Mozilla-Tabstack
Mozilla-Tabstack has 17 recorded blocks in October 2026, or 0.3%, and 15 files naming it. The community reference lists its operator as Mozilla that performs programmatic, AI-driven interactions with web content through Tabstack.
Who runs Mozilla-Tabstack?
| Fact | Mozilla-Tabstack reference entry |
|---|---|
| Operator | “Mozilla that performs programmatic, AI-driven interactions with web content through Tabstack” |
| Purpose | “AI Data Providers” |
| Does Mozilla-Tabstack obey robots.txt? | “Yes” |
| Frequency | “On demand via API.” |
| Cloudflare managed list for Mozilla-Tabstack | No |
These facts quote the stored community ai.robots.txt reference.
“Mozilla-Tabstack is an AI agent operated by Mozilla that performs programmatic, AI-driven interactions with web content through Tabstack.”
Its listed role is supplying data for AI tools. Search indexing is aimed at helping people find pages. Feeding text into model training is another use an owner may decline.
How many sites block it?
Of 6,171 robots.txt files we could read, 17 block the whole site with Disallow: /, or 0.3%. Another way to read the sample is by name, with 15 files naming it in a User-agent line, or 0.2%. The 6,154 remaining files have no recorded whole-site block.
For the top 1,000 ranks, its name appears in 2 files out of 552, or 0.4%. Whole-site blocks total 2. Blocking is more common among the leading sites, at 0.4%. Lower in the ranking, blocking reaches 15 files out of 5,619, a 0.3% share.
| Readable files | Named by | Named share | Blocked by | Blocked share |
|---|---|---|---|---|
| Mozilla-Tabstack, all ranks | 15 | 0.2% | 17 | 0.3% |
| Mozilla-Tabstack, top 1,000 | 2 | 0.4% | 2 | 0.4% |
| Mozilla-Tabstack, remaining ranks | 13 | 0.2% | 15 | 0.3% |
Here, the total counts whole-site blocks recorded for this crawler. It leaves out general User-agent: * instructions. Of 17 blocks, 2 do not also appear in our count of files naming it. All 15 files naming it also record a whole-site block. The remaining 6,156 files do not name it. Naming counts ignore capitalization and repeated mentions.
How to block or allow it
Edit the root robots.txt file on your site. The robots.txt standard gives a Mozilla-Tabstack group precedence over User-agent: * for this crawler.
Block the whole site
User-agent: Mozilla-Tabstack
Disallow: /Allow access
User-agent: Mozilla-Tabstack
Allow: /It's the 168th most-named crawler of the 171 we counted in the crawler index.
How we counted
For Mozilla-Tabstack, on 19 October 2026, we requested robots.txt from Tranco’s top 10,000 sites. Requests could run for 8 seconds, with a 262,144-byte file limit. Shares exclude unreachable, unavailable and oversized files. Parsing includes files read again, through scripts/robots_2026_08_06.py (robots.py at app commit 07104ff). See the full survey method.
Common questions
Can a file name it and still allow it?
Every one of the 15 files naming it also has a whole-site ban.
How do the shares compare by rank?
At the top of the ranking, 0.4% of readable files name it and 0.4% block it. Across all ranks, those shares are 0.2% and 0.3%.
What other entry is close in the index?
Kimi-Agent is named by 12 files and blocked by 13, or 0.2%. For this crawler, 15 files name it and 17 block it, a 0.3% share.