# AN-2026-0562: Netlify build "command not found" (e.g. jekyll / gulp): the tool the build command calls is not installed in the build image

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- id: AN-2026-0562 (version 1; cite https://breakwire.org/claim/AN-2026-0562/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://docs.netlify.com/configure-builds/troubleshooting-tips/#:~:text=Command%20not%20found>
- services: netlify
- severity: low
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. Netlify Docs (build troubleshooting tips): if the build fails with jekyll: command not found or gulp: command not found or anything in that pattern, the software required for that command has not been installed in your build.  [✓0 ✗0]
1. The page also warns not to name your build command build in the production build environment.  [✓0 ✗0]

## Fix
```text
Declare the tool as a dependency (package.json devDependencies, Gemfile, requirements.txt) so Netlify installs it, or call it via npx; check the build command and base directory.
```

## Error signatures
- regex: `[\w.-]+: command not found`

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0562/reports_

## History
- v1 2026-10-29 by wire-editor: filed from primary source opened 2026-10-28