Devin Foley
8f4b491d9a
## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work
> - Creating an agent starts at **New Agent → "manually" → pick an
adapter**, which routes to
`/{company}/agents/new?adapterType=claude_local` and renders the
`NewAgent` page with the `AgentConfigForm`
> - `AgentConfigForm` hands the parent a `triggerTestEnvironment`
callback via an `onTestActionChange` effect so the page can wire up its
"Test"/"Save + Test" button
> - That trigger was rebuilt on every render: it depended on
`runEnvironmentTest`, which is derived from a react-query `useMutation`
result, and `useMutation` returns a **brand-new result object identity
on every render**
> - So the `onTestActionChange` effect re-fired every render and pushed
a new function into the parent's state, producing an infinite `setState`
loop ("Maximum update depth exceeded") that threw during render
> - The app's custom router updates location **without remounting**, and
there was no error boundary around the routed outlet, so the throw left
a dead render tree — a fully **blank page** that stayed blank on
back-navigation until a hard refresh
> - This pull request stabilizes the trigger with a latest-ref pattern
so the effect no longer re-fires, and adds a route-keyed error boundary
so any future render throw degrades to a recoverable error card instead
of a blank screen
> - The benefit is that creating an agent works again, and render-time
failures anywhere in the routed UI are contained and recoverable rather
than silently blanking the app
## Linked Issues or Issue Description
No public GitHub issue exists, so the underlying bug is described inline
following the bug report template
(`.github/ISSUE_TEMPLATE/bug_report.yml`):
### What happened?
In the UI, choosing **New Agent → "manually" → (any adapter, e.g.
Claude)** navigates to the agent-config page and renders a **completely
blank page**. The browser console shows React's `Maximum update depth
exceeded`. Using the back button changes the URL but the page stays
blank until a full hard refresh.
### Expected behavior
Selecting an adapter shows the agent configuration form so the agent can
be created.
### Steps to reproduce
1. Open the app and click **New Agent**.
2. Choose **manually**.
3. Pick an adapter (e.g. Claude / `claude_local`).
4. Observe the blank page (URL becomes
`/{company}/agents/new?adapterType=claude_local`).
### Paperclip version or commit
Reproduces on `master` (base of this PR).
### Deployment mode
Reproduces regardless of deployment mode — it is a client-side render
loop.
### Root cause
`useMutation` returns a new result object identity each render, so the
`runEnvironmentTest`-derived `triggerTestEnvironment` callback was
unstable, which made the `onTestActionChange` effect push a new function
into parent state every render → infinite update loop → render throw →
no boundary → blank tree.
## What Changed
- **`ui/src/components/AgentConfigForm.tsx`** — Stabilize the
environment-test trigger handed to the parent using a latest-ref
pattern: the churny behavior (`runEnvironmentTest`,
`testEnvironmentDisabled`) lives in a `useRef` updated by an effect, and
the exposed `triggerTestEnvironment` is a `useCallback(() =>
triggerRef.current(), [])` with an empty dep array, so its identity is
stable across renders and the `onTestActionChange` effect no longer
re-fires every render.
- **`ui/src/components/RouteErrorBoundary.tsx`** (new) — A route-keyed
React error boundary that catches render throws and renders a
recoverable error card (showing the error message, with "Go back" and
"Reload page" actions). It resets automatically when the route
(`pathname + search`) changes.
- **`ui/src/components/Layout.tsx`** — Wrap the routed `<Outlet />` in
`<RouteErrorBoundary>` so a render throw degrades to the error card
instead of a blank page.
- **`ui/src/components/RouteErrorBoundary.test.tsx`** (new) — Regression
test: a throwing child is contained as a recoverable error card (showing
the message), "Go back" calls `navigate(-1)`, and the boundary resets to
render children again after the route changes.
## Verification
- `npx vitest run ui/src/components/RouteErrorBoundary.test.tsx` → 3
passed (regression test for this fix).
- `npx vitest run ui/src/components/AgentConfigForm.test.ts` → 9 passed.
- `npx tsc -b` in `ui` → 0 errors.
- Manual: ran the dev server, clicked **New Agent → manually → Claude**.
- **Before:** blank page; console logs `Maximum update depth exceeded`;
back button leaves the page blank until hard refresh.
- **After:** the agent configuration form renders normally and the agent
can be created; navigating away and back works without a hard refresh.
- Boundary check: with the loop still in place (pre-fix), the new
boundary catches the throw and shows a recoverable error card instead of
a blank screen; "Go back" / route change resets it.
_Screenshots: the before-state is the React `Maximum update depth
exceeded` error and a blank `/agents/new` page; the after-state is the
rendered agent-config form. Both were observed locally; rendered images
can be attached on request._
## Risks
- **Low risk.** Changes are confined to three UI files with no API,
schema, or behavioral change to agent creation beyond fixing the loop.
- The latest-ref pattern preserves identical runtime behavior of the
test trigger (same guard, same `runEnvironmentTest()` call) — it only
stabilizes the callback identity.
- The error boundary is additive; on the happy path it renders its
children unchanged. Its only behavior is to catch render throws that
previously blanked the app.
## Model Used
Claude (Anthropic), model `claude-opus-4-8` — extended-thinking-capable,
tool-use (file edit, shell, tests). Used to diagnose the infinite render
loop, implement the latest-ref fix and route error boundary, and verify
via local typecheck/tests.
## 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] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [ ] If this change affects the UI, I have included before/after
screenshots (described textually in Verification — see note)
- [ ] I have updated relevant documentation to reflect my changes (N/A —
bug fix, no docs affected)
- [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
@paperclipai/ui
Published static assets for the Paperclip board UI.
What gets published
The npm package contains the production build under dist/. It does not ship the UI source tree or workspace-only dependencies.
Storybook
Storybook config, stories, and fixtures live under ui/storybook/.
pnpm --filter @paperclipai/ui storybook
pnpm --filter @paperclipai/ui build-storybook
Typical use
Install the package, then serve or copy the built files from node_modules/@paperclipai/ui/dist.