embark probe mispredicts the marker action for a chosen AGENTS.md that is a directory, a FIFO or an unreadable regular file: ahoy.EnsureMarker's dry run trusts classifyMarker, which folds every guarded-read error except a symlink into markerMissing, so the probe reports install (changed) while embark from, through installMarkerFileLocked, refuses the same file ('it could not be read') and reports skip. The person approves a plan that says AGENTS.md will be installed and the run then skips it; nothing wrong is written and the records land, but the plan was wrong. The embark marker tests ran the not-a-regular-file case through EmbarkFrom only.

embark probe mispredicts the marker action for a chosen AGENTS.md that is a directory, a FIFO or an unreadable regular file: ahoy.EnsureMarker's dry run trusts classifyMarker, which folds every guarded-read error except a symlink into markerMissing, so the probe reports install (changed) while embark from, through installMarkerFileLocked, refuses the same file ('it could not be read') and reports skip. The person approves a plan that says AGENTS.md will be installed and the run then skips it; nothing wrong is written and the records land, but the plan was wrong. The embark marker tests ran the not-a-regular-file case through EmbarkFrom only.

Grounds

• pursued: EmbarkProbe and EmbarkFrom give equal MarkerResults (skip, unchanged, same note) for a directory, a FIFO and a mode-000 AGENTS.md; TestEmbarkMarkerNeverWritesThroughALink failed on all three before the fix and passes after. A probe reporting install, or a note differing from from's, for any of them would show it wrong.