Card: precheck quick-start first

README.md

@@ -1,6 +1,6 @@
 ---
 license: cc-by-4.0
-pretty_name: "ARC: can AI shopping agents buy from these stores?"
+pretty_name: "ARC: can AI agents reach checkout at these stores?"
 language:
 - en
 tags:
@@ -31,7 +31,28 @@ configs:
   data_files: latest/protocol_matrix.parquet
 ---
 
-# 3,538 online stores checked: can AI shopping agents buy from them?
+## Quick start: precheck (free, no sign-in, CC BY 4.0)
+
+Before your agent tries a store, ask ARC whether agents can reach checkout there:
+
+```bash
+curl "https://www.arcreport.ai/api/precheck?url=https://allbirds.com"
+```
+
+Real response (trimmed, 14 Oct 2026):
+
+```json
+{"host":"allbirds.com","known":true,"reachable_checkout":true,
+ "rails":[{"name":"UCP","status":"valid"},{"name":"ACP","status":"not_found"},
+          {"name":"MCP","status":"yes"},{"name":"Checkout WebMCP","status":"detected"}],
+ "blockers":[],"confidence":"high","last_checked":"2026-10-13T09:47:13.000Z",
+ "stale":true,"source":"ARC (arcreport.ai)","licence":"CC BY 4.0"}
+```
+
+`reachable_checkout` is based on ARC's last saved check. It does not mean an agent completed checkout. Check `last_checked` and `stale` before relying on it. Contact: arcreport@mail.grokbot.com (ARC).
+
+
+# 3,538 online stores checked: can AI agents reach checkout?
 
 **Snapshot `2026-10-12`: 3,538 stores, checked 6 Oct 2026 to 12 Oct 2026.** The check finished for 3,497 of them (41 did not respond in time and are marked `not_tested`). Percentages below are of those 3,497.
 
@@ -125,14 +146,14 @@ No scraped page text or product copy, no model-written prose, no costs, no email
 
 Mirror of the official ARC open dataset at [arcreport.ai/data](https://www.arcreport.ai/data), updated after each weekly snapshot (Mondays). Files are byte-for-byte copies of ARC's published CSV and Parquet.
 
-**Current snapshot:** `2026-10-12` (snapshot date 2026-10-12, generated 2026-10-12 13:34 UTC, method `arc-method-2026.10`).
+**Current snapshot:** `2026-10-12.r2` (snapshot date 2026-10-12, generated 2026-10-12 20:37 UTC, method `arc-method-2026.10`, supersedes `2026-10-12`).
 
 | Config / table | Rows | What it holds |
 |---|---|---|
 | `store_answers` | 3,538 | Start here. One row per store in plain words: can AI agents find products and get a checkout link, what blocks them, a one-sentence verdict, top fix, and whether the answer is from the automated HTTP check or also the browser cart test. |
 | `stores` | 89 | Latest completed ARC Index result per store (browser cart test: score, personas that carted, failure label). |
 | `rails_checks` | 3,538 | Latest HTTP agent check per store domain (UCP profile, WebMCP, storefront MCP, catalog tool, cart link, checkout WebMCP). |
-| `adoption_history` | 29 | Weekly aggregate counts by source and metric (long format). |
+| `adoption_history` | 32 | Weekly aggregate counts by source and metric (long format). |
 | `personas` | 5 | The five ARC browser shopper personas (A to E) with legacy alias ids. |
 | `protocol_matrix` | 24 | Declared / Valid / Usable / Transacts counts per protocol with evidence labels. |
 
@@ -156,17 +177,27 @@ Or just download [`latest/store_answers.csv`](https://huggingface.co/datasets/Ar
 - `2026-10-09.r2` (generated 2026-10-09 15:54 UTC, method arc-method-2026.10)
 - `2026-10-09.r3` (generated 2026-10-09 16:03 UTC, method arc-method-2026.10)
 - `2026-10-12` (generated 2026-10-12 13:34 UTC, method arc-method-2026.10)
+- `2026-10-12.r2` (generated 2026-10-12 20:37 UTC, method arc-method-2026.10; adds `publishes_ucp_file`, `ucp_file_checked_at` to store_answers and `ucp_file` to rails_checks; adoption_history 29→32 rows)
+
+## Cite as
 
-### Citation
+**Cite as: ARC (arcreport.ai).** Please cite a dated version, not `latest/`.
+
+> ARC (arcreport.ai). *ARC Agent Commerce Index: can AI shopping agents buy from these stores?* Open dataset, snapshot 2026-10-12.r2, method arc-method-2026.10. CC-BY-4.0. https://www.arcreport.ai/data
+
+A machine-readable [`CITATION.cff`](https://www.arcreport.ai/CITATION.cff) is published with the data.
 
 ```bibtex
-@misc{arc_agent_commerce_index_2026,
-  title  = {ARC: can AI shopping agents buy from these stores? Open dataset},
-  author = {{ARC}},
-  year   = {2026},
-  note   = {Snapshot 2026-10-12, method arc-method-2026.10},
-  howpublished = {\url{https://huggingface.co/datasets/ArcReport/arc-agent-commerce}},
-  url    = {https://www.arcreport.ai/data},
-  license = {CC-BY-4.0}
+@misc{arc_agent_commerce_2026,
+  author       = {{ARC (arcreport.ai)}},
+  title        = {{ARC Agent Commerce Index: can AI shopping agents buy from these stores?}},
+  year         = {2026},
+  version      = {2026-10-12.r2},
+  note         = {Open dataset, method arc-method-2026.10. Licensed CC-BY-4.0},
+  publisher    = {ARC},
+  url          = {https://www.arcreport.ai/data},
+  howpublished = {\url{https://huggingface.co/datasets/ArcReport/arc-agent-commerce}}
 }
 ```
+
+When a Zenodo DOI exists, add `doi = {10.5281/zenodo.XXXXXXX}` to the entry.