## Thinking Path
> - Paperclip uses spans and traces to show how work moves through
agents and tools
> - sandbox.exec spans need a real parent so the trace tree matches the
work tree
> - Wrong parent links make execution history hard to read and hard to
debug
> - This pull request adds a single task.run root span and re-parents
live work to the nearest active span
> - The change keeps detached work under the closest live span instead
of the HTTP root
> - The benefit is a clear trace tree for sandbox.exec work and better
execution diagnosis
## Linked Issues or Issue Description
**What happened?**
sandbox.exec spans attached to the wrong parent or to no live parent in
some paths.
**Expected behavior**
Each sandbox.exec span should attach to the nearest live span.
**Steps to reproduce**
1. Run work that creates sandbox.exec spans during startup and callback
bridge paths.
2. Inspect the trace tree.
3. Observe an orphaned span or a span with the wrong parent.
**Paperclip version or commit**
`672e9de9c8b004aebc1f08e24b612ab067735ad1`
**Deployment mode**
Local dev.
**Additional context**
The branch adds the task.run root span, parents sandbox.startup to it,
and re-parents detached bridge work to the nearest live span.
## What Changed
- Added a task.run root span for the run tree.
- Re-parented sandbox.startup, agent.turn, and detached bridge work to
the nearest live span.
- Added end-to-end trace-tree assertions for the full parent chain.
- Added negative coverage so sandbox.exec does not parent to the HTTP
root.
## Verification
- Focused Vitest suite passed:
`packages/adapter-utils/src/acpx-engine/execute.test.ts`,
`packages/adapter-utils/src/acpx-engine/startup-timing.test.ts`,
`packages/adapter-utils/src/execution-target-sandbox.test.ts`,
`packages/adapter-utils/src/sandbox-callback-bridge.test.ts`, and
`server/src/__tests__/environment-execution-target.test.ts`.
- Result: 5 files passed, 204 tests passed.
- The submitted branch also reported `adapter-utils` checks, `server`
seam checks, and `tsc` exit 0 in the handoff state.
## Risks
- This change can alter trace tree shape in tools that read parent
spans.
- A missed bridge path could still point to the wrong live span.
- Low risk for runtime behavior, because the change only changes span
parent attribution.
## Model Used
OpenAI GPT-5, tool-use capable.
## 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
- [ ] All Paperclip CI gates are green
- [ ] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [ ] I will address all Greptile and reviewer comments before
requesting merge
---------
Co-authored-by: Paperclip <noreply@paperclip.ing>
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