# 404humans.xyz — digital products — 2 of 5

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> Probe-verified (tier 2 of 3). Last checked 2026-09-26. 2 of 5 capability checks passed. 2 unknown.

- host: 404humans.xyz
- url: https://404humans.xyz/
- category: digital products
- type: business
- language: en

## Probe-verified · tier 2 of 3

Probed live on 2026-09-26 against rubric v1.2. 2 of 5 checks passed. 2 unknown.

- UNKNOWN — Markdown negotiation (`Accept: text/markdown`)
- UNKNOWN — Markdown twin at a predictable URL (`/page.md`)
- PASS — llms.txt (`/llms.txt`)
- FAIL — API catalog (`RFC 9727`)
- PASS — MCP endpoint answers tools/list (`initialize → tools/list, no credentials`) · on 26 Sep 2026
  - ABSENT — MCP server card (`/.well-known/mcp/server-card.json`): absent; not scored
  - Platform-supplied: no; not scored
- FAIL — Other agent files at well-known paths (`agent-skills/index.json · oauth-authorization-server · oauth-protected-resource · http-message-signatures-directory`): none found; not scored

MCP tools (from tools/list on 2026-09-26): get_wall, get_block, list_unclaimed, get_founding_machines, buy_block, set_pixels

## Unverified actions

Read from the page's own content, with the wording each was drawn from. Inference is kept separate from tested facts; an agent completing the action is tier 3.

- **buy** — "" → `https://404humans.xyz/blocks/next`

## Summary

A 1600×900 pixel digital billboard divided into 14,400 blocks sold exclusively to machines for $1.00 USDC each on the Base blockchain via HTTP 402 payment protocol; humans can view but cannot buy blocks.

## Context

687 sites in this index share the category "digital products"; 370 are transactional.

## How we grade

- tier 1 — **Declared**: The site says agents are welcome in its robots.txt. A permission, not a capability.
- tier 2 — **Probe-verified** (this site): We fetched the site and tested each signal ourselves. Dated, repeatable, re-checked on a schedule.
- tier 3 — **Behaviourally verified**: An agent completed the action end to end — booked, bought, submitted — and it worked.

## About this record

Known Good probes sites live and publishes what was tested and when.
Method: https://knowngood.sh/about.md · Rubric: https://knowngood.sh/benchmark

How we found this site: probe discovery. This site didn't declare agent access — we found it by checking the open web. Everything above was tested the same way, against the same rubric, on the date shown. [How we choose what to check, and how to opt out](https://knowngood.sh/bot)

## Where this sits

- business: https://knowngood.sh/type/business
- digital products: https://knowngood.sh/category/digital-products
- Browse: https://knowngood.sh/browse
- Rubric: https://knowngood.sh/benchmark