DeepSeek V4 for Copilot Chat

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Pick DeepSeek V4 from the Copilot Chat model picker — and keep everything else Copilot already gives you.

Love DeepSeek's price-performance but don't want to give up GitHub Copilot's agent mode, tool calling, and polished UI? This extension adds DeepSeek V4 Flash, Pro, and Flash Vision Exp to the Copilot Chat model selector — with native vision or Vision Proxy, thinking mode, and your own API key.

Why this extension?

• Don't replace Copilot — power it up. No new sidebar, no new chat UI to learn. Just a new model in the picker you already use.
• Agent mode, tool calling, instructions, MCP, skills — all of it still works. Copilot's entire stack, now running on DeepSeek.
• Two ways to work with images. Flash Vision Exp receives image attachments natively. Flash and Pro keep their existing text context while a configurable Vision Proxy turns images into descriptions.
• BYOK, pay DeepSeek directly. Your API key, your bill, your rate limits. Stored in the OS keychain, never on disk.

Features

Three DeepSeek V4 models in the model picker

Flash, Pro, and the experimental Flash Vision Exp appear alongside other models in Copilot Chat's model selector. All three support DeepSeek's long context, tool calling, and configurable thinking effort.

Native Vision and Vision Proxy

Choose the image path that fits the conversation:

• DeepSeek V4 Flash Vision Exp handles image attachments as native multimodal input, without Vision Proxy. It is exposed as a separate experimental model and does not silently fall back when the configured API endpoint does not support its model ID.
• DeepSeek V4 Flash and Pro use Vision Proxy: an image-capable model first describes each attachment, then the main DeepSeek model receives the description with the conversation. Auto mode selects Flash Vision Exp when available, while an explicitly configured VS Code model or API endpoint remains supported.

Avoid switching models mid-chat just to inspect an image if DeepSeek prefix-cache reuse matters. Start the conversation with Flash Vision Exp for native vision, or stay on Flash/Pro and let Vision Proxy preserve the main model choice.

Thinking Mode with Reasoning Effort Control

Full support for DeepSeek V4's reasoning_content. Flash, Pro, and Flash Vision Exp offer none (off), low (light reasoning), high (balanced, default), and max (deep reasoning for hard agent tasks), matching the effort levels implemented by the official API.

Inherits Every Copilot Capability

Because this plugs into Copilot's native provider API, you get the full stack for free:

• Agent mode — autonomous multi-step tasks
• Tool calling — file edits, terminal, workspace search, Git, tests
• Instructions & skills — all your .instructions.md, AGENTS.md, and skills just work
• Prompt caching stats — DeepSeek's cache hit rate logged in the output channel so you can see the savings

Secure by Default

API key lives in VS Code's SecretStorage (OS keychain on macOS / Windows / Linux). Never in settings.json, never in your Git history.

Zero Runtime Dependencies

Pure VS Code API + Node.js built-ins. No Python, no Docker, no local proxy server to babysit.

Getting Started

Prerequisites

• VS Code 1.116 or later. This extension relies on non-public Copilot Chat APIs that may break on newer VS Code versions — report an issue if you hit one.
• GitHub Copilot subscription (Free / Pro / Enterprise — the free tier works)
• DeepSeek API key from platform.deepseek.com, or a compatible provider token when using a custom deepseek-copilot.baseUrl

Installation

Install from the registry used by your editor:

1. Microsoft VS Code — install from VS Code Marketplace.
2. Editors that use Open VSX — install from Open VSX.

Usage

1. Run DeepSeek: Set API Key from the Command Palette (Cmd+Shift+P)
2. Paste your key or compatible provider token (official DeepSeek keys usually start with sk-)
3. Open Copilot Chat, click the model picker, and choose DeepSeek V4 Flash, DeepSeek V4 Pro, or DeepSeek V4 Flash Vision Exp
4. That's it — chat away

Models

Model	Image Handling	Thinking Effort	Best For
DeepSeek V4 Flash	Vision Proxy	none / low / high / max	Fast everyday coding, quick edits, cheap iteration
DeepSeek V4 Pro	Vision Proxy	none / low / high / max	Complex refactors, agent tasks, deep reasoning
DeepSeek V4 Flash Vision Exp	Native image input	none / low / high / max	Direct, experimental image understanding with fast reasoning

All three support optional thinking mode, tool calling, and 1M token context. Flash Vision Exp is experimental; custom API endpoints and compatible providers must expose its configured model ID to use it directly.

Settings

Setting	Default	Description
deepseek-copilot.baseUrl	https://api.deepseek.com	API endpoint — change for self-hosted / proxied deployments
deepseek-copilot.maxTokens	0	Max output tokens (0 = no limit). Useful for cost control
deepseek-copilot.modelIdOverrides	prefilled official ID map	API model IDs to send for DeepSeek V4 Flash, Pro, and Flash Vision Exp. Change only for compatible third-party APIs with different model names
deepseek-copilot.debugMode	minimal	Diagnostic mode: minimal for token usage only, metadata for privacy-preserving logs, or verbose for full request dumps and pipeline snapshots under extension global storage. Full dumps may include sensitive prompt text, tool schemas, file snippets, and image descriptions. Use DeepSeek: Open Request Dumps Folder to open the dump location
deepseek-copilot.visionModel	(auto)	Vision Proxy used by Flash and Pro. Auto mode selects Flash Vision Exp when available; configure another VS Code model or API endpoint with DeepSeek: Configure Vision Proxy
deepseek-copilot.visionPrompt	(built-in)	Prompt used by Flash/Pro's Vision Proxy to describe image attachments. It does not affect native Flash Vision Exp requests
deepseek-copilot.experimental.stabilizeToolList	false	Experimental. Tries to pre-activate VS Code/Copilot virtual tools so the DeepSeek API tools parameter is more complete and stable across turns. May improve context-cache hit rate when enabled tools change between turns. Can increase input tokens because more function definitions may be included; cache-hit input tokens are cheaper but still count toward usage. Usually leave it off with 64 or fewer enabled tools unless the tool list still changes across turns; do not enable it with more than 128 enabled tools

Thinking Effort is configured from Copilot Chat's model picker for each DeepSeek model.

Example settings.json override for compatible API proxies:

{
  "deepseek-copilot.modelIdOverrides": {
    "deepseek-v4-flash": "your-flash-model-id",
    "deepseek-v4-pro": "your-pro-model-id",
    "deepseek-v4-flash-vision-exp": "your-vision-model-id"
  }
}

Compared to alternatives

	This extension	Local proxy (e.g. LiteLLM)	Standalone DeepSeek extensions
Works inside Copilot Chat	✅	✅	❌ separate UI
Agent mode, tools, skills	✅	✅	⚠️ reimplemented
Vision support	✅ native + proxied	❌	❌
No extra process to run	✅	❌	✅
One-click install	✅	❌	✅
API key in OS keychain	✅	❌	⚠️ varies

License

MIT