# docs.arbitrum.io

> Probe-verified (tier 2 of 3). Last checked 2026-08-23. 3 of 5 capability checks passed.

- host: docs.arbitrum.io
- url: https://docs.arbitrum.io/
- category: blockchain developer documentation
- type: documentation
- language: en

## Probe-verified · tier 2 of 3

Probed live on 2026-08-23 against rubric v1. 3 of 5 checks passed.

- PASS — Markdown negotiation
- PASS — Markdown twin at a predictable URL
- PASS — llms.txt
- fail — API catalog
- fail — MCP server answers

## 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.

- **read** — "Find quickstarts, guides, and reference docs for building dApps"
- **download** — "Nitro whitepaper" → `https://docs.arbitrum.io/nitro-whitepaper.pdf`

## Summary

Documentation providing guides and references for building dApps, bridging tokens, running nodes, and launching chains on Arbitrum.

## Context

32 sites in this index share the category "blockchain developer documentation"; 8 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