# probe402 — The Machine Commerce Observatory

The independent measurement and evidence layer for machine commerce.

The Machine Commerce Observatory: independent readings of x402 and MPP endpoints — alive right now, quoting what, and how fast? Probed on a fixed clock under one published rubric, every reading traceable to a retained capture. Blocked and rate-limited are told apart from unreachable at capture time, so a defended endpoint is never reported as dead. Call before paying an unfamiliar endpoint, or to check whether one you use has repriced or rotated its payTo.

16118 endpoints are on the seed list: 16047 probed on a clock and 71 never contacted by policy. 14499 of them have been observed at least once, read from the collector's table of latest readings. Glossary: 65 entries.

## Pages

- Home: https://probe402.com/
- Publications: https://probe402.com/publications
- Answers: https://probe402.com/answers
- Method: https://probe402.com/method
- Record: https://probe402.com/coverage
- Integrity: https://probe402.com/chain
- Corrections: https://probe402.com/corrections
- Audit: https://probe402.com/audit
- About: https://probe402.com/about
- Glossary: https://probe402.com/glossary
- Rubric: https://probe402.com/rubric
- Facilitators: https://probe402.com/networks

## Machine surfaces

- Free grade (JSON by default): https://probe402.com/grade/{endpoint_id}
- Current reading, one object read: https://probe402.com/grade/{endpoint_id}/now
- Free grade by URL (the same grade looked up by the URL an agent is about to pay; a host URL lists that host's routes): https://probe402.com/grade?url={resource_url}
- MCP endpoint (JSON-RPC over POST; tool probe402_endpoint_history): https://probe402.com/mcp
- Open-source pre-payment check and head verifier (MCP server and CLI; reads these surfaces and nothing else): https://github.com/probe402/probe402-check
- OpenAPI: https://probe402.com/openapi.json
- Agent skill file: https://probe402.com/skill.md
- x402 discovery: https://probe402.com/.well-known/x402
- Sitemap: https://probe402.com/sitemap.xml

## Reports

Our own reports on the field we measure, each at one address.

- Machine Commerce Reality Index: #001 — August 2026: https://probe402.com/publications/pub_mcri_001
- Machine Commerce Conditions: MCC-001 — September 2026: https://probe402.com/publications/pub_mcc_001
- The questions those issues answer, one address each: https://probe402.com/answers

## Paid history (x402)

- 30 days, $0.005 per call: https://probe402.com/v1/history/30/:endpoint_id
- 180 days, $0.02 per call: https://probe402.com/v1/history/180/:endpoint_id
- the full archive, $0.05 per call: https://probe402.com/v1/history/full/:endpoint_id

Delivery: the recent window comes back inline in the answer. Deeper history is delivered as addresses — the answer's `delivery.bulk` block lists sealed-day manifests you fetch yourself from /chain/{date}, each with the chain digest to verify it. History is bulk by design: a graded answer sits on an agent's decision path, and that path cannot afford an inline archive fold. Tier depth and price are unchanged.

The grade is free. Money buys depth of history, never a better verdict.

probe402 measures every endpoint with the same published rubric, on the same clock, into the same public record. A paid engagement changes nothing in that record and is disclosed on the page it touches. Every claim here is a dated observation from our vantage, never a statement about what an endpoint is.