Rank 348 in the Majestic Million · checked October 19, 2026
Does pbs.org block AI crawlers?
Yes, 3 of 17. As of October 19, 2026, pbs.org's robots.txt blocks GPTBot, CCBot and Bytespider from the whole site. It keeps the other 14 out of parts of the site. 4 of them are named in a group of their own; the others follow its rules for every crawler.
Its /llms.txt answered HTTP 502. Its homepage is 309,469 tokens of raw HTML, 68 as Markdown (0.0%) and 68 pruned for the question “What is pbs.org?”.
Each crawler, by its robots.txt rules
From https://www.pbs.org/robots.txt (3,502 bytes, 7 user-agent groups), parsed per RFC 9309. Blocked: no path allowed. Partly blocked: some paths disallowed. The rule counts are those of the groups that apply.
| Crawler | Operator | Verdict | Rules that apply | Disallow rules | Allow rules |
|---|---|---|---|---|---|
| GPTBot | OpenAI | Blocked | Its own group | 1 | 0 |
| ChatGPT-User | OpenAI | Partly blocked | Rules for all crawlers (*) | 91 | 0 |
| OAI-SearchBot | OpenAI | Partly blocked | Rules for all crawlers (*) | 91 | 0 |
| ClaudeBot | Anthropic | Partly blocked | Rules for all crawlers (*) | 91 | 0 |
| Claude-User | Anthropic | Partly blocked | Rules for all crawlers (*) | 91 | 0 |
| Claude-SearchBot | Anthropic | Partly blocked | Rules for all crawlers (*) | 91 | 0 |
| anthropic-ai | Anthropic | Partly blocked | Rules for all crawlers (*) | 91 | 0 |
| PerplexityBot | Perplexity | Partly blocked | Its own group | 1 | 1 |
| Perplexity-User | Perplexity | Partly blocked | Rules for all crawlers (*) | 91 | 0 |
| Google-Extended | Partly blocked | Rules for all crawlers (*) | 91 | 0 | |
| Applebot-Extended | Apple | Partly blocked | Rules for all crawlers (*) | 91 | 0 |
| CCBot | Common Crawl | Blocked | Its own group | 1 | 0 |
| Bytespider | ByteDance | Blocked | Its own group | 1 | 0 |
| Amazonbot | Amazon | Partly blocked | Rules for all crawlers (*) | 91 | 0 |
| meta-externalagent | Meta | Partly blocked | Rules for all crawlers (*) | 91 | 0 |
| cohere-ai | Cohere | Partly blocked | Rules for all crawlers (*) | 91 | 0 |
| Diffbot | Diffbot | Partly blocked | Rules for all crawlers (*) | 91 | 0 |
| ContextFetchBot (us) | ContextFetch | Partly blocked | Rules for all crawlers (*) | 91 | 0 |
Its homepage in tokens
https://www.pbs.org/, fetched once and converted locally with the ContextFetch engine. Tokens are characters divided by four, rounded up, the count the API reports in its X-Raw-Tokens and X-Output-Tokens headers.
| Group | Raw HTML | Markdown | Pruned |
|---|---|---|---|
| Tokens | 309,469 | 68 | 68 |
Read pbs.org through ContextFetch
GET /r/ returns a page as Markdown, with X-Raw-Tokens and X-Output-Tokens headers. Add ?q= and a question to get only the passages that answer it. No key needed for 25 requests a day; a free key has 2,500 credits. pbs.org's robots.txt partly blocks ContextFetchBot: our index and crawls skip what it disallows, and a page you ask for is fetched once on your behalf (see the bot page).
curl -si "https://api.contextfetch.dev/r/https://pbs.org/"curl -X POST https://api.contextfetch.dev/v1/keys/freeHow ContextFetchBot behaves · All sites and the method · Raw data
Give your agent the web
Your free key comes with 2,500 credits, no signup. One credit reads one page.