Agent Tax Index · v0-2026-07 · seeded panel
The Agent Tax Index measures what the web actually costs AI agents to read — in tokens, per domain, from live request receipts.
Measured across 35 requests to 9 domains via the Answer Gateway. Every number derives from request receipts — what each page cost in raw tokens versus what was delivered. Excerpt grounding is enforced by a deterministic verifier, so an answer is either backed by verbatim source spans or the request is recorded as not_found — never fabricated. USD figures use the reference rate in the footnote. This is v0: a disclosed measurement panel (the nine domains are declared, the runner and panel file are open on GitHub), the way SSL Labs and securityheaders.com began. It is not yet organic web-wide traffic.
Most expensive domains
Average raw tokens an agent would burn fetching these pages itself, versus what the gateway delivered. Each row links to its BotVisibility scan — the tax is the symptom, the scan is the cause.
| Domain | Category | Avg raw tokens | Avg tax avoided | Reduction |
|---|---|---|---|---|
| stripe.com | SaaS marketing | 241,995 | $0.24 | 100.0% |
| docs.stripe.com | Developer docs | 239,576 | $0.24 | 100.0% |
| en.wikipedia.org | Content publisher | 145,262 | $0.15 | 100.0% |
| docs.github.com | Developer docs | 78,016 | $0.078 | 99.9% |
| developer.mozilla.org | Developer docs | 51,051 | $0.051 | 99.9% |
| martinfowler.com | Content publisher | 16,733 | $0.017 | 99.3% |
| vercel.com | SaaS marketing | 10,844 | $0.011 | 99.9% |
Tax by category
Documentation and content-heavy sites cost agents far more tokens than sites that publish a machine-readable surface — and a lean SPA can be cheaper to read directly than to proxy. The scanner score is the dispatch signal.
How the web answers
When a site publishes llms.txt or negotiates Markdown, the gateway walks in the cheap door. When it doesn't, agents pay for full HTML distillation. 95.7% of answered requests required it. Most of the web doesn't offer a cheaper door.
Honest states
A scraper always “answers.” The gateway reports what actually happened.
Grounded answer returned, every excerpt verified verbatim against the source.
The answer was not on the page — the gateway said so instead of inventing one (common on JS-rendered SPAs).
Blocked by robots/no-AI policy, an HTTP error, or a timeout — with a stated reason.
Next edition: October 2026. The Agent Tax Index is published quarterly; each edition is snapshotted so the time series is frozen, not re-queried.
17 grounded answers fed the tax figures. The Agent Tax research · Answer Gateway docs · /api/index (JSON)
USD figures use the published Claude Haiku 4.5 input-token price ($1.00 per 1M tokens) as a reference rate. Panel v0-2026-07, measured from 2026-07-07.