Three years of AI-crawler blocking — 2026-08

A permanent, citable page for this period's figure.

Three years of AI-crawler blocking · All releases

27.85%

Denominator: 377 conclusive domains. Coverage: 61.70% of the panel.

Provenance

This is why this page exists: the exact run that produced this figure, frozen alongside it rather than left to be inferred later.

Vintage1
Methodologyagents=2;protego=0.6.2
Collector9654a8f
Computed at

Every series value for this period

SeriesValue
Effective (named or blanket)29.71%
Blanket disallow (closed to every crawler)6.10%
Coverage61.70%
Unreadable robots.txt4.26%
Change since the previous reading1.10%
AI2Bot6.90%
AI2Bot-Dolma4.51%
Amazonbot10.34%
Applebot-Extended12.20%
Brightbot4.77%
Bytespider16.98%
CCBot17.77%
ChatGLM-Spider3.45%
ChatGPT-User13.00%
Claude-SearchBot11.14%
Claude-User10.88%
Claude-Web9.02%
ClaudeBot18.30%
DeepSeekBot5.04%
Devin3.71%
Diffbot11.94%
DuckAssistBot7.69%
GPTBot19.10%
Gemini-Deep-Research4.51%
Google-CloudVertexBot6.10%
Google-Extended16.18%
Google-NotebookLM3.71%
GoogleAgent-Mariner3.71%
ImagesiftBot8.75%
MistralAI-User5.84%
OAI-SearchBot11.94%
PanguBot5.84%
Perplexity-User8.22%
PerplexityBot15.65%
PhindBot2.92%
SBIntuitionsBot3.45%
TavilyBot3.45%
Timpibot7.69%
WrtnBot2.92%
YouBot8.22%
anthropic-ai9.55%
cohere-ai10.88%
cohere-training-data-crawler6.37%
iaskspider3.45%
meta-externalagent14.06%
meta-externalfetcher7.16%
meta-webindexer3.98%
omgili10.88%
omgilibot7.43%
webzio-extended6.37%

Restatements

This period has never been restated: the value above is the only one ever published for it.

Suggested citation

Three years of AI-crawler blocking, 2026-08: 27.85% (vintage 1). https://allanderek.github.io/tallyhouse/agent-accessibility-history/releases/2026-08/index.html

The two ledgers below carry this period's rows among every other period's; anything named for this period alone is listed with them.

Downloads

Every figure published on this site can be re-derived from these files. The two ledgers below are served as the exact bytes committed to the repository, not regenerated.

FileRowsSizeDescription
Headline ledger202.6 KBEvery headline figure ever published, for both indices, including superseded vintages and the reason each was restated. Served as the exact bytes committed to the repository.
Series ledger948130.2 KBEvery sub-series: the per-crawler rates, effective and blanket blocking, coverage, the unreadable share and the like-for-like change. Same vintage rules as the headline ledger, same exact bytes.
Balanced panel61112.5 KBThe domains measured by the historical index: those in the Tranco top 1000 at both ends of the span, with their rank at each end. Fixed across every period, which is what makes a change in that series a change in behaviour rather than in membership.