Agent Router — `@router`

Routes GitHub Copilot Chat prompts to free or premium models based on complexity — with full agentic file-edit, terminal, and workspace capabilities.

Author: Adnan Okay

What It Does

Agent Router integrates with GitHub Copilot Chat as a native @router chat participant. It scores the complexity of your prompt (0–100) and automatically routes it to the most appropriate Copilot model — so you use powerful premium models only when they're actually needed.

@router <your prompt>
      │
      ▼
  Complexity Score (0–100)
  via keyword heuristics
      │
      ├─ Score ≤ threshold → 🟢 Free model      (gpt-4.1, gpt-4o, gpt-5-mini)
      └─ Score >  threshold → 🔴 Premium model  (claude-sonnet-4.6, gemini-3-pro, gpt-5.3-codex…)
      │
      ▼
  Full agentic loop with 30 tools (file edits, terminal, search, git…)
  Response streamed back into Copilot Chat

Installation

Option A — From `.vsix` File (Manual)

Download the latest .vsix from Releases
Open VS Code → Extensions sidebar (Ctrl+Shift+X)
Click the ··· menu (top-right) → Install from VSIX…
Select the downloaded file and reload VS Code

Option B — VS Code Marketplace

Search for "Agent Router" in the Extensions panel, or:

ext install local.agent-router-extension

Prerequisites

VS Code ^1.95.0
GitHub Copilot extension installed & active
Active GitHub Copilot subscription (for premium model access)

Usage

Open Copilot Chat (Ctrl+Alt+I / ⌘⌥I) and type:

Command	Description
`@router <prompt>`	Score, route and answer your prompt
`@router /help` or `@router /?`	Show the full help page
`@router /explain <prompt>`	Show routing decision (score, tier, model) — no LLM call
`@router --model <name> <prompt>`	Pin a specific model, bypass auto-routing

Examples

@router how do I reverse a string in Python?
→ 🟢 Free tier (gpt-4o) — low complexity

@router design a distributed OAuth2 auth system with Kubernetes and Redis caching
→ 🔴 Premium tier (claude-3.5-sonnet) — high complexity

@router --model claude-3.5-sonnet refactor my auth module
→ 📌 Pinned model (claude-3.5-sonnet)

@router /explain refactor my authentication module for microservices
→ Shows score breakdown without making any model call

@router /help
→ Shows full help, available models, and tool list

Configuration

Setting	Type	Default	Description
`agentRouter.freeThreshold`	`number`	`70`	Complexity score (0–100). Scores ≤ this go to a free model.
`agentRouter.agentMode`	`boolean`	`true`	Enable/disable the full agentic tool-calling loop.

Open Settings (Ctrl+,) and search agentRouter to adjust.

Free Model Families

gpt-4.1, gpt-4o, gpt-5-mini

All other available Copilot models (e.g. claude-sonnet-4.6, gemini-3-pro, gpt-5.3-codex) are treated as premium.

Complexity Scoring

Prompts are scored 0–100 using fast non-blocking keyword heuristics:

Factor	Points	Trigger
Base score	+10	All prompts
Length bonus	+25	Long prompts
Multi-step structure	+8	4+ lines
Dense technical syntax	+7	Code-heavy content
Architecture / Distributed	+20	kubernetes, microservices, load balancing…
Security / Auth / Encryption	+20	OAuth2, JWT, TLS, cryptography…
ML / Neural Networks	+18	transformers, NLP, embeddings…
Performance / Optimization	+15	caching, indexing, profiling…
Refactoring / Migration	+12	legacy, upgrade, deprecation…
Deep Debugging / Root-cause	+10	memory leak, deadlock, race condition…

Agentic Tools (30 tools)

When agentRouter.agentMode is true, @router can call these tools during the response:

Category	Tools
File	`readFile`, `writeFile`, `editFile`, `deleteFile`, `renameFile`, `copyFile`, `createDirectory`, `readFileLines`, `findAndReplace`
Search	`searchFiles`, `listDirectory`
Code	`getSymbols`, `getProblems`, `showDiff`
Editor	`openFile`, `getSelectedText`, `insertSnippet`, `listOpenEditors`
Terminal	`runCommand`, `runTests`, `getTerminalOutput`, `openTerminal`
Git	`getGitStatus`
VS Code	`getWorkspaceInfo`, `getExtensionSettings`, `getExtensionList`, `showNotification`
Clipboard	`clipboardRead`, `clipboardWrite`
Network	`fetchUrl`

Development

git clone https://github.com/adnnoky/github-copilot-agent-router.git
cd github-copilot-agent-router
npm install
npm run compile   # one-time build
npm run watch     # watch mode
# Press F5 to launch Extension Development Host

# Package for distribution
npx vsce package
# Install locally
code --install-extension agent-router-extension-1.5.0.vsix

License

MIT — see LICENSE

Agent Router

Adnan Okay

Agent Router — @router