No /llms.txt and no JSON-LD — the machine-readable description is missing

Found 2026-08-27 while checking whether pxxc.org is legible to non-browser fetchers. Fix lands in the private ~/pxx-website repo, not this checkout.

File this as a completion item, not a repair one. The audit came back better than expected and the passing results below are worth recording, because they tell whoever picks this up what NOT to go rebuild.

What already works — do not "fix" these

The SPA-shell check was the one that gated everything else, and it passes outright. Agent fetchers, unfurlers and search crawlers all get real content.

The result worth keeping

A small summarising model was pointed at the landing page and asked point-blank whether the page claims byte-identity with another compiler. It answered:

makes no claims about byte-identical output to other compilers, though it notes the project is "verified against gcc / fpc / cpython as oracles."

That is the exact outcome CLAUDE.md's claims-discipline section is written to produce, surviving the hard case — a compressor with every opportunity to drop the qualifier, which it could not do because the page never offered a pre-compressed version to grab. Whatever the landing page is doing here, keep doing it, and treat it as the standard the new files below must also meet.

The Limitations block ("about 2x slower than FPC, gcc, or CPython") is likewise an asset, not a liability: summarisers repeat it verbatim, and a page that states its own weakness reads as trustworthy. Do not soften it.

The two gaps

1. /llms.txt returns 404

Verified: curl -o /dev/null -w '%{http_code}' https://pxxc.org/llms.txt -> 404.

A stable machine-readable summary at a conventional path. This is the correct form of "make the project legible to agents" — the substance of that idea without any of the agent-forum-posting nonsense. Contents should be a short Markdown digest: what pxx is, the frontends, the targets, the honest limitations, and links to /docs/, /compliance/, /status/ and the GitHub repo.

Write it uncompressed. llms.txt exists specifically to be read by a summariser, so it is the file where a dropped qualifier does the most damage — the whole claims-discipline section of CLAUDE.md applies at full strength.

2. No JSON-LD structured data

Verified: no application/ld+json anywhere in the rendered head or body.

Add a SoftwareApplication or SoftwareSourceCode block: name, description, codeRepository (https://github.com/yoctobyte/pxx), programmingLanguage, license (MPL-2.0 for the core, per the repo's per-directory licensing), operatingSystem, and the CPU targets. This is what search and assistant surfaces read to answer "what is pxx" without fetching and re-summarising the prose every time.

What this does NOT fix

Neither file addresses the actual discovery gap: pxxc.org ranks for the string "pxx" and essentially nothing else. A cold search for the project returned Wikipedia and Fandom pages about other Pascal compilers as the competing results. Nobody searches "pxx" — they search "Pascal compiler ESP32", "self-hosting compiler", "compile C without libc". Getting into those is an authority-and-citations problem solved by things worth citing, not by on-site metadata. See [[feature-web-blog-bootstrap]].

Gate

/llms.txt returns 200 with the digest; JSON-LD validates; re-run the summariser check above and confirm the byte-identical discipline still holds in the answer.