# Double-hyphen dash Part of [The AI Tells Index](https://feedsquad.com/ai-tells). A tell signals low effort. It does not identify an author. Skilled writers produce every shape listed here, some of them daily, and automated detectors misread those writers for it at rates measured above 60 percent on non-native English prose. Nothing in this index proves that a machine wrote anything. Read an entry as one piece of evidence to weigh against the false-positive notes printed beside it. ## Facts - Id: double-hyphen-dash - Category: Formatting (formatting) - Subcategory: punctuation - Also known as: ASCII double hyphen in prose - Status: Active. Currently signals low-effort writing. - Severity: low - Evidence grade: community-observed (named by practitioners, no formal measurement exists) - Languages: en - Added: 2026-08-15 - Updated: 2026-08-17 - Page: https://feedsquad.com/ai-tells/double-hyphen-dash ## Description Two ASCII hyphens standing in for a dash in rendered text. The form survives when the composer does not convert it and nobody read the published version. ## Why it reads as machine-written It is the same pivot habit as the dash tell with the character unavailable. Two taxonomies record it separately, tropes.fyi as a named pattern and vale-ai-tells as a rule with its own repair message. Both write it narrowly, because a double hyphen at the front of a command-line flag is ordinary and correct. ## Detection Type: deterministic (a regular expression, run as written) Scope: sentence ECMAScript regular expression. The build validator compiles it and tests it against this entry's own specimens. ```regex (?:[A-Za-z]--[A-Za-z]|[A-Za-z] -- [A-Za-z]) ``` Flags: g ## Examples Constructed specimens. Written for this index. Never quoted from anyone's posts. ### Specimen 1 Before, exhibiting the tell: > The migration took two weeks--twice what we budgeted--and the lessons were worth the delay. Every migration teaches a team something about its own systems that no amount of planning surfaces in advance. What matters is that we came out of it better prepared for the next one. After, repaired: > The migration took two weeks against a one-week budget, and we never tested the rollback plan. That is why the Tuesday outage ran to 40 minutes instead of the five we told the board it would. Note: Figures in this repair are invented for the specimen. The tell is the pair of hyphens, not the emptiness around them. The earlier version of this specimen admitted a real failure with a real consequence, which made the entry look like it was policing punctuation in good writing. ## False positives Who legitimately writes this way. Writers who learned on typewriters and plain-text email type two hyphens for a dash by muscle memory and have done so since long before any of this. People who draft in Markdown or reStructuredText type it because their toolchain converts it on render. Technical documentation is full of it as a flag prefix, and a sentence about a flag will carry it correctly. Some editors convert on the fly and some do not, so one writer produces the artifact in one tool and not in another with identical source text. A reviewer should treat it as a note about the composer and the review pass, never about the author. ## Model attribution Unassigned. Neither taxonomy that lists the form attributes it to a model family, and no measurement of hyphen substitution by vendor exists in anything this project read. ## Platform notes - x: Plain-text bodies with no conversion step, so the two hyphens publish exactly as typed and read as leftover markup. ## Sources 1. tropes.fyi pattern directory https://tropes.fyi/directory (tier: community; accessed 2026-08-14) 2. vale-ai-tells, 111 machine-checkable rules https://github.com/tbhb/vale-ai-tells (tier: community; accessed 2026-08-14) ## Status history Ids are permanent. A retired tell keeps its id and its page. - 2026-08-15, Active: Active and cheap. Two independent taxonomies list the form, and the pattern is anchored to a letter on both sides so that command-line flags, which begin with a space and two hyphens, never register. Regex verified on 2026-08-15 against its own specimen and against three negatives including a flag and a chained flag argument. ## License CC BY 4.0. https://creativecommons.org/licenses/by/4.0/ Attribution: The AI Tells Index, feedsquad.com/ai-tells Reuse the data, including commercially. Keep the attribution line. --- Dataset version 1.0.0. Schema version 1. Part of [FeedSquad](https://feedsquad.com). Built by [Herman Foundry](https://hermanfoundry.com) from Levi, Finnish Lapland.