Native DeepSeek V4 (Pro / Flash) provider for VS Code Copilot Chat — with full extended-thinking support, agent-mode tool calling, and built-in cost tracking.
Features
Four model variants in the Copilot model picker: Pro (thinking), Pro, Flash (thinking), Flash
Extended thinking at max effort, with the full reasoning chain preserved across multi-turn agent loops
Agent-mode tool calling that does not break on the second turn
Status bar with live account balance and session spend (auto-detects CNY / USD)
Background balance refresh after each chat (debounced, silent)
Persistent reasoning cache (survives VS Code restarts)
Retry on transient failures (5xx, 429, network jitter)
What this plugin uniquely solves
Generic OAI-compatible bridges drop the reasoning_content field when forwarding to DeepSeek, which causes a hard 400 on the second turn of any tools-enabled thinking conversation:
The reasoning_content in the thinking mode must be passed back to the API.
This extension is a native VS Code Language Model Provider — it intercepts each request, restores the prior reasoning_content from a local cache, and re-attaches it to every assistant turn in history (not just the ones that called a tool, which is what DeepSeek actually requires when tools is present). Result: agent loops, multi-turn refactors and long thinking sessions work end-to-end.
Quick start
Install DeepSeek V4 for Copilot Chat from the VS Code Marketplace.
Run Manage DeepSeek V4 Provider from the command palette and paste your DeepSeek API key.
Open Copilot Chat, pick a DeepSeek V4 variant from the model picker, start chatting.
