## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work
> - The run layer must move project context into the sandbox that
executes the agent
> - Local sandboxes already stage referenced projects for @-mentions
> - Remote confined sandboxes dropped the whole referenced set, so the
agent lost needed files and paths
> - This pull request keeps the confined sandbox transport aligned with
the local behavior for referenced projects
> - It does this behind a remote-only flag that defaults on, while SSH
keeps the old drop-only path
> - The benefit is that remote runs can read the same referenced project
context that local runs already provide
## Linked Issues or Issue Description
**Subsystem affected**
Cross-cutting. This change touches server orchestration, sandbox
transport, and observability.
**Problem or motivation**
A run can @-mention another project. Local targets stage each referenced
project and give the agent a path. Remote confined sandboxes dropped the
full referenced set, so the agent could not read those project files or
paths.
**Proposed solution**
Enable referenced-project sync for the confined sandbox transport behind
`PAPERCLIP_MULTI_PROJECT_WORKSPACE_SYNC_REMOTE`, which defaults on. Keep
the SSH transport out of scope and keep it dropping referenced projects.
Repoint each referenced workspace hint at its staged
`project-<projectId>` sandbox directory. Publish
`PAPERCLIP_WORKSPACES_JSON` on the confined sandbox lane. Count each
per-project remote staging failure as a `staging` failure in the
requested-vs-synced metrics.
**Alternatives considered**
Keep the remote path drop-only. That keeps the gap open. Move the change
into SSH too. That expands scope beyond the target transport and adds
risk.
**Roadmap alignment**
No matching item in `ROADMAP.md` showed up in this review.
**Additional context**
The change lands in three commits. The first commit opens the gate for
the confined sandbox transport. The second commit repoints the workspace
hints and publishes the workspace map. The third commit records
per-project staging failure data.
## What Changed
- Opened remote referenced-project sync for the confined sandbox
transport behind `PAPERCLIP_MULTI_PROJECT_WORKSPACE_SYNC_REMOTE`.
- Repointed referenced workspace hints to the staged
`project-<projectId>` sandbox directories and published
`PAPERCLIP_WORKSPACES_JSON`.
- Counted per-project remote staging failures as first-class `staging`
failures in the requested-vs-synced observability.
## Verification
- The pushed ref
`refs/heads/feat/sync-referenced-projects-remote-sandbox` resolves to
the authorized submit SHA.
- `git log --oneline
origin/master..origin/feat/sync-referenced-projects-remote-sandbox`
shows exactly the three expected commits.
- The handoff reports server typecheck clean, adapter-utils typecheck
clean, and the listed unit tests passing.
- The handoff also reports no open review comments and no Greptile score
yet.
## Risks
- The change touches authorization and sandbox path handling, so
regressions could block remote runs or expose the wrong project context.
- The new flag defaults on, so any bug in the remote path affects normal
remote use.
- SSH stays out of scope, so the two transport paths must remain
distinct.
## Model Used
OpenAI GPT-5 via Codex. Tool use enabled. Context window not reported in
this run.
## Checklist
- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` /
`Closes: #` / `Refs: #` OR (b) described the issue in-PR following the
relevant issue template
- [x] I have not referenced internal/instance-local Paperclip issues or
links (only public GitHub `#NNN` / `github.com/paperclipai/paperclip`
URLs)
- [x] My branch name describes the change (e.g. `docs/...`, `fix/...`)
and contains no internal Paperclip ticket id or instance-derived details
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] All Paperclip CI gates are green
- [x] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge
---------
Co-authored-by: Paperclip <noreply@paperclip.ing>
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