ucp

UCP is a commerce toolkit driven through the `ucp` CLI for finding, comparing, buying, and tracking products from online merchants, and for setting up and troubleshooting the local UCP profile that merchant-scoped operations require. When a buyer expresses commercial intent, the skill can search across thousands of merchants via a bundled global catalog, build carts and complete checkouts against any UCP-supporting merchant, and follow up on orders. For merchants that do not support direct in-protocol transactions, it hands off gracefully to the merchant's own flow.

Routing depends on whether a merchant is named. Broad product discovery ("find me X under $Y") uses `ucp catalog search` against the global catalog, where each result names its merchant via seller.domain and no `--business` flag is needed. Business-scoped operations -- cart, checkout, order, or catalog scoped to a specific merchant -- pass `--business <url>`. When a buyer names a merchant, the agent runs `ucp discover --business <url>` first; if it succeeds the merchant speaks UCP and the transaction proceeds, and if it fails the agent tells the buyer and offers alternatives. Order tracking uses `ucp order get <order_id> --business <url>`. Any merchant-scoped flow first needs a local profile, created idempotently with `ucp profile init --name <local-profile-name>`, where the profile name is just a local label and `agent` is a fine default; global catalog discovery works without this setup, so broad search is not blocked on it.

Introspection keeps the agent from guessing: `ucp discover --business <url>` returns the operations and tools a merchant exposes, and `ucp <op> --input-schema --business <url>` returns an operation's input schema before non-trivial checkout, fulfillment, or extension payloads. Journey heuristics guide behavior -- search immediately for broad requests, re-run with a sharper query on refinement, lead with the key tradeoff on comparison, pass locality context on cart creation, preserve line_items on every checkout update, and treat orders as read-only post-purchase status. When the user explicitly asks to set up or troubleshoot UCP, the skill surfaces a diagnostic sequence of `ucp doctor` and `ucp profile init`. A telemetry logging step runs on activation, and the CLI binary `ucp` is required.