headquarter/openspec/changes/fix-pi-container-mount-permissions/change.md

Fix pi container repo mount and npm update permissions

Problem

After implementing configurable tool container home directories, new pi-agent containers still bind-mount the git repository at /workspace instead of under /home/user/{repo_name}. In addition, users cannot run npm update -g @earendil-works/pi-coding-agent inside the container because the global npm prefix (/usr/lib/node_modules) is owned by root.

Root cause

1. The built-in pi-agent manifest in tool_definition_manifests still declares an explicit repo mount with "target": "/workspace" and "working_dir": "/workspace". This masks the generated /workspace → /home/user/{repo} compatibility symlink.
2. manifest_compiler.py does not substitute the instance-specific {{WORKSPACE_NAME}} placeholder in explicit mount targets, and instance_service.py does not pass WORKSPACE_NAME/REPO_NAME to compile_compose for manifest-based tools.
3. The generated entrypoint hardcodes the literal string {{WORKSPACE_NAME}} as the symlink target.
4. npm_global packages are installed with RUN npm install -g ... as root into the system npm prefix, so the non-root container user cannot update them.
5. Once the repo mount moves out of /workspace, the generated /workspace compatibility symlink is created in the image as root. The non-root entrypoint cannot replace it (write permission is required on /), so container startup fails.
6. Older images baked a literal {{WORKSPACE_NAME}} directory into /home/user, which survives alongside the real repo-named mount directory.

Fix

1. Remove the compose-level user: 0:0 override from manifest_compiler.py. The Dockerfile intentionally omits USER so the entrypoint can start as root, fix mount ownership, and drop privileges to the container user internally. Pinning user: 0:0 in the compose service forces docker exec sessions to run as root even after the entrypoint drops privileges.
2. Pass the manifest-declared container user into terminal sessions so docker exec is invoked with --user <user>. This makes WebSocket terminal sessions run as the same non-root user as the main container process.
3. Add an Alembic data migration that updates the built-in pi-agent manifest:
   • Change the repo mount target to ~/{{WORKSPACE_NAME}}.
   • Keep runtime.working_dir as /workspace (the compatibility symlink).
   • Update the startup script to chown the real mount path ($HOME/$WORKSPACE_NAME).
4. Update manifest_compiler.py:
   • Substitute {{WORKSPACE_NAME}} in mount targets in compile_compose.
   • Pass WORKSPACE_NAME as a container environment variable.
   • Generate the entrypoint symlink from the runtime WORKSPACE_NAME environment variable.
   • Install npm_global packages into a user-writable prefix ({home_dir}/.npm-global) and add it to PATH.
   • Use sudo or root to create the /workspace compatibility symlink, because / is owned by root and the non-root entrypoint cannot replace a root-owned symlink.
   • Start the container as root and drop privileges to the container user inside the entrypoint via su.
   • Do not create mount target directories or the /workspace symlink in the image when they depend on the runtime {{WORKSPACE_NAME}} placeholder.
   • Remove any stale literal {{WORKSPACE_NAME}} directory left over from older images at container startup.
5. Update instance_service.py to pass REPO_NAME and WORKSPACE_NAME into manifest compilation.
6. Remove the explicit repo mount from the built-in pi-agent manifest so the repo mount is synthesized by compile_compose rather than depending on tool config. Add a follow-up Alembic data migration that strips the source_type: repo mount from the manifest.
7. Add _get_repository_mount_name() helper. When the instance is bound to a workspace, the helper returns the basename of workspace.path. For legacy repo-only instances it falls back to parsing the remote URL like git clone would, then to the user-provided repository name.
8. Switch workspace storage layout to /data/working-copies/{workspace_id}/{repo_name}/ so git clone creates the repo-named directory naturally, making workspace.path.basename the correct container mount name. This replaces the previous /data/working-copies/{repo_id}/{workspace_name}/ layout.
9. Update unit tests for the new behavior.

Affected files

• apps/api/alembic/versions/2026_06_14_182955_fix_pi_agent_home_directory_mount.py
• apps/api/alembic/versions/2026_06_15_090500_remove_pi_agent_explicit_repo_mount.py
• apps/api/src/services/build/manifest_compiler.py
• apps/api/src/services/terminal/terminal_session.py
• apps/api/src/services/terminal/terminal_manager.py
• apps/api/src/api/system/terminal.py
• apps/api/src/services/shared/workspace_manager.py
• apps/api/src/services/tool/instance_service.py
• apps/api/tests/unit/test_manifest_compiler.py
• apps/api/tests/unit/test_terminal_session.py
• apps/api/tests/unit/test_instance_service.py
• apps/api/tests/unit/test_alembic_migrations.py

Verification

• pytest apps/api/tests/unit/test_manifest_compiler.py
• pytest apps/api/tests/unit/test_terminal_session.py
• pytest apps/api/tests/unit/test_alembic_migrations.py
• ruff, mypy, npm run typecheck, npm run lint