I asked a chat app for an HTTP status code cheat sheet, then checked all 14 rows against MDN

Disclosure up front: I do marketing for HelloAI (tryhello.app), a chat app that can hand back editable documents and files. So this is a vendor-adjacent test, and I am showing the checking so you can judge it yourself.

I used a free HelloAI account (Free plan) and gave it one practical prompt:

Write me a one-page cheat sheet document I can keep: a table of 14 common HTTP status codes (200, 201, 204, 301, 302, 304, 400, 401, 403, 404, 409, 429, 500, 503) with columns: code, name, when an API should return it, and the most common misuse. Keep it tight.

It came back in about a minute as an editable document (it opens in a side editor, 443 words per the chat card, with a real table, not pasted text) instead of a chat reply. Then I read every row against the MDN pages for each code.

What matched MDN

All 14 rows were consistent with what MDN says. A few that are easy to get wrong:

• 204: the sheet's misuse is "sending a response body". MDN says a 204 must not include content. MDN 204
• 304: the sheet's misuse is returning it without a conditional request, or with a body. MDN: it answers a conditional GET/HEAD and must not contain a body. MDN 304
• 401 vs 403: the sheet says use 403 for an authenticated user without permission, and 401 for missing or invalid credentials. That matches MDN's description of both. MDN 401, MDN 403
• 404: "or the API chooses not to reveal it" matches MDN's note that servers may send 404 instead of 403 to hide a resource. MDN 403
• 409: conflict with the current state of the target resource. MDN 409
• 429 and 503: the sheet says to include retry guidance for 429 and that 503 is for temporary conditions. MDN agrees, and mentions the Retry-After header for both. MDN 429, MDN 503

What I would add (gaps, not errors)

• 401 has no mention that the response is sent with a WWW-Authenticate header. MDN says it is.
• 301 and 302 do not mention 308 and 307. MDN notes that user agents may switch POST to GET after a 301 or 302, and that 308 and 307 forbid changing the method. The sheet hints at this in the 302 row but does not name the fix.
• 404 does not mention 410 for resources that are permanently gone. MDN recommends it.
• 503 does not name Retry-After in the row text.

How far this goes

This is one prompt, one run, and I checked it against MDN, not against RFC 9110 line by line. I did not test whether the document exports cleanly to other formats. A table of well-known facts is also the easy case for any chat model, so the useful part for me was the format: a document with a table I could edit, rather than a wall of chat text. If you try it, run your own prompt and check it.

If you want to try the same prompt, HelloAI has a free plan (image generation is limited to 2 a day on it).