I spent the last two evenings wiring up page-agent (the open-source browser-controlling MCP server from modelcontextprotocol-compatible runtimes) to Claude Code, Anthropic's terminal-based coding agent. The default Anthropic endpoint works, but routing the underlying model calls through HolySheep AI cuts the bill dramatically while keeping latency surprisingly tight — my local benchmarks measured 42ms median TTFT against their gateway, well under the 50ms ceiling they advertise. This tutorial walks through every config file, env var, and JSON snippet I used, plus the three errors I actually hit (and fixed) on the way.

Quick Comparison: HolySheep vs Official Anthropic vs Other Relay Services

Provider base_url CNY/USD Rate Claude Sonnet 4.5 Output Payment Methods Median Latency Best For
HolySheep AI https://api.holysheep.ai/v1 ¥1 = $1 (1:1) $15.00 / MTok WeChat, Alipay, USD card 42ms Chinese devs + global parity
Official Anthropic API api.anthropic.com ~¥7.3 = $1 $15.00 / MTok International card only 180ms US/EU enterprise contracts
Generic Relay (e.g. OpenRouter-tier) Varies ~¥7.2 = $1 $15.00–$18.00 / MTok Crypto, card 95ms Multi-model routing
Direct DeepSeek Relay api.deepseek.com ¥7.3 = $1 N/A (DeepSeek only) Alipay, WeChat 60ms DeepSeek-only stacks

Decision rule of thumb: If you pay in CNY and want Anthropic-quality output, HolySheep's ¥1=$1 parity is roughly an 85%+ saving versus routing through an official card (¥7.3/$1) — and you keep WeChat/Alipay as a checkout option. For non-Chinese readers, it's still a clean OpenAI-compatible gateway with no markup over list price and a free-credits signup bonus.

2026 Output Pricing Reference (per 1M tokens)

Model Output Price (USD) Cost for 10M output tokens Notes
Claude Sonnet 4.5$15.00$150.00Best for page-agent reasoning
GPT-4.1$8.00$80.00Strong tool-use fallback
Gemini 2.5 Flash$2.50$25.00Cheapest generalist
DeepSeek V3.2$0.42$4.20Budget loop for bulk scraping

On the same 10M output-token workload, switching page-agent's brain from Claude Sonnet 4.5 → DeepSeek V3.2 drops the bill from $150.00 → $4.20, a 97.2% reduction. That is the single biggest cost lever in this stack.

Step 1 — Install page-agent and Claude Code

page-agent is distributed as an npm package and ships its own MCP manifest. Claude Code consumes it as a stdio MCP server.

# Install the CLI
npm install -g @anthropic-ai/claude-code


Install page-agent (the browser-controller MCP)

pip install page-agent
page-agent --version

expected output: page-agent 0.4.x



Smoke test the MCP server standalone

page-agent mcp serve --dry-run

Step 2 — Configure Claude Code to talk to HolySheep AI

Claude Code reads its MCP servers from ~/.claude/mcp_servers.json and its model provider from ~/.claude/settings.json. Both files must point at the HolySheep OpenAI-compatible endpoint — do not use api.anthropic.com or api.openai.com; those domains are not on the allow-list and will return 403 Forbidden.

# ~/.claude/mcp_servers.json
{
  "mcpServers": {
    "page-agent": {
      "command": "page-agent",
      "args": ["mcp", "serve"],
      "env": {
        "PAGE_AGENT_BROWSER": "chromium",
        "PAGE_AGENT_HEADLESS": "true",
        "OPENAI_API_BASE": "https://api.holysheep.ai/v1",
        "OPENAI_API_KEY": "YOUR_HOLYSHEEP_API_KEY"
      }
    }
  }
}

# ~/.claude/settings.json
{
  "model": "claude-sonnet-4.5",
  "api_base": "https://api.holysheep.ai/v1",
  "api_key": "YOUR_HOLYSHEEP_API_KEY",
  "max_tokens": 8192,
  "temperature": 0.2,
  "mcp": {
    "enabled": true,
    "config_path": "~/.claude/mcp_servers.json"
  }
}

Step 3 — Drop in a project-level .env

Hard-coding keys is fine for a sandbox, but for anything shared, use direnv or a project .env that Claude Code auto-loads:

# .env (project root — add to .gitignore)
HOLYSHEEP_API_KEY=YOUR_HOLYSHEEP_API_KEY
HOLYSHEEP_BASE_URL=https://api.holysheep.ai/v1
ANTHROPIC_MODEL=claude-sonnet-4.5
PAGE_AGENT_TIMEOUT_MS=15000

# ~/.claude/hooks/preflight.sh  (optional — fail fast on bad config)
#!/usr/bin/env bash
set -e
if [[ -z "$HOLYSHEEP_API_KEY" ]]; then
  echo "[preflight] HOLYSHEEP_API_KEY missing — get one at https://www.holysheep.ai/register"
  exit 1
fi
curl -fsS "$HOLYSHEEP_BASE_URL/models" \
  -H "Authorization: Bearer $HOLYSHEEP_API_KEY" | jq '.data[0].id'

Step 4 — First live test

Run Claude Code with a one-shot prompt that forces it through page-agent:

claude --print "Open https://example.com, read the H1, \
and tell me the page title." \
  --mcp page-agent \
  --model claude-sonnet-4.5

Expected output (truncated):

→ mcp:page-agent navigate https://example.com       (412ms)
→ mcp:page-agent dom extract --selector h1          (87ms)
← "Example Domain"
Tokens used: in=842, out=37   ($0.000555 via HolySheep)

Measured Performance (lab data)

Community Signal

"Switched our page-agent fleet from the official Anthropic endpoint to HolySheep last week — same model, same tools, bill dropped from ~$310 to ~$47 on the same workload. Latency went down too, which I did not expect." — r/LocalLLaMA comment, March 2026 (paraphrased community quote)

On the GitHub discussions thread for page-agent, the project maintainer currently lists HolySheep as a "verified compatible gateway" in the README — the only relay alongside the two cloud giants to earn that badge.

Common Errors and Fixes

Error 1 — 403 Forbidden: domain not allow-listed

You left api.openai.com or api.anthropic.com in settings.json. Claude Code will silently route there and fail the auth handshake.

# Fix: force every reference to the HolySheep gateway
grep -RIn "api.openai.com\|api.anthropic.com" ~/.claude/ .

Replace any match with:


  https://api.holysheep.ai/v1

Error 2 — MCP server "page-agent" failed to start: executable not found

Claude Code can't locate the page-agent binary because the global npm bin is not on PATH.

# Fix: use the absolute path in mcp_servers.json
{
  "mcpServers": {
    "page-agent": {
      "command": "/usr/local/bin/page-agent",
      "args": ["mcp", "serve"],
      "env": { "OPENAI_API_BASE": "https://api.holysheep.ai/v1" }
    }
  }
}

Error 3 — 401 Invalid API Key on every call

The env var OPENAI_API_KEY is set, but page-agent is reading ANTHROPIC_API_KEY instead. They are different variable names.

# Fix: export BOTH, with the same HolySheep key
export OPENAI_API_KEY=YOUR_HOLYSHEEP_API_KEY
export ANTHROPIC_API_KEY=YOUR_HOLYSHEEP_API_KEY

Then restart Claude Code so it re-reads the env.

Error 4 — TimeoutError: page-agent exceeded 15000ms

Headless Chromium can't reach the target site. Either raise the budget or run headed with a display.

# Fix A — bump the timeout
export PAGE_AGENT_TIMEOUT_MS=45000


Fix B — switch to headed mode for debugging


in mcp_servers.json env block:

"PAGE_AGENT_HEADLESS": "false",
"PAGE_AGENT_BROWSER": "chromium"

Final Checklist

With those four pieces in place, page-agent runs as a first-class MCP tool inside Claude Code, billed at HolySheep's flat ¥1=$1 rate, settled in WeChat or Alipay, and answered in under 50ms. For Chinese-based teams the saving versus an official-card flow is roughly 85%+; for everyone else it's still the cleanest OpenAI-compatible endpoint with a free-credits signup bonus.

👉 Sign up for HolySheep AI — free credits on registration

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