## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work
> - The sandbox runtime depends on efficiently staging files into remote
environments
> - The process-session bridge was rewriting a static remote script on
every start, even when the remote copy already matched
> - That caused unnecessary round trips and made the startup path
noisier than it needed to be
> - This pull request adds a hash-skip path for the process-session
script write and keeps the existing bridge-entrypoint hash gate on the
same helper
> - It also locks in the reduced inbound round-trip count so the
collapse from the prior PR cannot silently regress
> - The benefit is fewer remote execs on warm starts and a stronger
guard against performance regressions
## Linked Issues or Issue Description
- Refs: https://github.com/paperclipai/paperclip/pull/10354
### Feature request-style description
**Subsystem affected**
- Cross-cutting (packages/adapter-utils and sandbox staging helpers)
**Problem or motivation**
- The process-session bootstrap path was rewriting a static remote
script on every start even when the remote file already matched the host
content.
- That added avoidable remote execs and latency to warm starts.
- The inbound staging collapse from the previous PR also needed a
regression lock so it could not silently drift back to extra round
trips.
**Proposed solution**
- Route the process-session remote script upload through the existing
hash-skip helper used by the sandbox callback bridge entrypoint.
- Keep the bridge-entrypoint behavior unchanged by delegating it to the
same helper.
- Add a regression test that asserts the inbound staging path still
collapses to the expected round-trip count.
**Alternatives considered**
- Keep the existing unconditional write path and accept the extra execs
on warm starts. Rejected because it preserves avoidable overhead.
- Add a second specialized helper just for process-session scripts.
Rejected because the bridge-entrypoint logic already solved the same
problem and should stay aligned.
**Roadmap alignment**
- This fits the roadmap items around cloud/sandbox agents and enforced
outcomes by reducing bootstrap waste and preventing performance
regressions.
- It does not introduce new product surface area, telemetry, or
user-facing workflow changes.
**Additional context**
- The implementation preserves the existing upload/verify/rename
behavior when the remote content differs and only skips the write when
the hash already matches.
- PR #10354 collapsed the inbound staging path; this PR preserves that
win.
## What Changed
- Added a shared hash-skip helper for remote text-file synchronization
so unchanged content skips the write path after a single remote hash
check.
- Switched the process-session remote script upload to use that helper,
preserving the existing write/verify/rename behavior when the remote
content differs.
- Refactored the sandbox callback bridge entrypoint sync to use the same
helper without changing its observable behavior.
- Added a mocked-native-runner regression test that locks the inbound
staging path to one `client.syncIn` round-trip per step and zero direct
write/run execs.
## Verification
- `tsc --noEmit`
- `pnpm --filter @paperclipai/adapter-utils exec vitest run`
- Full adapter-utils vitest sweep: 338 passed / 4 skipped
## Risks
- Low risk: the helper changes when a write occurs, not the script
contents or the remote execution surface.
- A hash-check failure now fails loudly instead of silently rewriting,
which is safer but could surface provider-side issues earlier than
before.
- The regression test is intentionally specific to the current collapsed
staging path, so future architectural changes will need test updates.
## Model Used
OpenAI Codex (GPT-5, tool-using coding agent)
## 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: Harold Kim <harold@paperclip.ing>
Co-authored-by: Paperclip <noreply@paperclip.ing>
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