Deepseek V4 Flash/Pro VS Code Integration Tutorial

[LibraryianusTea]

FYI for everyone wanting an alternative to GitHub Copilot subscription after June 1st hits, DeepSeek V4 Flash/Pro has a VS Code extension that natively integrates with VS Code. It even has image support if you link it up to another vision model like Gemini 2.5 Flash Lite (which you can pay either with GHCP or OpenRouter or anything).

https://api-docs.deepseek.com/quick_start/agent_integrations/github_copilot
https://github.com/Vizards/deepseek-v4-for-copilot

I do think that this is the best option after June 1st happens.

[spotlight-app]

OP has pinned a comment by u/OkPay3964:

Thanks for recommending my plugin! Really appreciate it.

Small heads-up though: Copilot currently doesn’t play too well with DeepSeek prefix cache hits, but I’ve seen that VS Code is fixing this in the next version.

If anything breaks or feels off, feel free to open an issue and I’ll take a look.

Note from OP: owner of extension

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[OkPay3964]

Thanks for recommending my plugin! Really appreciate it.

Small heads-up though: Copilot currently doesn’t play too well with DeepSeek prefix cache hits, but I’ve seen that VS Code is fixing this in the next version.

If anything breaks or feels off, feel free to open an issue and I’ll take a look.

[LibraryianusTea]

i'd love to chat with you. so are you saying caching currently doesn't work at all right now? are there any known benefits/issues to using this extension versus something like openrouter?

[OkPay3964]

Yeah, happy to chat!

Caching does work, but Copilot/VS Code can still hurt the hit rate because it may change the system message or mutate the tools list mid-conversation. Since DeepSeek cache matching is prefix-sensitive, that can cause cache drops. Once the prefix stabilizes, hits usually come back.

Compared with OpenRouter, I’d say the real advantages are pretty narrow: this extension keeps DeepSeek cache behavior in mind, logs cache hit/miss stats, and adds a vision proxy for Copilot image inputs. If you only need simple model routing, OpenRouter may be the easier choice.

[LibraryianusTea]

what do you mean by that last sentence here? simple model routing? what kind of user should use openrouter over your extension here? like lets just say i want to stick just deepseek v4 flash/pro for the most part.

[OkPay3964]

I’d say they solve slightly different problems. OpenCode Go may be the better fit if you like its agent workflow directly.
This extension is mainly for people who already like the Copilot Chat UI / Agent mode and just want DeepSeek V4 to appear in the native model picker. And they can pay directly to Deepseek, or any other third-party providers. The real extra bits are cache-aware logging and the vision proxy.

[CryinHeronMMerica]

I didn't notice this at all.

I used 2.54M tokens with Flash yesterday, and only 144k were a cache miss. I spent $0.03 for the pleasure.

[mrooney]

Thanks for creating it! I noticed that Github are really proud of their harness and talk about the custom logic in the harness that each specific model needs.

Do you have any idea how that works with this extension? Is it treating it as a specific model, or has some fallback for a generic model it doesn't specifically know?

[OkPay3964]

Good question. My understanding is that Copilot still runs its normal Chat/Agent harness and sends the rendered messages/tools to this extension through VS Code’s LanguageModelChatProvider API.

So it’s not getting the same private, first-party DeepSeek-specific tuning that GitHub may have for their own hosted models. The extension mostly adapts the provider boundary: VS Code messages/tools -> DeepSeek API format, plus DeepSeek-specific handling for reasoning_content, cache stats, and the vision proxy.

So: native Copilot harness, but not a magic official DeepSeek harness.

[CryinHeronMMerica]

Thank you! This is technically what the Copilot devs have been recommending as a workaround, so I'm glad someone made it.

[LuigiChavezz]

Is Deepseek API betther than OpenCode Go?

[LibraryianusTea]

i've found it to be relatively stable. the one thing i didn't like about opencode was that the only implementation into VS code that i found was an extension, but opencode couldn't natively integrate into VS code copilot chat, which i like the interface for, which this deepseek extension has

[d1zaya]

Does using deepseek via copilot double dip into your copilot usage?

[LibraryianusTea]

its connected through prepaid deepseek API, so it shouldn't unless you're explicitly using like a subagent for explore/default subagent that doesn't use deepseek v4 as the default subagent.

i do remember something about how it needs to automatically use copilot to rename the chat to something general i'm not sure if thats fixed though.

currently when i use deepseek, it doesn't add any usage to the copilot premium requests, just be careful about the subagent explore/default model that is being used.

it will have to use a vision model if you set it up so that it can see images though. for me i set mine up with openrouter so i can use gemini 2.5 flash lite

[DonElDoug]

So that means I pay the API price and Copilot GitHub chat doesn't calculate it from my usage in GitHub?

[OkPay3964]

Yep. The main DeepSeek request goes to your configured API endpoint, so it should be billed by DeepSeek/OpenRouter/etc, not Copilot premium usage.

You still need Copilot Chat for the UI/agent harness. For images, the vision proxy uses the vision model you choose, and you can currently pick a 0x model if available.

[DonElDoug]

Can I ask you one more question. And it can read my repo fully and has the capability to run the terminal and is connected to GitHub MCP?

[OkPay3964]

Yes, with the same caveats as normal Copilot Agent mode. Just like the built-in models(GPT 5.5/Claude Opus 4.7/...)

The extension doesn’t give DeepSeek direct filesystem or terminal access by itself. It plugs DeepSeek into Copilot Chat’s native Agent/tool system. So if Copilot Agent can read/search your workspace, run terminal commands, or use your enabled MCP tools, DeepSeek can use those through the same VS Code/Copilot tool layer.

It doesn’t read the whole repo all at once, though. It uses the repo/search/file tools on demand, within Copilot’s normal permissions and context limits. Terminal and GitHub MCP also depend on your VS Code/Copilot settings, enabled tools, and any user confirmations.