Agent Router — @router

Routes GitHub Copilot Chat prompts to standard (1x) or advanced (2x+) 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 cost-efficient Copilot model — using powerful advanced models only when they're actually needed.

@router <your prompt>
      │
      ▼
  Complexity Score (0–100)
  via keyword heuristics
      │
      ├─ Score ≤ threshold → 🟢 Standard (1x)   (gpt-5-mini, gpt-5.6-luna, mai-code-1.1-flash)
      └─ Score >  threshold → 🔴 Advanced (2x+)  (claude-sonnet-5.0, gpt-5.6-terra, gpt-5.3-codex, claude-opus-5.0)
      │
      ▼
  Full agentic loop with 30 tools (file edits, terminal, search, git…)
  Response streamed back into Copilot Chat

Installation

Option A — From .vsix File (Manual)

1. Download the latest .vsix from Releases
2. Open VS Code → Extensions sidebar (Ctrl+Shift+X)
3. Click the ··· menu (top-right) → Install from VSIX…
4. 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)
• GitHub Enterprise users: Set agentRouter.githubEnterpriseUrl to your enterprise URL (e.g. https://company.ghe.com) in VS Code settings

Usage

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

Command Palette Commands

Examples

@router how do I reverse a string in Python?
→ 🟢 Standard tier (gpt-5-mini) — 1x cost, low complexity

@router design a distributed OAuth2 auth system with Kubernetes and Redis caching
→ 🔴 Advanced tier (claude-sonnet-5.0) — 2x cost, high complexity

@router /claude-sonnet-5.0 refactor my auth module
→ 📌 Pinned model (claude-sonnet-5.0)

@router /claude-sonnet-5.0 /boost implement missing methods
→ 📌 Pinned model (claude-sonnet-5.0), expands prompt with history, then generates answer

@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

Chat Memory

Starting with v1.8.0, all model requests — routing, agentic tool loops, simple responses, and /boost prompt expansion — automatically include the preceding turns of your current Copilot Chat session as context. This lets the model reference earlier questions and answers in the same conversation without you repeating yourself.

Context-length note: Each prior turn adds tokens to the request. Very long conversations may approach a model's context window limit. If you notice slower responses or truncated answers, start a new chat session to reset the history.

Privacy note: Conversation history is passed to the selected Copilot model (the same model that already handles your prompt). No history is stored or sent anywhere outside of the active Copilot session.

Premium Quota & Dashboard 📊

Agent Router makes a best-effort attempt to track your Premium Request limits using an internal/undocumented GitHub Copilot endpoint. This is not an official, supported public API, so it may change, become unavailable, or be inaccessible for some accounts without notice.

• Status Bar Indicator: View your remaining premium request count and dynamic capacity percentage conveniently in the VS Code status bar when quota data is available.
• Copilot Insights Dashboard: Click the status bar or run Agent Router: Show Premium Stats to open the interactive dashboard with:
  • Usage gauge and quota breakdown
  • Per-model usage distribution with bar charts
  • Chat Conversations — all workspace conversations (both @router and regular Copilot Chat) in a single view, clickable to see the full conversation thread
  • Individual request log with status, model, tier, score, estimated tokens, and cost multiplier
  • Active session monitoring
  • Workspace Copilot configuration overview (instructions, prompts, agents, skills, hooks)
• Expected failure modes: Depending on your account, Copilot plan, authentication state, token scopes, GitHub backend changes, rate limits, or response-format changes, premium-usage data may be missing, partial, stale, or fail to load entirely.
• Fallback behavior: If quota data cannot be retrieved, Agent Router will continue to route prompts and provide chat/agent functionality as normal; only the premium-usage indicator/dashboard may be degraded or unavailable.

Chat History & Export 📜

Agent Router reads VS Code's internal Copilot Chat session files (chatSessions/) to give you visibility into all workspace conversations — not just @router sessions. It correctly parses the JSONL patch format including custom titles, appended requests, and streamed responses.

Viewing Conversations

The Copilot Insights Dashboard (Agent Router: Show Premium Stats) shows a Chat Conversations table listing every conversation in the workspace. Each row shows:

• Source badge: Copilot Chat (purple) or @router (blue)
• Title, models used, turn count, estimated tokens, cost
• Click any row to open the full conversation in a chat-style detail panel

Exporting to Markdown

Transferring Chats Between Workspaces (JSON)

Move live conversations between VS Code instances (e.g., Windows ↔ WSL, or between machines):

1. Source workspace — Run Export Chat History to JSON
   • Make sure the chat you want to export is the active chat tab
   • Save the .json file to a shared location
2. Target workspace — Run Import Chat History from JSON
   • Select the .json file
   • The chat opens as a new live tab in Copilot Chat — fully functional, continue the conversation

This uses VS Code's built-in workbench.action.chat.export / workbench.action.chat.import commands, so imported chats appear natively in the Chat sidebar — no window reload needed.

Configuration

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

🛠️ Cost Multipliers & Model Tiers

Models are categorized by cost multiplier — how many premium requests each call consumes.

Standard Models (1x cost)

Advanced Models (2x+ cost)

Models not in this table default to 2x. The preferred advanced model is claude-sonnet-5.0.

Custom Routing Rules

Override automatic routing for specific prompts via agentRouter.routingRules in settings:

"agentRouter.routingRules": [
  { "pattern": "security|CVE|vulnerability", "tier": "advanced" },
  { "pattern": "translate|simple question", "tier": "standard" },
  { "pattern": "codex", "model": "gpt-5.3-codex" }
]

Rules are evaluated in order. First regex match wins. If no rule matches, normal complexity scoring applies.

Complexity Scoring

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

Agentic Tools (30 tools)

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

Terminal Execution: Headless vs Visible

The agent possesses two distinct tools for running terminal commands:

1. Headless Execution (runCommand): By default, when you ask the agent to run scripts, build apps, or fix errors, the agent runs the command headlessly in the background. This is highly recommended because it forces the agent to wait for the command to finish, read the resulting stdout/stderr, and intelligently fix any errors if it fails. You can view the logs for these headless commands by expanding the tool calls in the Chat panel.
2. Visible Execution (openTerminal): You can explicitly ask the agent to "run this in a visible terminal panel" (or specify a tab name like "wsl" or "powershell"). The agent will open a VS Code terminal and paste the command. Warning: This is a blind, fire-and-forget action. The agent cannot see the output and cannot wait for it to finish. Use this only for infinite-running dev servers (e.g., npm run dev) or when you just want to take over manually.

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-1.11.0.vsix

License

MIT — see LICENSE