
│  └──────────┘    │  │  ├─ Conventions              │    │   │
│       │           │  │  ├─ Circular Dep Warnings    │    │   │
│       │           │  │  └─ AI Guidelines            │    │   │
│       ▼           │  └─────────────────────────────┘    │   │
│  GitHub Copilot   └─────────────────────────────────────┘   │
│  reads this file                                            │
│  as context                                                 │
└─────────────────────────────────────────────────────────────┘

Settings Reference

Baseline Settings

Agent Settings

Shadow Cache Settings

Supported Languages

All Commands

Privacy

Everything runs locally inside VS Code. No data is sent to any server. The only file written is .github/copilot-instructions.md in your workspace — which GitHub Copilot reads automatically as project context.

License

MIT