Shopping MCP Server

Channel3 Shopping

Shopping search across 100M+ products, with every retailer's offer and live price in one place — an MCP server with an interactive storefront UI on hosts that support it.

https://github.com/user-attachments/assets/59508319-aa1f-4462-afbe-52b64638ece3

• Transport: Streamable HTTP (protocol revision 2026-07-28, stateless)
• Endpoint: https://mcp.trychannel3.com/
• Tools: search_products, get_products, plus watch_product and unwatch_product when price and stock alerts are enabled
• Prompts: find-gift, price-check, find-dupes
• UI: results render in an interactive storefront (MCP Apps) on hosts that support it

Connect

One URL, no API key and no OAuth:

https://mcp.trychannel3.com/

Limits on the free tier are generous and sized for personal use. For unlimited usage and affiliate attribution, add an API key.

Claude Code

claude mcp add --transport http --scope user Channel3 https://mcp.trychannel3.com/

Claude web, Desktop, and mobile

Settings → Connectors → Add custom connector, then paste the endpoint URL. Claude connects from its own servers, so one connector covers every Claude surface including mobile.

Don't use claude_desktop_config.json for this: it only accepts stdio servers, and an entry with a url field is silently dropped along with the rest of mcpServers.

ChatGPT

Turn on developer mode under Settings → Security and login, then create an app under Settings → Plugins pointing at the endpoint URL, with authentication set to none.

Codex

codex mcp add Channel3 --url https://mcp.trychannel3.com/

Cursor and VS Code by hand

~/.cursor/mcp.json, or .cursor/mcp.json to scope it to one project:

{
  "mcpServers": {
    "Channel3": {
      "url": "https://mcp.trychannel3.com/"
    }
  }
}

.vscode/mcp.json, or code --add-mcp '{"name":"Channel3","type":"http","url":"https://mcp.trychannel3.com/"}' for the user profile:

{
  "servers": {
    "Channel3": {
      "type": "http",
      "url": "https://mcp.trychannel3.com/"
    }
  }
}

Any other client

Register the endpoint as a Streamable HTTP server; there is no SSE endpoint. It's stateless, so there's no session to keep alive, and clients on the 2026-07-28 revision can skip the initialize handshake entirely.

Price and Stock Alerts

watch_product subscribes a conversation to one variant's price and availability changes, including retailers starting or stopping selling it. A product with options needs a value for every option in selected_options, and the error lists any that are missing. When Channel3 detects a change, the conversation is woken through Wakeshift, even after it has gone idle.

How it fits together:

1. watch_product creates a Channel3 product subscription on this server's own account, then subscribes the conversation to the matching Wakeshift events (product.price.changed, product.availability.changed).
2. Channel3 posts signed webhooks to POST /webhooks/channel3. The server verifies the Standard Webhooks signature and emits the occurrence to Wakeshift, using the Channel3 event ID for deduplication.
3. When an event reaches no watchers, the server cancels its Channel3 subscription, once that subscription is over an hour old.

There's no sign-in, so each watch belongs to the conversation that made it. watch_product returns a watch_id, every alert repeats it, and unwatch_product takes it.

Setup:

wrangler secret put WAKESHIFT_KEY            # wst_… app key from the Wakeshift console
wrangler secret put CHANNEL3_WEBHOOK_SECRET  # whsec_… signing secret of the endpoint below

Waking uses @wakeshift/sdk, which needs @modelcontextprotocol/server 2.3 or later: on 2.0 to 2.2, Claude Code's background wait fails with Method not found and the conversation is never woken.

Add https://mcp.trychannel3.com/webhooks/channel3 as an endpoint in the Channel3 webhook dashboard of the account that owns DEFAULT_CHANNEL3_API_KEY, subscribed to offer.price.changed, offer.availability.changed, offer.created and offer.deleted. Without WAKESHIFT_KEY the watch tools aren't registered, and without both secrets the webhook route returns 404.

Free Tier and API Keys

Create an account at trychannel3.com, copy a key from the dashboard, and send it as an X-API-Key header. That lifts the free-tier rate limit and attributes affiliate clicks to your account.

• Cursor / VS Code: add "headers": { "X-API-Key": "<your-api-key>" } alongside url.
• Claude Code: append --header "X-API-Key: <your-api-key>" to the claude mcp add command.
• Claude connectors: enter the key under Request headers in the Add custom connector dialog. That section is a beta still rolling out.
• ChatGPT: developer-mode apps accept OAuth or no auth only, so there's no header field.
• OpenAI hosted MCP (Responses API mcp tool, HostedMCPTool): put the key in the tool's authorization field — the server accepts it as a bearer token.
• Codex: map the header to an env var in ~/.codex/config.toml so the key stays out of the file:

[mcp_servers.Channel3]
url = "https://mcp.trychannel3.com/"
env_http_headers = { "X-API-Key" = "CHANNEL3_API_KEY" }