## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work
> - Sandbox-backed runs need observable startup behavior so operators
can see where time is spent before an adapter is invoked
> - The current startup path only surfaced aggregate timing, which makes
it hard to identify the slow boundary in the bring-up sequence
> - That gap matters because sandbox startup latency is often dominated
by one specific step, and aggregate timing hides the bottleneck
> - This pull request adds per-step startup timing events for the named
sandbox bring-up boundaries
> - The benefit is more precise observability with no control-flow
change and no schema migration
## Linked Issues or Issue Description
### Subsystem affected
Cross-cutting (multiple of the above)
### Problem or motivation
Sandbox run startup only exposed aggregate timing. That makes it hard to
identify which bring-up boundary is responsible for slow starts,
especially in remote or sandboxed execution where the bottleneck can
move between workspace setup, skill reconciliation, bridge setup, and
adapter handshake.
### Proposed solution
Emit a structured timing event for each named startup boundary before
the adapter is invoked, so the existing run-event stream carries
per-step duration data. This keeps the event path additive and lets
operators see which step dominates startup latency without changing
control flow or introducing a schema migration.
### Alternatives considered
- Keep only the aggregate startup duration: simpler, but it hides the
bottleneck and makes regression analysis much harder.
- Add a new telemetry sink or schema field: rejected because the
existing run-event payload already carries structured event data and
does not need a new storage path.
- Log unstructured text for each step: rejected because it is harder to
query and aggregate than a structured `step` + `durationMs` event.
### Roadmap alignment
This fits the roadmap direction around cloud / sandbox agents and
enforced outcomes by improving observability for sandboxed execution
without changing the control plane model. The roadmap section is broad,
but it does not call out this specific startup-timing work as a planned
duplicate.
### Additional context
This PR is intentionally additive. It records timing for the named
startup boundaries in the existing event stream and leaves the bridge,
database shape, and adapter invocation order unchanged.
## What Changed
- Added a `measureStartupStep` helper that times a startup step, emits
one structured `run.startup.step` event, and rethrows failures after
recording duration
- Wrapped the seven sandbox bring-up boundaries in `execute.ts` so the
structured timing covers each named step before adapter invocation
- Added unit coverage for the helper and integration coverage for the
startup-step events in the adapter-utils execute path
- Kept the event path additive, with no bridge change and no database
migration
## Verification
- `tsc --noEmit` for `@paperclip/adapter-utils`
- `pnpm test` in `packages/adapter-utils` equivalent suite coverage: 292
passed, 4 skipped
- Adjacent server event/log-store suites: `run-log-store.test.ts` and
`heartbeat-run-log.test.ts` passed (11 total)
- Git validation: fetched `origin/feat/sandbox-startup-step-timing`,
confirmed it matches the authorized submit SHA, and confirmed
`origin/master..origin/feat/sandbox-startup-step-timing` contains the
expected single commit
- Searched GitHub for duplicate or related open PRs/issues and found no
overlapping open items
- Checked `ROADMAP.md`; the roadmap covers sandboxed environments
generally, but does not call out this specific startup-timing
observability work as a planned duplicate
## Risks
- Low risk: the change is additive and only emits additional structured
events
- If downstream consumers assume startup events are aggregate-only, they
may need to ignore or account for the new `run.startup.step` entries
- Timing is measured via the injected clock and event emission happens
in a `finally`, so failures still report duration before rethrowing
## Model Used
OpenAI 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
- [ ] 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: Harold Kim <harold@paperclip.ing>
Co-authored-by: Paperclip <noreply@paperclip.ing>
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