agentfs run error: failed to make mounts private: Permission denied (os error 13)

[RafaelZasas]

System Info:

OS: Ubuntu 26.04 LTS (Resolute Raccoon) x86_64
Kernel: Linux 7.0.0-15-generic
Shell: zsh 5.9
AgentFS verison: v0.6.4
AgentFS bin permissions:

❯ ls -l ~/.cargo/bin/agentfs
-rwxr-xr-x 1 <USER> <USER> 29731712 Mar 25 00:57 /home/<USER>/.cargo/bin/agentfs

FUSE info:

❯ fusermount -V
fusermount3 version: 3.18.2
❯ dpkg -l | grep fuse3
ii  fuse3                                      3.18.2-1                                   amd64        Filesystem in Userspace (3.x version)
ii  libfuse3-4:amd64                           3.18.2-1                                   amd64        Filesystem in Userspace (library) (3.x version)
❯ lsmod | grep fuse

Problem:

I just installed AgentFS and tried to run the example command to start a new session, but was met with an error baked into the help message, making it unclear at first whether it succeeded or failed.

This is the full cmd used and result:

❯ agentfs run --session update-documentation bash
Welcome to AgentFS!

The following directories are writable:

  - /home/PATH/TO/PROJECT/DIR/ (copy-on-write)
  - /home/<USER>/{.cache, .claude, .claude.json, .local, .npm}

🔒 Everything else is read-only.

To join this session from another terminal:

  agentfs run --session update-documentation <command>

Failed to make mounts private: Permission denied (os error 13)

Session: update-documentation

To resume this session:
  agentfs run --session update-documentation

To see what changed:
  agentfs diff update-documentation

The actual issue seems to be: Failed to make mounts private: Permission denied (os error 13)

I installed using the installer shell script from the docs.

One caveat is that I dont have rust or cargo installed:

❯ cargo --version
zsh: command not found: cargo
❯ rustup --version
zsh: command not found: rustup
❯ rustc --version --verbose
zsh: command not found: rustc

Although the docs didnt explicitly state that I need rust/cargo. I do also have .cargo/env exported in zshrc.

[LeMikaelF]

looks like a duplicate of #258