## Thinking Path
> - Paperclip manages AI agents and their work.
> - The runner executes agent turns on local and remote providers.
> - A remote per-turn session must save its state before Paperclip
releases its sandbox.
> - The session runtime returned after 100 milliseconds while the remote
checkpoint still ran.
> - The next turn also checked the local state path instead of the
verified remote backup.
> - This pull request waits for the bounded remote close and accepts
only a verified suspended backup.
> - The benefit is reliable multi-turn execution without weaker identity
checks.
## Linked Issues or Issue Description
**What happened?**
A successful remote agent turn released its sandbox before the runner
saved the verified continuation backup. The next turn failed with
`runner_state_identity_mismatch`.
**Expected behavior**
Paperclip must finish the bounded remote checkpoint before it releases
the sandbox. A later turn must validate and restore the digest-matched
suspended backup.
**Steps to reproduce**
1. Run a native ACPX Claude Plan test in a non-reusable Daytona sandbox.
2. Reject the first plan to start a second turn.
3. Observe that the second turn fails before provider execution.
**Paperclip version or commit**
The failure reproduced at `13775a90b078ff64872f50961ea1b83d575e7bc6`.
**Deployment mode**
GitHub Actions with a Daytona sandbox.
## What Changed
- Wait for the internally bounded remote runner close and checkpoint
before the host returns.
- Preserve the existing short cleanup bound for other providers.
- Validate remote continuation lifecycle from a complete digest-verified
backup when local runner state is absent.
- Keep corrupt, non-suspended, mismatched, and unverified state
fail-closed.
- Make native Plan completion and accepted-Plan wake prompts
deterministic.
## Verification
- A prior 45-cell local campaign passed 44 cells. The only failure was
the OpenCode Plan prompt variance fixed here.
- A focused OpenCode local Plan rerun passed.
- ACPX Claude Daytona message and question cells passed.
- Focused regressions cover delayed checkpoint close and verified remote
backup lifecycle.
- GitHub Build and the focused ACPX Claude Daytona Plan cell will
validate this exact head.
## Risks
Remote runnerd sessions now wait for their internally bounded
close/checkpoint path before returning; generic provider cleanup retains
the existing 100 millisecond bound. Durable run success still cannot be
reversed. The environment release guard still blocks sandbox destruction
when no verified backup stamp exists.
## Model Used
OpenAI Codex, GPT-5.6, extended reasoning, with code execution and
GitHub Actions inspection.
## 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 and contains no internal task
id
- [ ] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [ ] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [ ] All Paperclip CI gates are green
- [ ] Greptile is 5/5 with no open findings
- [ ] I will address all Greptile and reviewer comments before
requesting merge
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