## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work.
> - Environment sandboxes already support custom image creation and
refresh through a temporary SSH setup session.
> - The existing workflow makes operators copy an SSH command into an
external terminal before they can install packages or make image
changes.
> - That extra context switch is slower, easier to get wrong, and less
integrated with the setup session Paperclip already tracks.
> - This pull request adds an embedded browser SSH terminal for custom
image setup, so operators can start working in the target sandbox
directly from the environment configuration flow.
> - The implementation uses short-lived websocket attachment tokens,
session-lifetime SSH host-key pinning, and server-managed terminal
cleanup so the feature fits the existing setup-session boundary.
> - The benefit is a smoother custom image creation and refresh
experience without asking users to leave Paperclip for routine sandbox
setup work.
## Linked Issues or Issue Description
No public GitHub issue exists.
### Subsystem affected
Cross-cutting: `server/` custom image setup APIs and websocket handling,
`ui/` environment configuration UI, and shared custom image contracts.
### Problem or motivation
Custom image creation and refresh require an operator to open a separate
SSH client, paste the command shown by Paperclip, perform setup work,
then return to the browser to finish the image flow. This is functional
but awkward for a setup process that already starts and tracks a
temporary sandbox session.
### Proposed solution
Embed an SSH terminal in the custom image setup UI. When a setup session
exposes an SSH payload, Paperclip should open a browser terminal backed
by a server-side websocket session, let the operator run setup commands
in-place, and then close the terminal when setup is finished, cancelled,
expired, or disconnected.
### Alternatives considered
- Keep the existing copy/paste SSH command workflow. This remains a
fallback, but it does not streamline the common path.
- Put SSH credentials directly into websocket URLs. This was avoided so
terminal authentication can happen in an explicit first websocket auth
frame rather than in logged URLs.
- Trust the SSH host blindly for every reconnect. This PR instead pins
the observed host-key fingerprint for the setup-session lifetime.
### Roadmap alignment
This fits the roadmap theme of making agent workspaces usable in more
remote and sandboxed environments while preserving Paperclip's
control-plane model.
### Additional context
Public GitHub search did not find a duplicate issue or PR for `custom
image terminal ssh` in `paperclipai/paperclip`.
## What Changed
- Added server-side terminal session tracking for custom image setup
sessions, including connect-token issuance, websocket attachment,
expiry, resize, input, and shutdown handling.
- Added an embedded browser terminal to the custom image creation and
refresh flow when a setup session provides SSH connection details.
- Moved terminal token authentication out of the websocket URL and into
the first websocket JSON auth frame.
- Added SSH host-key SHA-256 pinning for each terminal session and
documented the provider convention for username-embedded SSH
credentials.
- Updated the custom image environment API and UI so the setup terminal
can open, reconnect, show status, authenticate, resize, and remain
active for the setup-session lifetime once attached.
- Kept custom image setup routes company-scoped and closed active
terminal sessions on setup finish/cancel.
- Added focused unit/integration/UI coverage for token expiry,
setup-session expiry, websocket close paths, host-key pinning, and
terminal session lifecycle behavior.
- Removed the generated lockfile delta from the PR; CI owns temporary
lockfile regeneration for manifest-changing PRs.
## Verification
- `pnpm exec vitest run
server/src/__tests__/server-startup-feedback-export.test.ts
server/src/__tests__/environment-custom-image-terminal-ws.test.ts
server/src/services/environment-custom-image-terminal-sessions.test.ts
server/src/__tests__/environment-custom-image-routes.test.ts
packages/shared/src/environment-custom-images.test.ts
ui/src/pages/CompanyEnvironments.test.tsx`
- 6 test files passed
- 58 tests passed
- `pnpm --filter @paperclipai/server typecheck`
- `pnpm --filter @paperclipai/ui typecheck`
- `pnpm --filter @paperclipai/server build`
- `pnpm --filter @paperclipai/ui build`
- `pnpm run typecheck:build-gaps`
- `git diff --check`
- Local sensitive-content scan over the PR diff using patterns for API
keys, private keys, private hostnames, local paths, token fields, and
credential-like strings.
- Findings were limited to removed URL-token code and synthetic test
placeholders such as `ssh-token-secret` and
`terminal-token-terminal-token-123456`.
- No real credentials, private hostnames, local filesystem paths, or
instance-local links were found.
- Remote PR checks were green after the implementation commit, including
Build, Typecheck + Release Registry, General tests, serialized server
suites, e2e, verify, Socket, Snyk, Superagent, and Greptile 5/5.
- Post-merge PR hardening on July 3, 2026: merged `origin/master` at
`47448721e` into the branch, resolved the `CompanyEnvironments.tsx`
import conflict, reran focused tests, server/UI typechecks, server/UI
builds, `pnpm run typecheck:build-gaps`, and `git diff --check`, scanned
the final diff for sensitive content, pushed `4b43558cc`, and confirmed
all remote checks plus Greptile 5/5 were green.
- PR metadata correction on July 3, 2026: changed the title/body framing
from bug-fix language to feature-request language. No source files
changed for this metadata-only update.
## Risks
- Moderate surface area because this adds websocket routing,
setup-session runtime state, package dependencies, and a new custom
image UI path.
- New websocket attachments still require valid short-lived tokens;
established terminal sessions remain bounded by setup-session expiry,
explicit finish/cancel, client close, or server shutdown.
- The terminal-session store is in-memory, so active terminal websocket
tokens and host-key pins do not survive server restarts.
- SSH host-key verification uses session-lifetime TOFU pinning because
the current provider payload does not expose a trusted host-key
fingerprint.
- The external SSH command remains important as a fallback if a browser,
proxy, or network environment cannot sustain the websocket terminal.
> For core feature work, check [`ROADMAP.md`](ROADMAP.md) first and
discuss it in `#dev` before opening the PR. Feature PRs that overlap
with planned core work may need to be redirected — check the roadmap
first. See `CONTRIBUTING.md`.
## Model Used
OpenAI Codex, GPT-5 coding agent with shell/tool execution. Context
window size was not exposed in this runtime.
## 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>
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