# isatty builtin docs (fish 3.6)

## Metadata

| Field | Value |
|---|---|
| Institute | Molodetz Institute — Research & Retrieval Division |
| Subject | shell-multiplexer-auto-attach |
| Document type | Source Citation Card |
| Tier | 2 |
| Source title | isatty - test if a file descriptor is a terminal |
| Source URL | https://fishshell.com/docs/3.6/cmds/isatty.html |
| Source type | vendor docs |
| Date researched | 2026-10-10 |
| Researched by | tai (agent), model: Claude Sonnet 5, on behalf of retoor |
| Research method | Search aggregator result listing (not independently opened or quoted) |
| Confidence | Not independently verified |
| Status | Active |

## Why it's here

Another version mirror of the isatty builtin doc page, used only to confirm cross-version stability in the Tier 1 dossier; not separately read.

## Changelog

| Date | Change |
|---|---|
| 2026-10-10 | Logged as consulted-but-not-analyzed. |