# Y Combinator llms.txt, public API and MCP server by batch group

One row per reachable Y Combinator domain (5,630 rows).

## Columns

- `domain`, `name`, `batch`, `year`: from the YC company list.
- `batch_group`: 2012-17, 2018-19, 2020-21, 2022-23, 2024 or 2025-26; empty for
  batches before 2012 or undated rows.
- `llms_txt`: 1 if /llms.txt returned a text file on 2026-09-04.
- `llms_generator`: the tool whose signature the file carries (Yoast SEO,
  Shopify, Wix, Webflow, Mintlify and others); empty when there is none.
- `llms_hand_written`: 1 if `llms_txt` is 1 and no generator signature was found.
- `mcp_registry`: 1 if the official MCP registry lists a server under the
  domain (namespace, remote URL or website URL).
- `in_sample`: 1 for the 900 domains in the API and MCP sample.
- `public_api`, `mcp_server`: 1 or 0 for sampled domains, empty otherwise.
- `mcp_platform_only`: 1 if the only MCP evidence was a Wix or Shopify
  template line; `mcp_server` is 0 for these.
- `api_evidence`, `mcp_evidence`: the rules that fired, with the URL or text
  matched.

## Denominators

llms.txt and registry shares use every reachable domain in the batch group
(909, 579, 1,044, 1,041, 571 and 1,261). API and MCP shares use the 150
sampled domains in each group.

## Licence

Data: CC BY 4.0, Installmap, 2026-09-23.
Source: Installmap, September 2026.