## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work.
> - The server and the browser need clear error reports when an operator
enables external monitoring.
> - Paperclip already uses an opt-in OpenTelemetry pattern for server
traces.
> - Sentry can provide error reports for both runtime paths when the
operator sets one data source name.
> - This pull request adds one opt-in Sentry gate for the server and the
browser.
> - The benefit is faster diagnosis while the default setup sends no
Sentry data.
## Linked Issues or Issue Description
**What is improved?**
Paperclip gains optional error monitoring for server and browser
failures.
**Subsystem affected**
Cross-cutting (server, UI, and shared authentication data).
**Current behavior**
Paperclip has no built-in Sentry error capture for server failures or
browser boundary failures. Operators must inspect local logs and browser
tools.
**Proposed behavior**
When the operator sets `SENTRY_DSN`, the server and authenticated
browser use the same Sentry project. When the variable is absent, both
paths stay inactive. The server loads Sentry dynamically and fails open
when the optional package is absent.
**Reason and benefit**
Operators can inspect runtime errors in one Sentry project. The default
setup remains local and sends no monitoring data.
**Breaking changes**
None when `SENTRY_DSN` remains unset. Authenticated session responses
add the optional `sentryDsn` field.
**Additional context**
The implementation uses built-in Sentry privacy options. It disables
default HTTP context and breadcrumb integrations and keeps
`sendDefaultPii` false.
## What Changed
- Add an opt-in server Sentry gate with dynamic package loading and
fail-open behavior.
- Add the Sentry data source name to the authenticated session response.
- Add an authenticated browser Sentry gate and React error boundary
capture.
- Add tests for server, browser, route, and application error paths.
- Document activation, installation, privacy settings, capture behavior,
and operator controls.
## Verification
- Run `npx vitest run server/src/__tests__/sentry.test.ts`.
- Run `npx vitest run ui/src/lib/sentry.test.ts`.
- Run `npx vitest run server/src/__tests__/auth-routes.test.ts
server/src/__tests__/shutdown.test.ts`.
- Confirm that the full continuous integration suite passes on this pull
request.
- Leave `SENTRY_DSN` unset and confirm that the server and browser gates
stay inactive.
- Set `SENTRY_DSN` and install the optional Sentry packages before a
manual capture check.
## Risks
The operator controls the Sentry project and accepts the data risk when
the operator enables the feature. Error objects can contain messages,
stacks, or cause chains with private values. The default configuration
sends no data because the feature stays off without `SENTRY_DSN`. A
missing optional server package does not stop server boot.
## Model Used
OpenAI Codex, GPT-5, with tool use, repository inspection, GitHub CLI
operations, and code review support.
## 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>
## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work
> - The web UI holds live websocket connections for run events,
coordinates cross-tab polling through a leader-election store, and
renders app chrome (sidebar, providers) around a routed outlet
> - When the backend is still cold-starting (managed hosting wake,
server restart, reverse proxy up before the app), the event websockets
refuse connections and the first SPA load mounts against a dead backend
> - In that state the mount cascade can exceed React's nested update
limit (minified error #185); the crash originates in shell hooks outside
the routed error boundary, so React unmounts the entire root to a blank
page, and the dead page keeps retrying the websocket on a flat 1.5s
timer until the user hard-refreshes
> - This pull request removes the wasted nested commits from the
shared-polling subscription path, adds exponential backoff to the
transcript websocket reconnect, and adds a last-resort app-shell error
boundary
> - The benefit is that a cold or briefly unreachable backend degrades
to a recoverable state instead of a blank page that hammers the server
## Linked Issues or Issue Description
No existing issue. Description follows the bug template:
**What happened?**
On the first load against a backend that was still starting, the app
showed its loading animation and then a blank page. The console showed
repeated `WebSocket connection to 'wss://…/api/companies/<id>/events/ws'
failed` lines and `Uncaught Error: Minified React error #185` with a
stack through the shared-polling coordinator's `subscribe`. The
websocket retries continued indefinitely on the dead page. A manual
refresh fixed it.
**Expected behavior**
A backend that is briefly unreachable degrades gracefully: websocket
reconnects back off, the UI keeps rendering from cache, and even a
worst-case crash shows a reload prompt instead of a blank page.
**Steps to reproduce**
1. Serve the UI while the backend API is still starting (websocket
upgrades and API calls refused).
2. Load any company page with several shared-polling consumers mounted
(dashboard with sidebar).
3. Observe repeated websocket failures; on affected loads the page goes
blank with React error #185.
## What Changed
- `ui/src/hooks/useSharedPolling.ts`: coordinator snapshot notifications
now keep the previous state object when leadership did not change, so
React bails out instead of scheduling a nested re-render. `subscribe`
invokes its listener synchronously from inside the mount effect with a
fresh object each time; before this change every mount and notify burned
nested-update budget even with no value change — the crash frame in the
field report was exactly this `subscribe → setState` call.
- `ui/src/components/transcript/useLiveRunTranscripts.ts`: the live
event websocket reconnect backs off exponentially (1.5s → 15s cap, reset
on successful open), mirroring `LiveUpdatesProvider`, instead of a flat
1.5s retry.
- `ui/src/components/AppErrorBoundary.tsx` (+ wiring in
`ui/src/main.tsx`): a dependency-free boundary above the router and
providers. `RouteErrorBoundary` only guards the routed `<Outlet />`; a
crash in the shell around it had no boundary, so React unmounted the
root to a blank page. The boundary renders a reload prompt with the
error message.
- Tests: `useSharedPollingSnapshot.test.tsx` (mount costs no extra
commit — fails against the previous code; a real leadership change
re-renders exactly once and ticks stay quiet), a backoff test in
`useLiveRunTranscripts.test.tsx` (delays grow 1.5s → 3s → 6s and reset
after a successful open), and `AppErrorBoundary.test.tsx` (render throw,
effect throw, healthy pass-through).
## Verification
- `pnpm vitest run` in `ui/` over the touched suites (shared polling,
cross-tab poll, transcripts, boundary): 34 tests pass.
- `pnpm typecheck` in `ui/` — clean.
- The snapshot regression test was verified to fail against the
pre-change hook (extra commit per mount).
- Not reproduced end-to-end: the exact 50-update cascade from the field
crash needs a live cold backend; the change removes the identified
per-mount/per-notify nested commits at the reported crash frame, bounds
the reconnect load, and guarantees the shell can no longer blank the
page.
## Risks
Low risk. The snapshot change only suppresses re-renders whose state is
value-identical; leadership changes propagate exactly as before. The
backoff only lengthens retry delays after consecutive failures and
resets on success. The new boundary renders children untouched unless an
error reaches it; behavior on healthy loads is unchanged. Self-hosted
deployments see the same code paths — the cold-backend window simply
rarely occurs there.
## Model Used
- Claude (Anthropic), Claude Fable 5 (`claude-fable-5`), via Claude Code
CLI with extended thinking and tool use (code search, edit, test
execution; diagnosis included mapping the production minified stack to
source).
## 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
- [x] I will address all Greptile and reviewer comments before
requesting merge
Nicky Leach
Devin Foley