OpenCode for Copilot Chat

Use OpenCode Go open coding models in the Copilot Chat model picker — and keep everything else Copilot already gives you.

Love the open coding models on OpenCode Go but don't want to give up GitHub Copilot's agent mode, tool calling, and polished UI? This extension drops GLM-5.2, Kimi K2.7 Code, DeepSeek V4, MiMo, MiniMax, and Qwen straight into the Copilot Chat model selector — with vision, thinking mode, and your own OpenCode Go API key. just need a small purchase to use it

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.
• All 14 OpenCode Go models. GLM-5.2/5.1, Kimi K2.7 Code/K2.6, DeepSeek V4 Pro/Flash, MiMo V2.5/V2.5 Pro, MiniMax M3/M2.7/M2.5, and Qwen3.7 Max/Plus/3.6 Plus — one API key, one extension.
• Mixed protocols handled automatically. GLM/Kimi/DeepSeek/MiMo run on the OpenAI /chat/completions endpoint; MiniMax/Qwen run on the Anthropic /v1/messages endpoint. The extension routes each model to the right endpoint automatically.
• Agent mode, tool calling, instructions, MCP, skills — all of it still works. Copilot's entire stack, now running on your OpenCode Go subscription.
• Vision where each model needs it. Images are transparently described by the vision proxy first, then passed along as text. If no vision model is configured, the extension falls back to another Copilot/VS Code vision model.
• Estimated per-turn cost. When the API returns usage, the extension estimates the list-price cost in USD, reports it to Copilot usage metadata, writes it to logs, and shows the latest turn in the status bar.
• BYOK, pay OpenCode directly. Your OpenCode Go API key, your $5/month subscription, your rate limits. Stored in the OS keychain, never on disk.

Features

GLM-5.2/5.1, Kimi K2.7 Code/K2.6, DeepSeek V4 Pro/Flash, MiMo V2.5/V2.5 Pro, MiniMax M3/M2.7/M2.5, and Qwen3.7 Max/Plus/3.6 Plus in the model picker

All three models show up alongside GPT-4o, Claude, and friends in Copilot Chat's model selector. Switch models mid-chat without losing history.

Transparent Vision Proxy

Drop a screenshot into chat and the automatic proxy describes it before the selected model receives the prompt. If no vision model is available on the current endpoint or plan, the extension falls back to another installed Copilot/VS Code vision model. You can also force a VS Code model or a custom API endpoint from OpenCode: Configure Vision Proxy.

This keeps GLM-5.2 focused on coding/reasoning while GLM-4.6V-Flash handles multimodal extraction.

Thinking Mode with Reasoning Effort Control

Full support for GLM's reasoning_content. Use Copilot Chat's native model picker menu to choose none (off), high (balanced), or max (default deep reasoning for hard agent tasks).

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 — GLM'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.

Cost Visibility

After each completed GLM response, the extension reports usage to Copilot metadata and writes it to logs. The status bar shows the latest turn and session total. Estimates use the official GLM list prices for the current endpoint currency: CNY for domestic BigModel endpoints and USD for Z.ai endpoints. Coding Plan requests also show an approximate list-price equivalent when token usage is returned.

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)
• OpenCode Go subscription ($5 for your first month, then $10/month). Subscribe at opencode.ai/auth and copy your API key. The GLM Coding Plan and Z.ai endpoints are also supported via the endpoint setting.

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. Subscribe to OpenCode Go and copy your API key from opencode.ai/auth
2. Run OpenCode: Set API Key from the Command Palette (Cmd+Shift+P / Ctrl+Shift+P)
3. Paste your OpenCode Go API key — it's stored in VS Code's secure SecretStorage (OS keychain)
4. Open Copilot Chat, click the model picker, pick any OpenCode Go model (GLM-5.2, Kimi K2.7 Code, DeepSeek V4 Flash, etc.)
5. That's it — chat away!

Models

All 14 OpenCode Go models are available. The extension automatically routes each model to the correct endpoint protocol:

OpenAI endpoint (OpenCode Go)

Anthropic endpoint (OpenCode Go)

All models support tool calling. GLM-5.2 and GLM-5.1 support thinking mode with reasoning effort control (none / high / max). Image attachments go through the Vision Proxy.

Settings

Thinking Effort is configured from Copilot Chat's model picker for each thinking-capable GLM model.

Example settings.json for a custom API proxy:

{
  "glm-copilot.baseUrl": "https://proxy.example.com/v1",
  "glm-copilot.customModels": [
    "my-model",
    {
      "id": "team-coder",
      "name": "Team Coder",
      "maxInputTokens": 200000,
      "maxOutputTokens": 131072,
      "toolCalling": true,
      "thinking": true
    }
  ],
  "glm-copilot.modelIdOverrides": {
    "glm-5.2": "your-glm-5.2-model-id"
  }
}

Troubleshooting

GLM models are missing from the agent / background agent model picker

Recent VS Code versions gate custom providers from the background agent and the new agent window. If you can pick GLM in the editor chat but not in the agent window, add the extension to the allowlist in settings.json:

{
  "extensions.supportUntrustedWorkspaces": true,
  "extensions.supportAgentsWindow": {
    "abbalochdev.opencode-for-copilot": true
  }
}

If the agent still refuses to start with No utility model is configured for 'copilot-utility-small' while the selected main model is BYOK, that is a known VS Code Copilot regression — see microsoft/vscode#324007. Switching the editor chat to GLM usually works while the upstream issue is open.

HTTP 400 Invalid schema for function '...' from a proxy or relay

This extension targets the OpenCode Go endpoints and the official GLM endpoints (BigModel Coding Plan, Z.ai, and the documented BigModel/Z.ai standard API). VS Code/Copilot generates the tool schemas verbatim from its own tool definitions and forwards them as-is. Third-party relays or proxies (e.g. New API, OneAPI) often enforce stricter OpenAI-schema validation than the official endpoint and reject schemas that contain default: null, certain anyOf/oneOf shapes, or other minor deviations — the most common symptom is Invalid schema for function 'get_errors': null is not of type "array".

This is not something this extension sanitizes, by design:

• We forward exactly what VS Code/Copilot produces, so any compatibility fix that works on the official endpoint is preserved.
• Maintaining per-relay quirks would create an ever-growing patch surface that can mask real upstream bugs.

If you hit this on a relay, the supported options are:

• Switch glm-copilot.baseUrl back to the OpenCode Go or official GLM endpoint (leave empty and use endpoint).
• Open a request dump with OpenCode: Open Request Dumps Folder and inspect the offending tool schema, then report the strict-validation bug to your relay.
• The error is also written to the OpenCode output channel — you can copy the full server response from there.

Compared to alternatives

Acknowledgements

This extension is a fork and rebrand of GLM for VS Code Copilot by ikaros, published under the MIT License. We thank the original author for the high-quality BYOK Copilot Chat provider implementation, vision proxy, and cost estimation infrastructure that make this OpenCode Go extension possible.

This project also references ideas and implementation patterns from Vizards/deepseek-v4-for-copilot, KiwiGaze/glm-for-copilot, and selfagency/z-models-vscode. Thanks to the original authors. Where applicable, redistribution and derivative work should preserve the original MIT License notices.

License

MIT