ucp.trychannel3.com. It speaks UCP (Universal Commerce Protocol), so shopping agents can search and look up products without learning a custom Channel3 API.
For most agents, MCP is the simpler approach. See MCP. Examples in this section show UCP CLI and curl side by side.
What you can do
| Action | Tool name |
|---|---|
| Search many stores at once | search_catalog |
| Look up by product ID or store URL | lookup_catalog, get_product |
com.trychannel3.catalog.global extension. See Extension reference.
Two URLs to know
| URL | What it does |
|---|---|
GET https://ucp.trychannel3.com/.well-known/ucp | Tells your agent what’s available (profile JSON) |
POST https://ucp.trychannel3.com/mcp | Where you call the tools |
Auth
Channel3 supports two tiers. See Authentication and Rate limits.| Tier | How | Good for |
|---|---|---|
| Anonymous | No API key | Quick tests, quickstart |
| Token | x-api-key header on each /mcp POST | Production traffic, affiliate variants[].url buy links |
@shopify/ucp-cli cannot send a Channel3 API key, so CLI commands always run as Anonymous on ucp.trychannel3.com. For Token tier, use curl or your own MCP client.
Same data as the REST API
UCP uses the same products asPOST /v1/search, POST /v1/lookup, and GET /v1/products/{ID}. Put the query in catalog; responses include products, pagination, and sometimes messages.
Where to start
Quickstart
Install the UCP CLI and run your first search. Quickstart
Add a key (curl / MCP clients)
Token tier for production traffic and monetizable links.
Authentication · Rate
limits
Search and lookup
Search · Lookup · Get
product