The decision has two conditions
Google says most sites do not need the tool. Its stated threshold requires both a considerable number of spammy, artificial, or low-quality links and a manual action, or a likely manual action, caused by those links. A scary score in a commercial crawler satisfies neither condition.
Start with provenance. Were the links bought, exchanged, automated, or created by a previous SEO to manipulate ranking? Does Search Console name unnatural links? Can the person or process that built them be identified and stopped? If the answer is merely “the domain rating looks low,” do not upload a destructive guess.
Removal comes before disavow in a manual-action case
For a confirmed unnatural-links manual action, Google asks the site owner to make a good-faith effort to remove violating links first. Document contacts and outcomes. The disavow list covers questionable URLs or domains that cannot be removed; it does not erase the need to fix the acquisition practice.
Blindly feeding an exported backlink list into the tool is particularly weak. Link reports are samples, third-party databases disagree, and authority metrics are vendor models rather than Google's classification.
Prepare the file precisely
The file is plain text encoded as UTF-8 or 7-bit ASCII and ends in .txt. Put one URL or domain instruction per line. To disavow a whole domain or subdomain, use the domain: prefix. Comments start with #. Google currently limits a file to 100,000 lines and 2MB, with a 2,048-character maximum URL length.
# Links that could not be removed after outreach
https://spam.example/page-with-link
domain:paid-network.exampleUploading a new list replaces the current list for that property. Export and preserve the existing file before changing it, then review the difference line by line.
Treat the upload as a consequential change
Google warns that incorrect use can harm Search performance. Processing also is not instant: the listed pages have to be recrawled and reprocessed, which can take weeks. Monitor the manual-action workflow and the affected query/page groups rather than watching a single sitewide visibility score.
If a manual action exists, connect the evidence to the broader manual-action remediation. If the report is clean, return to the ranking-loss investigation before assuming backlinks explain the graph.