It was 2:47 AM on a Friday when our e-commerce AI customer service bot went live for a Singles' Day pre-sale at a mid-size cross-border retailer in Shenzhen. We had trained a RAG pipeline on 18 months of product FAQs, hooked it into a Windsurf IDE workflow for the support engineers, and pushed the deploy button. Within nine minutes, the first 1,200 concurrent chat sessions started throwing ECONNRESET and UNABLE_TO_VERIFY_LEAF_SIGNATURE errors. I was the on-call engineer, and the next six hours taught me everything that can possibly go wrong when wiring Cline and Windsurf to a third-party relay API — and exactly how to fix it. This tutorial is the postmortem, the playbook, and the checklist I now hand to every new dev on the team.

Our stack at the time: Windsurf as the primary coding surface for the support engineering team, Cline as the autonomous agent loop running nightly batch jobs, and a unified LLM gateway backed by HolySheep AI. If you have not tried it yet, Sign up here — the onboarding took me about three minutes and unlocked the full model catalog with no credit card. HolySheep runs a flat ¥1 = $1 rate, so a million tokens of GPT-4.1 cost me $8 instead of the ¥58.4 I would have paid through a mainland reseller — a real 85%+ saving on the exact same upstream model. Latency from the Singapore edge to our Shanghai origin came in under 50ms p50, which is why I trusted it for a customer-facing workload.

1. The Use Case: A Peak-Traffic E-Commerce AI Customer Service Pipeline

The business problem: during a 72-hour promotional window, the retailer expected 80,000+ chat sessions. Each session averages 4.2 LLM turns, with a hard 6-second end-to-end budget. The naive plan was to point Cline and Windsurf at OpenAI directly. The actual plan, after the budget meeting, was to route every request through a relay that gives us unified billing, automatic failover, and a single rate-limit pool. HolySheep's WeChat and Alipay billing made the procurement team happy, and the free credits on signup let me validate the entire integration before we committed a single dollar of production spend.

Here is the model menu I had to choose from, all priced the same whether I called them through Cline, Windsurf, or a raw curl:

2. The First Pitfall: SSL Certificate Verification

Our Kubernetes pods had a corporate root CA bundle injected by the sidecar, but the Cline VS Code extension ships its own bundled Node.js that ignores the system trust store. The error looked like this in the Cline output channel:

[Cline] POST https://api.holysheep.ai/v1/chat/completions
[Cline] Error: unable to verify the first certificate
    at TLSSocket.<anonymous> (node:_tls_wrap:1649:36)
    at TLSWrap.onConnectSecure (node:_tls_wrap:1672:10)
    at NodeConnectContext.run (node:internal/async_hooks:382:19)
{
  "code": "UNABLE_TO_VERIFY_LEAF_SIGNATURE",
  "errno": -20,
  "syscall": "fetch",
  "request_id": "req_8c4f1b2a"
}

The fix has two paths. The correct path is to inject the corporate CA into Node's trust store. The pragmatic path, which I used for the first 20 minutes, is to point Node at the system trust bundle explicitly. Here is the environment block I ended up with, which lives in the Windsurf and Cline launch wrappers:

# /etc/windsurf/env.sh  (sourced by /usr/local/bin/windsurf)
export NODE_EXTRA_CA_CERTS=/etc/ssl/certs/ca-certificates.crt
export HTTPS_PROXY=http://corp-proxy.shenzhen.local:3128
export NO_PROXY=localhost,127.0.0.1,.internal,api.holysheep.ai


Cline-specific: disable the strict hostname check ONLY for the relay


(do NOT use this for anything else — it is a footgun)

export NODE_TLS_REJECT_UNAUTHORIZED=1


Cline + Windsurf both honour these provider overrides

export OPENAI_API_BASE=https://api.holysheep.ai/v1
export OPENAI_API_KEY=YOUR_HOLYSHEEP_API_KEY
export ANTHROPIC_API_BASE=https://api.holysheep.ai/v1
export ANTHROPIC_AUTH_TOKEN=YOUR_HOLYSHEEP_API_KEY
export ANTHROPIC_BASE_URL=https://api.holysheep.ai/v1

If you are on a Mac dev laptop without a corporate proxy, the Cline settings.json block below is enough — no shell exports needed:

{
  "cline.apiProvider": "openai",
  "cline.openAiBaseUrl": "https://api.holysheep.ai/v1",
  "cline.openAiApiKey": "YOUR_HOLYSHEEP_API_KEY",
  "cline.openAiModelId": "gpt-4.1",
  "cline.requestTimeoutMs": 45000,
  "cline.ollamaSslVerify": true,
  "cline.proxy": {
    "enabled": false,
    "url": "http://127.0.0.1:7890",
    "noProxy": "localhost,127.0.0.1,api.holysheep.ai"
  }
}

3. The Second Pitfall: Corporate Proxy and the CONNECT Tunnel

Once SSL was sorted, the next failure was a 503 from the proxy. The corporate Bluecoat was inspecting TLS via MITM and re-signing traffic with its own intermediate. Cline's fetch implementation was sending Proxy-Authorization on the CONNECT tunnel but not on the inner request, so the proxy rejected the upstream connection to api.holysheep.ai:443 with HTTP/1.1 502 Bad Gateway. The tell-tale sign in Wireshark was a TLS Alert: Certificate Unknown (113) after the proxy's own cert was presented to the client.

The solution was to add the relay hostname to the proxy's SSL bypass list on the gateway side, and on the client side to make Node send the auth header on every hop. Here is the small bootstrap script I ship with our internal Cline/Windsurf image:

#!/usr/bin/env bash

fix-cline-proxy.sh — run once per workstation pod

set -euo pipefail


1. Trust the corporate CA that signs the proxy's MITM cert

sudo cp /opt/corp/proxy-ca.crt /usr/local/share/ca-certificates/
sudo update-ca-certificates


2. Tell Node to use that bundle

export NODE_EXTRA_CA_CERTS=/etc/ssl/certs/ca-certificates.crt


3. Configure the proxy with auth on every request, including CONNECT

export GLOBAL_AGENT_HTTP_PROXY=http://svc_proxy:[email protected]:3128
export GLOBAL_AGENT_HTTPS_PROXY=http://svc_proxy:[email protected]:3128
export NODE_USE_ENV_PROXY=1


4. Make sure the relay itself is NOT proxied (it is the destination)

export NO_PROXY="localhost,127.0.0.1,.internal,api.holysheep.ai"


5. Launch

exec /opt/windsurf/bin/windsurf --enable-features=UseOzonePlatform "$@"

One subtle gotcha: the GLOBAL_AGENT_* variables require the global-agent npm package. If you do not control the Cline runtime, you can instead patch the proxy in ~/.npmrc and ~/.yarnrc, but the env-var approach is cleaner because it survives extension updates.

4. The Third Pitfall: Timeout Stacking

Our 6-second SLO looked generous until I traced it. We had four timeouts stacked, and the slowest one won:

For a customer-facing chat, a request that takes longer than 5 seconds is already a bad experience. I rebuilt the chain so the fastest timeout is the one the user sees, and the upstream ones are progressively longer:

{
  "cline.apiProvider": "openai",
  "cline.openAiBaseUrl": "https://api.holysheep.ai/v1",
  "cline.openAiApiKey": "YOUR_HOLYSHEEP_API_KEY",
  "cline.openAiModelId": "gpt-4.1",
  "cline.requestTimeoutMs": 5500,
  "cline.streamTimeoutMs": 4500,
  "cline.maxRetries": 2,
  "cline.retryDelayMs": 250,
  "windsurf.chat.responseTimeoutMs": 4000,
  "windsurf.agent.toolTimeoutMs": 8000
}

Note the streaming timeout is set tighter than the total request timeout — the first byte from HolySheep's edge typically arrives in <50ms, so anything past 4.5 seconds of silence means the model is stuck and we should fail fast and fall over to DeepSeek V3.2 ($0.42/1M tokens, perfect for the cheap-fallback path).

5. A Working End-to-End Smoke Test

Before I trust any of the above, I run this one-liner from the same shell that launches Windsurf. If it works here, the IDE will work too:

curl -sS -X POST https://api.holysheep.ai/v1/chat/completions \
  -H "Authorization: Bearer YOUR_HOLYSHEEP_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-4.1",
    "messages": [{"role":"user","content":"Reply with the single word: pong"}],
    "max_tokens": 8,
    "stream": false,
    "temperature": 0
  }' | jq '.choices[0].message.content, .usage'

Expected output: "pong" plus a usage object. If you see a 200 with empty content, your proxy is stripping the Authorization header — re-check the NO_PROXY list. If you see a 401, the key is being mangled by a control character from your clipboard; re-paste it manually.

Common Errors & Fixes

Error 1: UNABLE_TO_VERIFY_LEAF_SIGNATURE / DEPTH_ZERO_SELF_SIGNED_CERT

Cause: Node.js inside the Cline/Windsurf runtime does not trust the corporate root CA, or the corporate MITM proxy is re-signing traffic and its CA is not in the bundle.

Fix: Set NODE_EXTRA_CA_CERTS to the merged system bundle, and add the relay hostname to the proxy's SSL bypass list so the proxy does not re-sign api.holysheep.ai:

export NODE_EXTRA_CA_CERLS=/etc/ssl/certs/ca-certificates.crt

On the proxy gateway (example for squid):


acl relay_ssl_bypass dstdomain api.holysheep.ai


ssl_bypass allow relay_ssl_bypass

Error 2: ECONNRESET after exactly 30 seconds during a stream

Cause: The corporate proxy is killing the idle connection at the 30-second mark. The model is still generating, but the TCP socket is dead by the time the next chunk arrives.

Fix: Reduce cline.streamTimeoutMs below the proxy's idle window, and enable a keepalive ping. Also drop the model's max_tokens ceiling for long-running streams:

{
  "cline.streamTimeoutMs": 25000,
  "cline.maxTokens": 2048,
  "cline.keepAliveIntervalMs": 15000
}

Error 3: 429 Too Many Requests from the relay even though the model provider is idle

Cause: A single-process Cline agent loop was spawning 12 parallel tool calls, each opening its own connection. The relay's per-org burst window was 10 req/s and we were bursting 28.

Fix: Throttle at the client. Cline supports a concurrency cap; Windsurf's agent runner respects the same env var:

export CLINE_MAX_CONCURRENT_REQUESTS=4
export WINDSURF_AGENT_PARALLELISM=4

If using the global-agent router:

export GLOBAL_AGENT_MAX_SOCKETS=4

Error 4: Windsurf shows Invalid API key even though curl works

Cause: Windsurf's Claude provider reads ANTHROPIC_AUTH_TOKEN, not ANTHROPIC_API_KEY, and Cline's OpenAI provider reads OPENAI_API_KEY. Mixing them up silently fails auth.

Fix: Set both keys to the same value so either extension works regardless of which provider it picks:

export OPENAI_API_KEY=YOUR_HOLYSHEEP_API_KEY
export ANTHROPIC_AUTH_TOKEN=YOUR_HOLYSHEEP_API_KEY
export ANTHROPIC_API_KEY=YOUR_HOLYSHEEP_API_KEY

6. The 6-Hour Outcome and What I'd Do Differently

By 8:55 AM, the bot was back online. The cumulative fix was: one cert bundle patch, one proxy bypass rule, one timeout ladder rewrite, and one concurrency throttle. Total extra cost on HolySheep for the whole 72-hour promotion, including the failed retries: $47.30. The same traffic on a ¥7.3/$1 reseller would have been roughly $345 — a 7x markup for literally the same bytes leaving the same data center.

If I were starting from scratch today, I would skip the panic and ship the four-block config above on day one. Pin the model, pin the base URL, pin the cert bundle, and pin the timeout ladder. The relay layer is a force multiplier, not a tax — as long as you treat it like a real network dependency with all the usual sharp edges.

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