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Snap (snap install) — last resort, hand-off only (Band B, tier 8)

Permanent, system-wide install. Requires root. Ubuntu-centric but available on other distros via the snapd daemon. Last resort in the priority chain: prefer any higher-ranked manager that has the package.

The agent never runs this. Snap installs need sudo, and the agent's shell has neither privileges nor a TTY to answer a password prompt — the command would simply hang. Snap is always a hand-off: give the user the exact command, say why you can't run it, and continue from what they report back. There is no declarative equivalent; on a Nix or Guix host, a home.packages entry (declarative.md) is almost always the better answer.

Syntax — the commands you hand to the user

In Claude Code the user runs these in-session by prefixing !:

! sudo snap install <pkg>

! sudo snap install --classic <pkg>      # CLIs needing host access

Then they (or you, once installed) run it:

snap run <pkg> [<args>]

# Or, if the snap auto-aliases its binary onto PATH:
<pkg> <args>

Read-only snap subcommands (snap find, snap info, snap list) need no root — the agent may run those directly to check availability and confinement before proposing anything.

Key notes

  • Root is mandatory for install, refresh, revert, and remove. Every one of those is a hand-off. Never attempt them, never prompt for a password.
  • Many snaps are community-maintained with no upstream endorsement. Check upstream project docs before choosing Snap over another manager — e.g. ripgrep upstream explicitly discourages the snap.
  • Strict confinement (default) isolates the snap from the host. Classic confinement (--classic) gives the snap full host access and is required for many developer CLIs.
  • Snap binaries are often namespaced (snap-pkg.binary) but most publishers alias the plain name onto PATH.

Examples

Generic hand-off patterns (verify any specific package on https://snapcraft.io/ first — that check needs no root):

# Strict-confinement CLI
! sudo snap install <pkg>

# Classic-confinement CLI (e.g. editors, IDEs, compilers)
! sudo snap install --classic <pkg>

# A specific channel (edge, beta, candidate, stable)
! sudo snap install <pkg> --channel=edge

Once the user confirms the install landed, the agent can run it:

snap run <pkg> --version

Extras

Find and inspect without installing (no root — agent may run these)

snap find <term>
snap info <pkg>

Useful fields from snap info: channels:, confinement:, publisher:.

List installed snaps

snap list

Refresh (update) snaps — hand-off, needs root

! sudo snap refresh                 # all snaps
! sudo snap refresh <pkg>           # one snap
! sudo snap refresh <pkg> --channel=<channel>  # switch channels

Revert to a previous revision — hand-off, needs root

! sudo snap revert <pkg>

Lookup

Cleanup — hand-off, needs root

! sudo snap remove <pkg>

# Also remove saved snapshots of the snap's data
! sudo snap remove --purge <pkg>

Give the user the removal command at the same time you propose the install — Snap is permanent, system-wide, and the last-resort tier in the chain.