Answer engine
DuckAssistBot is operated by DuckDuckGo. Indexes you so an assistant can cite and link you. Blocking it removes you from AI answers.
DuckDuckGo runs it as an answer engine, which means it builds the index an assistant searches when somebody asks it a question. If your page is in that index you can be cited, quoted and linked in the answer. If it is not, you are not ranked lower — you are absent from the answer entirely, and no report anywhere will tell you so.
What blocking it costs you: Excluded from DuckDuckGo AI assist answers. You disappear from that assistant’s answers. Not ranked lower — absent, with no message anywhere telling you it happened.
These are two different strings and confusing them is why a rule that looks right does nothing. A robots.txt rule matches on the product token, case-insensitively, and ignores the rest of the user-agent header entirely.
| robots.txt token | DuckAssistBot |
|---|---|
| Operator | DuckDuckGo |
| Category | Answer engine |
| Full user agent | Mozilla/5.0 (compatible; DuckAssistBot/1.0; +https://duckduckgo.com/duckassistbot/) |
Paste this into robots.txt at the root of your domain.
User-agent: DuckAssistBot
Allow: /
Sitemap: https://axray.online/sitemap.xmlAn empty Disallow: and Allow: / mean the same thing to a crawler. What does not mean the same thing is having no rule at all: absence is permission by default, but it is permission nobody wrote down, and it survives only until somebody adds a blanket User-agent: * block without thinking about this crawler.
User-agent: DuckAssistBot
Disallow: /Before you paste that: excluded from DuckDuckGo AI assist answers. That is the cost, and it is paid silently — no error appears in your logs, no report tells you, and the traffic you lose was traffic you never saw arrive.
Deciding one crawler at a time is how a robots.txt ends up refusing things nobody meant to refuse. The free robots.txt generator asks the question once per category instead — train on me, cite me, fetch on demand, shop on my behalf — and writes the whole file for all 54 crawlers, naming what each refusal costs before you copy it.
Measured on 2026-09-06, by reading the robots.txt of 292 public websites and resolving each one against this crawler specifically.
| Verdict | Sites | Share |
|---|---|---|
| Blocked | 20 | 7% |
| Explicitly allowed | 218 | 75% |
| No rule either way | 54 | 18% |
No site is named, here or anywhere else on this domain. The count is the useful part; a league table of businesses that never asked to be measured is not.
The row worth reading twice is the last one. 54 of 292 sites have written no rule about DuckAssistBot at all, which means their position on it is an accident rather than a decision — whatever their User-agent: * block happens to say.
Reading your own robots.txt is not the same as knowing what a crawler concludes from it. Precedence between a User-agent: * group and a named one, the longest-match rule between overlapping paths, and a token you spelled slightly wrong all produce a file that looks correct and behaves otherwise.
npx axray-cli your-site.comThe scan resolves your file against all 54 crawlers on this list individually and reports which ones are allowed, blocked, or covered by nothing. It is free, needs no account, and installs nothing.
DuckAssistBot is an answer engine operated by DuckDuckGo: it builds the index an assistant searches when somebody asks it a question. If your page is in that index you can be cited, quoted and linked in the answer. If it is not, you are not ranked lower — you are absent from the answer entirely, and no report anywhere will tell you so.
Only if you are willing to pay what it costs. Excluded from DuckDuckGo AI assist answers. You disappear from that assistant’s answers. Not ranked lower — absent, with no message anywhere telling you it happened.
Mozilla/5.0 (compatible; DuckAssistBot/1.0; +https://duckduckgo.com/duckassistbot/) — and the robots.txt product token, which is what a rule actually matches on, is DuckAssistBot.
Scan your site with AXRAY. It resolves your robots.txt against 54 named AI crawlers individually rather than reporting one verdict for all of them, so it will tell you whether this specific crawler is allowed, blocked, or covered by no rule at all. It is free and needs no account.
OAI-SearchBot — OpenAIClaude-SearchBot — AnthropicPerplexityBot — PerplexityApplebot — Applemeta-webindexer — MetaAmazonbot — AmazonBravebot — BraveYouBot — You.comThe full reference: all 54 AI crawlers, and who blocks each one.
See which of these 54 crawlers your own site is blocking, and what each one costs you. One scan, no account.