How to make Headroom proxy work with Cline + OpenRouter in VS Code (Windows)

[serjko]

Hi! Trying to get Headroom proxy working as a compression layer between Cline (VS Code extension) and OpenRouter, using GLM-5.2 as my model. Running on Windows.

Questions:

1. What is the correct Cline provider type and base URL format to route through Headroom's proxy to OpenRouter?
2. Should the API key field in Cline be the dummy key or the real OpenRouter key?
3. What model name format should I use — e.g. zhipuai/glm-5.2, openrouter/zhipuai/glm-5.2, or something else?

My setup:

• VS Code with Cline extension
• OpenRouter as API provider (model: zhipuai/glm-5.2)
• Headroom installed via pip in a venv
• Running proxy with: headroom proxy --port 8787 --backend openrouter

What happens when I start the proxy:
The proxy starts and prints this helpful guidance for OpenRouter users:

IMPORTANT for OpenRouter users:
  1. Set credentials: OPENROUTER_API_KEY
  2. Set a dummy Anthropic key: ANTHROPIC_API_KEY="sk-ant-dummy"
  3. Set base URL: ANTHROPIC_BASE_URL=http://127.0.0.1:8787
  4. Use model names: anthropic/claude-3.5-sonnet, openai/gpt-4o, etc.

I set OPENROUTER_API_KEY and ANTHROPIC_API_KEY as environment variables in the same PowerShell session before starting the proxy. But I'm not clear on how to apply step 3 and 4 to Cline specifically, since ANTHROPIC_BASE_URL is an environment variable that Claude Code reads natively — Cline uses a settings UI instead.

What I've tried in Cline settings:

Attempt 1 — OpenAI Compatible provider:

• Base URL: http://127.0.0.1:8787/v1
• API Key: sk-ant-dummy
• Model: openai/gpt-4o
• Result: 401 Incorrect API key provided

Attempt 2 — Anthropic provider:

• Base URL: http://127.0.0.1:8787
• API Key: sk-ant-dummy
• Result: 401 invalid x-api-key — and Cline's Anthropic provider doesn't allow a custom model name, so GLM-5.2 isn't usable this way

Any guidance appreciated — the proxy guidance message is helpful but written with Claude Code in mind and it's not clear how to translate it to Cline's settings UI. Thanks!

[highoncomputers]

The issue is that Cline's OpenAI Compatible provider and Headroom's OpenRouter backend need the right wiring. Here is the working configuration for Cline + OpenRouter via Headroom on Windows:

Cline Provider Settings (OpenAI Compatible):

• Base URL: http://127.0.0.1:8787/v1
• API Key: your real OPENROUTER_API_KEY (not the dummy key)
• Model: zhipuai/glm-5.2 (use the exact OpenRouter model slug)

Why the dummy key doesn't work: The ANTHROPIC_API_KEY=sk-ant-dummy env var is only relevant when Headroom routes requests in Anthropic wire format (for Claude Code which sends x-api-key). Cline's OpenAI Compatible provider sends requests in OpenAI wire format (/v1/chat/completions) with Authorization: Bearer <key>. Headroom forwards those to OpenRouter using your OPENROUTER_API_KEY. So you must put your real OpenRouter key in Cline's API key field.

For GLM-5.2 specifically: Use zhipuai/glm-5.2 as the model name in Cline. That's the OpenRouter model slug. Do not prefix it with openrouter/.

If you want to use Claude models via OpenRouter: Set the model to anthropic/claude-sonnet-4-6-20250515 (or whatever the current OpenRouter slug is).

Verification steps:

1. Start proxy: headroom proxy --port 8787 --backend openrouter
2. Ensure OPENROUTER_API_KEY is set in the same terminal session
3. In Cline, use OpenAI Compatible provider with:
   • Base URL: http://127.0.0.1:8787/v1
   • API Key: your OpenRouter key
   • Model: zhipuai/glm-5.2
4. Send a test message

The proxy's guidance message is written assuming Claude Code (which reads ANTHROPIC_BASE_URL from env vars). For Cline you translate it to the settings UI fields as shown above.

[serjko]

Good suggestion here. Alas, no luck so far. It looks like Headroom's OpenRouter backend expects Anthropic APIs in CLI mode. No combination of setting for Cline OpenAI Compatible model worked for me. I ended up switching to 9Router and it was a breeze to plug it into my Cline + OpenRouter setup. Bonus: It supports KLM and Headroom out of the box.

[Salim-alachaher]

Hi! I managed to identify the issue on Windows.

The important detail is that Cline's OpenAI Compatible provider sends requests to /v1/chat/completions, and Headroom routes that endpoint to OpenAI by default:

/v1/chat/completions → https://api.openai.com

So if Cline sends an OpenRouter key (sk-or-...) through Headroom without changing the backend URL, OpenAI rejects it with:

401 Incorrect API key provided

The working setup should be:

### 1. Start Headroom with OpenRouter as the OpenAI-compatible backend

In the same PowerShell session:

$env:OPENROUTER_API_KEY="sk-or-v1-YOUR_KEY"

headroom proxy --port 8787 --backend openrouter --openai-api-url "https://openrouter.ai/api"

The important part is:

--openai-api-url "https://openrouter.ai/api"

This prevents /v1/chat/completions from being sent to api.openai.com.

2. Cline provider

In Cline, use:

Provider: OpenAI Compatible
Base URL: http://127.0.0.1:8787/v1
API Key: your real OpenRouter API key
Model: zhipuai/glm-5.2

Do NOT use:

openrouter/zhipuai/glm-5.2

The model should use the exact OpenRouter slug:

zhipuai/glm-5.2
3. About the dummy Anthropic key

ANTHROPIC_API_KEY=sk-ant-dummy is only relevant when using Headroom through the Anthropic /v1/messages interface, which is what Claude Code uses.

For Cline's OpenAI Compatible provider, the request is:

/v1/chat/completions
Authorization: Bearer

So Cline should use the real OpenRouter API key, not sk-ant-dummy.

The resulting flow is:

Cline
↓
http://127.0.0.1:8787/v1
↓
Headroom
↓
https://openrouter.ai/api
↓
zhipuai/glm-5.2
↓
OpenRouter

One additional thing I noticed: Headroom's startup message is somewhat misleading for Cline because the ANTHROPIC_BASE_URL instructions are primarily aimed at Claude Code. For Cline, you need to translate that into the OpenAI Compatible provider settings above.

I also verified that Headroom itself was healthy on Windows (/health and /readyz both returned HTTP 200), so the key issue was the routing of /v1/chat/completions, not the proxy itself.