agentrouter-opencode-proxy

A local proxy that lets Node.js AI coding clients use AgentRouter as an Anthropic-compatible LLM backend.

Get $150 in free credits

Sign up with this referral link and you get $150 in free credits to use on any model (Claude, GPT-4o, DeepSeek, Gemini, and more):

👉 https://agentrouter.org/register?aff=pP0u

Quickest setup: use the agent prompt

If you're already inside an AI coding agent (OpenCode, Claude Code, Cursor, Cline, etc.), the fastest way to get set up is to paste the prompt from AGENT_SETUP_PROMPT.md directly into your agent's chat.

The agent will:

Check prerequisites (Python 3.11+, git)
Clone this repo
Create the virtualenv and install dependencies
Ask for your API key and store it securely
Patch your opencode.json (or set env vars for other clients)
Start the proxy
Run both streaming and non-streaming end-to-end tests
Report results and tell you which model to select

No manual steps needed — the agent handles everything and confirms it works before finishing.

Supported clients

Client	Built on
OpenCode	Vercel AI SDK (`@ai-sdk/anthropic`)
Claude Code	`@anthropic-ai/sdk`
Cursor	Anthropic / OpenAI API
Cline	`@anthropic-ai/sdk`
Continue.dev	`@anthropic-ai/sdk`
Zed	Anthropic API
Aider	`litellm` (Python, OpenAI-compatible)
Any app using Vercel AI SDK	`@ai-sdk/anthropic`
Any app using `@anthropic-ai/sdk`	Node.js Anthropic SDK
Any app using LangChain.js	`@langchain/anthropic`

Point any of these at http://localhost:7187 and they'll work with AgentRouter.

Why this exists

AgentRouter is a Chinese API aggregator that provides cheap or free access to models like claude-opus-4-6, GPT-4o, DeepSeek, and others. It's fronted by an Aliyun WAF that fingerprints TLS handshakes at the connection level — not just bearer tokens.

Only a small allowlist of clients pass the check:

Claude Code
Codex CLI
Gemini CLI
RooCode / Kilocode / Qwen Code
The Python sync anthropic SDK (which those tools are built on)

Everything else — curl, Node.js fetch, Python httpx.AsyncClient, raw httpx.Client — gets:

{"error":{"message":"unauthorized client detected, contact support..."}}

This proxy runs locally on port 7187, receives requests from any Node.js AI SDK client, and re-issues them to AgentRouter using the Python sync anthropic SDK — which carries the correct TLS fingerprint.

Research trail

This solution was pieced together from several public issues and PRs. Here is the full chain of discovery in the order the clues surfaced.

1. The WAF allowlist is documented publicly

agentrouter-org/docs#21 — "Support ForgeCode as an official client (currently rejected with 'unauthorized client detected')"

This issue, opened by a ForgeCode contributor, contains the key finding:

AgentRouter is fronted by an Aliyun WAF that allowlists requests by client fingerprint, not just by bearer token. Generic API calls are rejected regardless of whether the API key is valid. Only the officially-supported clients and the Anthropic/OpenAI SDKs they're built on get past the check.

The same token does get past client authentication when used with the official Claude Code client configured with ANTHROPIC_BASE_URL=https://agentrouter.org/.

This was the first public confirmation that routing through the Anthropic SDK bypasses the WAF.

2. OpenCode hits the same wall

anomalyco/opencode#5060 — "Agentrouter not working"

An OpenCode user reports the identical unauthorized client detected error after connecting with a valid AgentRouter key. The issue confirms that OpenCode's Node.js AI SDK cannot communicate with AgentRouter directly — the same WAF fingerprint block documented in #1.

3. First working fix: sync Anthropic SDK

yowanda/Reckora#67 — "fix(reasoning): route AgentRouter through Anthropic SDK so its WAF allowlist accepts requests"

The Reckora project (a Python app) hit the same wall and documented the fix in detail:

Switch the AgentRouter dispatch path from AsyncOpenAI (chat-completions shape) to AsyncAnthropic (messages shape) against the Anthropic-compatible /v1/messages route. This is the same wire shape Claude Code uses, so AgentRouter's WAF accepts our requests as a "Claude Code-shaped client".

Live verification from their production VPS:

OpenAI SDK   → /v1/chat/completions  → 401 unauthorized client detected
Anthropic SDK → /v1/messages         → 200 / 503 (downstream pool routing — WAF passed)

The 503 "no available channel" is a capacity issue on AgentRouter's pool, not a code bug. It means the WAF check passed.

4. Base URL trap: `/v1` double-prefix

yowanda/Reckora#68 — "fix(reasoning): coerce stale AgentRouter base URL to root so Anthropic SDK lands on /v1/messages"

Immediately after #67 shipped, a new failure:

The Anthropic SDK appends /v1/messages to whatever base_url it's given. If base_url is https://agentrouter.org/v1, the runtime URL becomes /v1/v1/messages and AgentRouter returns 404 "Invalid URL".

Fix: set base_url to https://agentrouter.org (no /v1 suffix). The SDK constructs the correct /v1/messages path on its own.

This applies directly to our opencode.json config — baseURL must be http://localhost:7187 with no path, and the proxy's TARGET must be https://agentrouter.org with no path.

5. Async SDK is also blocked — sync-in-thread required

yowanda/Reckora#69 — "fix(reasoning): use sync Anthropic SDK in asyncio.to_thread (AgentRouter WAF rejects async-httpx fingerprint)"

After #68 deployed, another 401 — even though the Anthropic SDK was being used:

Live A/B inside the production container, same key, same anthropic==0.100.0:
Anthropic(...).messages.create(...)       → 503  (WAF passed, downstream pool routing)
AsyncAnthropic(...).messages.create(...)  → 401  "unauthorized client detected"
The differentiator is the async-httpx (AsyncHTTPTransport / anyio-backed) TLS handshake itself; AgentRouter's Aliyun WAF fingerprints at the connection level and only the sync httpx handshake is on the allowlist.

Fix: use anthropic.Anthropic (sync) and call messages.create inside asyncio.to_thread so the event loop stays non-blocking but the wire request uses the sync httpx TLS stack.

This is the exact architecture of proxy.py in this repo.

Summary of the discovery chain

Step	Finding	Source
1	WAF blocks by TLS fingerprint, not just bearer token	agentrouter-org/docs#21
2	OpenCode (Node.js) is blocked the same way	anomalyco/opencode#5060
3	Python sync `Anthropic` SDK passes the WAF	yowanda/Reckora#67
4	`base_url` must not include `/v1` — SDK appends it	yowanda/Reckora#68
5	`AsyncAnthropic` is also blocked — must use sync SDK in thread	yowanda/Reckora#69
6	AgentRouter injects `billing_summary` SSE events that break OpenCode's parser	Discovered live during setup
7	`thinking` and `output_config` fields trigger AgentRouter's content filter	Discovered live during setup
8	OpenCode AI SDK calls `/messages` not `/v1/messages`	Discovered live during setup
9	Aliyun WAF returns 405 HTML block when request body contains PHP tags (`<?php`) or shell tokens	Discovered live during setup

Additional quirks discovered during setup

Issue	Fix
WAF also blocks `httpx.AsyncClient` and raw `httpx.Client`	Must use `anthropic.Anthropic` (sync), not `AsyncAnthropic` or bare httpx
AgentRouter injects `billing_summary` SSE events	Proxy filters them — OpenCode's Zod parser rejects unknown event types
Aliyun WAF 405 blocks on code tokens (`<?php`, `system(`, etc.)	Proxy transparently neutralizes these using invisible zero-width spaces (`\u200b`)
OpenCode AI SDK calls `/messages` (no `/v1` prefix)	Proxy mounts on both `/messages` and `/v1/messages`
`GET /v1/models` is also WAF-blocked	Proxy returns a local stub model list instead

Manual setup

Prefer to do it yourself? Follow these steps.

Prerequisites

Python 3.11+
An AgentRouter account with an API key (sk-... from agentrouter.org/console/token)
One of the supported clients above

1. Clone the repo

git clone https://github.com/Goodnessmbakara/agentrouter-opencode-proxy
cd agentrouter-opencode-proxy

2. Create the virtualenv and install dependencies

python3 -m venv .venv
.venv/bin/pip install fastapi "uvicorn[standard]" httpx anthropic

3. Store your API key

mkdir -p ~/.config/opencode/api_keys
echo 'sk-YOUR_KEY_HERE' > ~/.config/opencode/api_keys/AGENT_ROUTER_API_KEY
chmod 600 ~/.config/opencode/api_keys/AGENT_ROUTER_API_KEY

Or set it as an environment variable instead:

export AGENTROUTER_API_KEY=sk-YOUR_KEY_HERE

4. Configure your client

OpenCode

Add this to ~/.config/opencode/opencode.json:

{
  "provider": {
    "anthropic": {
      "options": {
        "apiKey": "{file:~/.config/opencode/api_keys/AGENT_ROUTER_API_KEY}",
        "baseURL": "http://localhost:7187"
      },
      "whitelist": ["claude-opus-4-6"]
    }
  }
}

Claude Code / Cline / Continue / any Anthropic-compatible client

export ANTHROPIC_BASE_URL=http://localhost:7187
export ANTHROPIC_API_KEY=sk-YOUR_KEY_HERE

Cursor / any OpenAI-compatible client

Set the base URL to http://localhost:7187 and the API key to your AgentRouter key in the client's settings.

Note: Only claude-opus-4-6 had reliable capacity on AgentRouter at the time of writing. Other models return 503 no available channel. Check the AgentRouter model list for current availability.

5. Start the proxy

bash start.sh
# or directly:
.venv/bin/python proxy.py

You should see:

AgentRouter proxy  →  https://agentrouter.org
Listening on http://127.0.0.1:7187

6. Start your client

Select anthropic/claude-opus-4-6 (or the equivalent model name in your client).

Auto-start on macOS (optional)

cat > ~/Library/LaunchAgents/org.agentrouter.proxy.plist << EOF
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key>
  <string>org.agentrouter.proxy</string>
  <key>ProgramArguments</key>
  <array>
    <string>$(pwd)/.venv/bin/python</string>
    <string>$(pwd)/proxy.py</string>
  </array>
  <key>RunAtLoad</key>
  <true/>
  <key>KeepAlive</key>
  <true/>
  <key>StandardOutPath</key>
  <string>/tmp/agentrouter-proxy.log</string>
  <key>StandardErrorPath</key>
  <string>/tmp/agentrouter-proxy.log</string>
</dict>
</plist>
EOF

launchctl load ~/Library/LaunchAgents/org.agentrouter.proxy.plist

Testing the proxy directly

# Non-streaming
curl -s http://localhost:7187/messages \
  -H "content-type: application/json" \
  -d '{"model":"claude-opus-4-6","max_tokens":50,"messages":[{"role":"user","content":"hello"}]}'

# Streaming
curl -s http://localhost:7187/messages \
  -H "content-type: application/json" \
  -d '{"model":"claude-opus-4-6","max_tokens":50,"stream":true,"messages":[{"role":"user","content":"hello"}]}'

A successful response means the WAF check passed and the model has capacity.

Troubleshooting

Error	Cause	Fix
`unauthorized client detected`	WAF blocked — not using proxy	Ensure your client points to `http://localhost:7187`, not agentrouter.org directly
`503 no available channel`	Model pool exhausted on agentrouter.org	Try another model or wait and retry
`405 / AI_APICallError` ("很抱歉，由于您访问的URL有可能对网站造成安全威胁...")	Aliyun WAF blocked request body containing code tokens (`<?php`, shell functions)	The proxy automatically neutralizes these using invisible zero-width spaces (`\u200b`); make sure proxy is updated
`content-blocked`	AgentRouter upstream content filter triggered	Avoid triggering sensitive keywords or try another model family
`Not Found` from proxy	Wrong path	Proxy handles `/messages` and `/v1/messages` — ensure `baseURL` has no path suffix
Port 7187 already in use	Old proxy still running	`lsof -ti :7187 \| xargs kill -9`

Name		Name	Last commit message	Last commit date
.gitignore		.gitignore
AGENT_SETUP_PROMPT.md		AGENT_SETUP_PROMPT.md
CONTRIBUTING.md		CONTRIBUTING.md
Dockerfile		Dockerfile
README.md		README.md
docker-compose.yml		docker-compose.yml
proxy.py		proxy.py
pyproject.toml		pyproject.toml
requirements.txt		requirements.txt
start.sh		start.sh

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Repository files navigation

agentrouter-opencode-proxy

Get $150 in free credits

Quickest setup: use the agent prompt

Supported clients

Why this exists

Research trail

1. The WAF allowlist is documented publicly

2. OpenCode hits the same wall

3. First working fix: sync Anthropic SDK

4. Base URL trap: `/v1` double-prefix

5. Async SDK is also blocked — sync-in-thread required

Summary of the discovery chain

Additional quirks discovered during setup

Manual setup

Prerequisites

1. Clone the repo

2. Create the virtualenv and install dependencies

3. Store your API key

4. Configure your client

OpenCode

Claude Code / Cline / Continue / any Anthropic-compatible client

Cursor / any OpenAI-compatible client

5. Start the proxy

6. Start your client

Auto-start on macOS (optional)

Testing the proxy directly

Troubleshooting

About

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Repository files navigation

agentrouter-opencode-proxy

Get $150 in free credits

Quickest setup: use the agent prompt

Supported clients

Why this exists

Research trail

1. The WAF allowlist is documented publicly

2. OpenCode hits the same wall

3. First working fix: sync Anthropic SDK

4. Base URL trap: /v1 double-prefix

5. Async SDK is also blocked — sync-in-thread required

Summary of the discovery chain

Additional quirks discovered during setup

Manual setup

Prerequisites

1. Clone the repo

2. Create the virtualenv and install dependencies

3. Store your API key

4. Configure your client

OpenCode

Claude Code / Cline / Continue / any Anthropic-compatible client

Cursor / any OpenAI-compatible client

5. Start the proxy

6. Start your client

Auto-start on macOS (optional)

Testing the proxy directly

Troubleshooting

About

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Contributing

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4. Base URL trap: `/v1` double-prefix